---------------------------------------------------------- RVSouthEast-List Digest Archive --- Total Messages Posted Sun 01/28/07: 13 ---------------------------------------------------------- Today's Message Index: ---------------------- 1. 04:20 AM - Re: Fuel Pressure Fixed (Ron Schreck) 2. 04:29 AM - Re: Fuel Pressure Fixed (Steve Glasgow) 3. 05:06 AM - Re: Fuel Pressure Fixed (Bill Boyd) 4. 05:28 AM - Re: Fuel Pressure Fixed (Steve Glasgow) 5. 05:44 AM - Re: Fuel Pressure Fixed (Bill Boyd) 6. 05:58 AM - Re: Fuel Pressure Fixed (James Clark) 7. 06:31 AM - Re: Fuel Pressure Fixed (Bill Boyd) 8. 07:25 AM - bubbles and pressure was : Fuel Pressure Fixed (Ed Anderson) 9. 10:24 AM - Re: bubbles and pressure was : Fuel Pressure Fixed (Bill Boyd) 10. 10:57 AM - Re: bubbles and pressure was : Fuel Pressure Fixed (Steve Glasgow) 11. 06:22 PM - Re: bubbles and pressure was : Fuel Pressure Fixed (Bill Boyd) 12. 06:28 PM - Re: bubbles and pressure was : Fuel Pressure Fixed (Bill Boyd) 13. 07:48 PM - Re: bubbles and pressure was : Fuel Pressure Fixed (Ed Anderson) ________________________________ Message 1 _____________________________________ Time: 04:20:37 AM PST US From: "Ron Schreck" Subject: RE: RVSouthEast-List: Fuel Pressure Fixed Steve, Glad to hear you are back in the air. Actually, your problem and solution makes perfect sense to me (Monday morning quarterbacking, however). If your fuel and oil pressure sensors are mounted high on the firewall, it only makes sense that any air trapped in the lines will never bleed out (down hill) without some help. True, the trapped air may transfer some measure of pressure, but being much more compressible than a liquid it would certainly be a false reading. I think your solution merits a mention on the RV list and perhaps a suggestion that these sensors be mounted low on the firewall to avoid the problem altogether. Nice work, Cappy! Smokey -----Original Message----- From: owner-rvsoutheast-list-server@matronics.com [mailto:owner-rvsoutheast-list-server@matronics.com] On Behalf Of Steve Glasgow Sent: Saturday, January 27, 2007 5:13 PM Subject: RVSouthEast-List: Fuel Pressure Fixed --> Turns out there was apparently air in the line to the sender. Probably from lines being open on annual. I flew before doing the procedure below and the fuel pressure was all over the place. From 4 to 9.5 psi. Anyway here is what to do to get the air out. Disconnect wires from fuel sender. Loosen sender so it can be moved by hand. Keep sender hand tight and turn on electric pump. Now loosen sender till fuel comes out around the pipe fitting. Then tighten to stop the fuel from leaking. Turn off electric pump, secure sender and hook up wires. Done. From now on I will do this procedure whenever a fuel line is opened. I flew before doing this and the fuel pressure was all over the place. >From 4 to 9.5 psi. Cappy -- 1/26/2007 11:11 AM -- 1/27/2007 5:02 PM ________________________________ Message 2 _____________________________________ Time: 04:29:09 AM PST US From: "Steve Glasgow" Subject: Re: RVSouthEast-List: Fuel Pressure Fixed Thanks for the Kudos Smokey! As you know I have been dealing with Low or High fuel pressure since the beginning so I'm whiting till the jury is in. I have ordered a direct reading pressure gauge that should be here Wednesday. Then I can find out what the "real fuel pressure" is. Cappy ----- Original Message ----- From: Ron Schreck To: rvsoutheast-list@matronics.com Sent: Sunday, January 28, 2007 7:17 AM Subject: RE: RVSouthEast-List: Fuel Pressure Fixed Steve, Glad to hear you are back in the air. Actually, your problem and solution makes perfect sense to me (Monday morning quarterbacking, however). If your fuel and oil pressure sensors are mounted high on the firewall, it only makes sense that any air trapped in the lines will never bleed out (down hill) without some help. True, the trapped air may transfer some measure of pressure, but being much more compressible than a liquid it would certainly be a false reading. I think your solution merits a mention on the RV list and perhaps a suggestion that these sensors be mounted low on the firewall to avoid the problem altogether. Nice work, Cappy! Smokey -----Original Message----- From: owner-rvsoutheast-list-server@matronics.com [mailto:owner-rvsoutheast-list-server@matronics.com] On Behalf Of Steve Glasgow Sent: Saturday, January 27, 2007 5:13 PM To: SERV Subject: RVSouthEast-List: Fuel Pressure Fixed --> Turns out there was apparently air in the line to the sender. Probably from lines being open on annual. I flew before doing the procedure below and the fuel pressure was all over the place. From 4 to 9.5 psi. Anyway here is what to do to get the air out. Disconnect wires from fuel sender. Loosen sender so it can be moved by hand. Keep sender hand tight and turn on electric pump. Now loosen sender till fuel comes out around the pipe fitting. Then tighten to stop the fuel from leaking. Turn off electric pump, secure sender and hook up wires. Done. From now on I will do this procedure whenever a fuel line is opened. I flew before doing this and the fuel pressure was all over the place. >From 4 to 9.5 psi. Cappy -- 1/26/2007 11:11 AM -- 1/27/2007 5:02 PM ________________________________ Message 3 _____________________________________ Time: 05:06:32 AM PST US From: "Bill Boyd" Subject: Re: RVSouthEast-List: Fuel Pressure Fixed Smokey, I think the trapped air compresses until it reaches equilib. and then transmits all the pressure on down the line... in doing so it will tend to dampen any pulses (soften the water-hammer effect, what-have-you) but I think all the pressure will show up at the transducer. Enlighten me if I'm overlooking the obvious. It sounds like Cappy might have fixed his gauge but broken some law of physics. Typical Cappy maneuver if you ask me. Today I shall have to see if he messed up Bernouli and Newton's, by seeing if my wing still generates enough lift to fly :-) Cappy, I'd appreciate it if you wouldn't break or damage physical laws that the rest of us use every day, just to get your gauges reading correctly; that's very selfish and won't be tolerated. -Stormy On 1/28/07, Ron Schreck wrote: > > Steve, > > Glad to hear you are back in the air. Actually, your problem and > solution makes perfect sense to me (Monday morning quarterbacking, > however). If your fuel and oil pressure sensors are mounted high on the > firewall, it only makes sense that any air trapped in the lines will > never bleed out (down hill) without some help. True, the trapped air > may transfer some measure of pressure, but being much more compressible > than a liquid it would certainly be a false reading. I think your > solution merits a mention on the RV list and perhaps a suggestion that > these sensors be mounted low on the firewall to avoid the problem > altogether. Nice work, Cappy! > > Smokey > > -----Original Message----- > From: owner-rvsoutheast-list-server@matronics.com > [mailto:owner-rvsoutheast-list-server@matronics.com] On Behalf Of Steve > Glasgow > Sent: Saturday, January 27, 2007 5:13 PM > To: SERV > Subject: RVSouthEast-List: Fuel Pressure Fixed > > > --> > > Turns out there was apparently air in the line to the sender. Probably > from > lines being open on annual. > > I flew before doing the procedure below and the fuel pressure was all > over > the place. From 4 to 9.5 psi. > > Anyway here is what to do to get the air out. Disconnect wires from > fuel > sender. Loosen sender so it can be moved by hand. Keep sender hand > tight > and turn on electric pump. Now loosen sender till fuel comes out around > the > pipe fitting. Then tighten to stop the fuel from leaking. Turn off > electric pump, secure sender and hook up wires. Done. From now on I > will > do this procedure whenever a fuel line is opened. > > I flew before doing this and the fuel pressure was all over the place. > >From > 4 to 9.5 psi. > > Cappy > > > -- > 1/26/2007 11:11 AM > > > -- > 1/27/2007 5:02 PM > > ________________________________ Message 4 _____________________________________ Time: 05:28:07 AM PST US From: "Steve Glasgow" Subject: Re: RVSouthEast-List: Fuel Pressure Fixed What about compressibility of a gas verses a liquid. Water pipes have air trapped in them all the time to prevent hammer effect. The pressure sender is up the line not down the line. Pressure is correct at the engine, just not the pressure sender which is way above the carburetor. You may be correct if the sender is plumbed at the carburetor but mine isn't. All I know is it worked. No more oscillating fuel pressure. Stormy, are you giving us bad coordinates again? Love Cappy ----- Original Message ----- From: Bill Boyd To: rvsoutheast-list@matronics.com Sent: Sunday, January 28, 2007 8:05 AM Subject: Re: RVSouthEast-List: Fuel Pressure Fixed Smokey, I think the trapped air compresses until it reaches equilib. and then transmits all the pressure on down the line... in doing so it will tend to dampen any pulses (soften the water-hammer effect, what-have-you) but I think all the pressure will show up at the transducer. Enlighten me if I'm overlooking the obvious. It sounds like Cappy might have fixed his gauge but broken some law of physics. Typical Cappy maneuver if you ask me. Today I shall have to see if he messed up Bernouli and Newton's, by seeing if my wing still generates enough lift to fly :-) Cappy, I'd appreciate it if you wouldn't break or damage physical laws that the rest of us use every day, just to get your gauges reading correctly; that's very selfish and won't be tolerated. -Stormy On 1/28/07, Ron Schreck wrote: > > Steve, > > Glad to hear you are back in the air. Actually, your problem and > solution makes perfect sense to me (Monday morning quarterbacking, > however). If your fuel and oil pressure sensors are mounted high on the > firewall, it only makes sense that any air trapped in the lines will > never bleed out (down hill) without some help. True, the trapped air > may transfer some measure of pressure, but being much more compressible > than a liquid it would certainly be a false reading. I think your > solution merits a mention on the RV list and perhaps a suggestion that > these sensors be mounted low on the firewall to avoid the problem > altogether. Nice work, Cappy! > > Smokey > > -----Original Message----- > From: owner-rvsoutheast-list-server@matronics.com > [mailto:owner-rvsoutheast-list-server@matronics.com] On Behalf Of Steve > Glasgow > Sent: Saturday, January 27, 2007 5:13 PM > To: SERV > Subject: RVSouthEast-List: Fuel Pressure Fixed > > > --> > > Turns out there was apparently air in the line to the sender. Probably > from > lines being open on annual. > > I flew before doing the procedure below and the fuel pressure was all > over > the place. From 4 to 9.5 psi. > > Anyway here is what to do to get the air out. Disconnect wires from > fuel > sender. Loosen sender so it can be moved by hand. Keep sender hand > tight > and turn on electric pump. Now loosen sender till fuel comes out around > the > pipe fitting. Then tighten to stop the fuel from leaking. Turn off > electric pump, secure sender and hook up wires. Done. From now on I > will > do this procedure whenever a fuel line is opened. > > I flew before doing this and the fuel pressure was all over the place. > >From > 4 to 9.5 psi. > > Cappy > > > > > > > -- > 1/26/2007 11:11 AM > > > -- > 1/27/2007 5:02 PM > > > > > > > ________________________________ Message 5 _____________________________________ Time: 05:44:27 AM PST US From: "Bill Boyd" Subject: Re: RVSouthEast-List: Fuel Pressure Fixed Yeah, I've been known to lose my position fix on the internet before... I'm wrestling with this and want to understand it. You raise one (calibration) point below: the pressure you read will be less than carb pressure by the height of the fluid column betwee the carb and the transducer. Not sure how many inches of gasoline column equal one p.s.i., but it varies with gasoline versus air because of the differing densities. Same reason a barometer made with mercury is only a few feet tall versus one with water at around 32 feet tall! The way I look at it, the pressure at my air tool is at the same value as at the compressor regulator (until I squeeze the trigger and air flow in the line causes a "voltage drop" - I'm talking about static pressure, such as we read in a fuel pressure line that dead-ends into a transducer). To me this demonstrates that air sends its pressure down the hose just like any other fluid, otherwise my pneumatic tools would not work. I still believe that when your fuel system pressurizes, everything in the system, even trapped air, comes up to the same pressure and should read as such on any transducer. If I'm mistaken, let me know; meanwhile my air tools still work just dandy on this exact principle. But as you say, I've been wrong before. I only belabor the point b/c I'm not convinced that this could have fixed the problem and you might need to keep investigating. -Stormy On 1/28/07, Steve Glasgow wrote: > > > What about compressibility of a gas verses a liquid. Water pipes have air > trapped in them all the time to prevent hammer effect. The pressure sender > is up the line not down the line. Pressure is correct at the engine, just > not the pressure sender which is way above the carburetor. You may be > correct if the sender is plumbed at the carburetor but mine isn't. All I > know is it worked. No more oscillating fuel pressure. > > Stormy, are you giving us bad coordinates again? > > Love Cappy > > ----- Original Message ----- > From: Bill Boyd > To: rvsoutheast-list@matronics.com > Sent: Sunday, January 28, 2007 8:05 AM > Subject: Re: RVSouthEast-List: Fuel Pressure Fixed > > > Smokey, > > I think the trapped air compresses until it reaches equilib. and then > transmits all the pressure on down the line... in doing so it will > tend to dampen any pulses (soften the water-hammer effect, > what-have-you) but I think all the pressure will show up at the > transducer. Enlighten me if I'm overlooking the obvious. > > It sounds like Cappy might have fixed his gauge but broken some law of > physics. Typical Cappy maneuver if you ask me. Today I shall have to > see if he messed up Bernouli and Newton's, by seeing if my wing still > generates enough lift to fly :-) > > Cappy, I'd appreciate it if you wouldn't break or damage physical laws > that the rest of us use every day, just to get your gauges reading > correctly; that's very selfish and won't be tolerated. > > -Stormy > > On 1/28/07, Ron Schreck wrote: > > > > > Steve, > > > > Glad to hear you are back in the air. Actually, your problem and > > solution makes perfect sense to me (Monday morning quarterbacking, > > however). If your fuel and oil pressure sensors are mounted high on the > > firewall, it only makes sense that any air trapped in the lines will > > never bleed out (down hill) without some help. True, the trapped air > > may transfer some measure of pressure, but being much more compressible > > than a liquid it would certainly be a false reading. I think your > > solution merits a mention on the RV list and perhaps a suggestion that > > these sensors be mounted low on the firewall to avoid the problem > > altogether. Nice work, Cappy! > > > > Smokey > > > > -----Original Message----- > > From: owner-rvsoutheast-list-server@matronics.com > > [mailto:owner-rvsoutheast-list-server@matronics.com] On > Behalf Of Steve > > Glasgow > > Sent: Saturday, January 27, 2007 5:13 PM > > To: SERV > > Subject: RVSouthEast-List: Fuel Pressure Fixed > > > > > > --> > > > > Turns out there was apparently air in the line to the sender. Probably > > from > > lines being open on annual. > > > > I flew before doing the procedure below and the fuel pressure was all > > over > > the place. From 4 to 9.5 psi. > > > > Anyway here is what to do to get the air out. Disconnect wires from > > fuel > > sender. Loosen sender so it can be moved by hand. Keep sender hand > > tight > > and turn on electric pump. Now loosen sender till fuel comes out around > > the > > pipe fitting. Then tighten to stop the fuel from leaking. Turn off > > electric pump, secure sender and hook up wires. Done. From now on I > > will > > do this procedure whenever a fuel line is opened. > > > > I flew before doing this and the fuel pressure was all over the place. > > >From > > 4 to 9.5 psi. > > > > Cappy > > > > > > > > > > > > > > -- > > 1/26/2007 11:11 AM > > > > > > -- > > 1/27/2007 5:02 p; Features Subscriptions > href="http://www.matronics.com/Navigator?RVSouthEast-List">http://www.mp; > available via > href="http://forums.matronics.com">http://forums.matronics.com > > ________________________________ Message 6 _____________________________________ Time: 05:58:08 AM PST US From: "James Clark" Subject: Re: RVSouthEast-List: Fuel Pressure Fixed Consider this: Removing the "air" may have been the mechanism that removed some other "trapped particle" that might have been affecting the transducer. James On 1/28/07, Bill Boyd wrote: > > > Yeah, I've been known to lose my position fix on the internet before... > > I'm wrestling with this and want to understand it. You raise one > (calibration) point below: the pressure you read will be less than > carb pressure by the height of the fluid column betwee the carb and > the transducer. Not sure how many inches of gasoline column equal one > p.s.i., but it varies with gasoline versus air because of the > differing densities. Same reason a barometer made with mercury is > only a few feet tall versus one with water at around 32 feet tall! > > The way I look at it, the pressure at my air tool is at the same value > as at the compressor regulator (until I squeeze the trigger and air > flow in the line causes a "voltage drop" - I'm talking about static > pressure, such as we read in a fuel pressure line that dead-ends into > a transducer). To me this demonstrates that air sends its pressure > down the hose just like any other fluid, otherwise my pneumatic tools > would not work. > > I still believe that when your fuel system pressurizes, everything in > the system, even trapped air, comes up to the same pressure and should > read as such on any transducer. If I'm mistaken, let me know; > meanwhile my air tools still work just dandy on this exact principle. > But as you say, I've been wrong before. > > I only belabor the point b/c I'm not convinced that this could have > fixed the problem and you might need to keep investigating. > > -Stormy > > On 1/28/07, Steve Glasgow wrote: > > > > > > What about compressibility of a gas verses a liquid. Water pipes have > air > > trapped in them all the time to prevent hammer effect. The pressure > sender > > is up the line not down the line. Pressure is correct at the engine, > just > > not the pressure sender which is way above the carburetor. You may be > > correct if the sender is plumbed at the carburetor but mine > isn't. All I > > know is it worked. No more oscillating fuel pressure. > > > > Stormy, are you giving us bad coordinates again? > > > > Love Cappy > > > > ----- Original Message ----- > > From: Bill Boyd > > To: rvsoutheast-list@matronics.com > > Sent: Sunday, January 28, 2007 8:05 AM > > Subject: Re: RVSouthEast-List: Fuel Pressure Fixed > > > > > > > > Smokey, > > > > I think the trapped air compresses until it reaches equilib. and then > > transmits all the pressure on down the line... in doing so it will > > tend to dampen any pulses (soften the water-hammer effect, > > what-have-you) but I think all the pressure will show up at the > > transducer. Enlighten me if I'm overlooking the obvious. > > > > It sounds like Cappy might have fixed his gauge but broken some law of > > physics. Typical Cappy maneuver if you ask me. Today I shall have to > > see if he messed up Bernouli and Newton's, by seeing if my wing still > > generates enough lift to fly :-) > > > > Cappy, I'd appreciate it if you wouldn't break or damage physical laws > > that the rest of us use every day, just to get your gauges reading > > correctly; that's very selfish and won't be tolerated. > > > > -Stormy > > > > On 1/28/07, Ron Schreck wrote: > > > > > > > > Steve, > > > > > > Glad to hear you are back in the air. Actually, your problem and > > > solution makes perfect sense to me (Monday morning quarterbacking, > > > however). If your fuel and oil pressure sensors are mounted high on > the > > > firewall, it only makes sense that any air trapped in the lines will > > > never bleed out (down hill) without some help. True, the trapped air > > > may transfer some measure of pressure, but being much more > compressible > > > than a liquid it would certainly be a false reading. I think your > > > solution merits a mention on the RV list and perhaps a suggestion that > > > these sensors be mounted low on the firewall to avoid the problem > > > altogether. Nice work, Cappy! > > > > > > Smokey > > > > > > -----Original Message----- > > > From: owner-rvsoutheast-list-server@matronics.com > > > [mailto:owner-rvsoutheast-list-server@matronics.com] On > > Behalf Of Steve > > > Glasgow > > > Sent: Saturday, January 27, 2007 5:13 PM > > > To: SERV > > > Subject: RVSouthEast-List: Fuel Pressure Fixed > > > > > > > > > --> > > > > > > Turns out there was apparently air in the line to the > sender. Probably > > > from > > > lines being open on annual. > > > > > > I flew before doing the procedure below and the fuel pressure was all > > > over > > > the place. From 4 to 9.5 psi. > > > > > > Anyway here is what to do to get the air out. Disconnect wires from > > > fuel > > > sender. Loosen sender so it can be moved by hand. Keep sender hand > > > tight > > > and turn on electric pump. Now loosen sender till fuel comes out > around > > > the > > > pipe fitting. Then tighten to stop the fuel from leaking. Turn off > > > electric pump, secure sender and hook up wires. Done. From now on I > > > will > > > do this procedure whenever a fuel line is opened. > > > > > > I flew before doing this and the fuel pressure was all over the place. > > > >From > > > 4 to 9.5 psi. > > > > > > Cappy > > > > > > > > > > > > > > > > > > > > > -- > > > 1/26/2007 11:11 AM > > > > > > > > > -- > > > 1/27/2007 5:02 p; Features Subscriptions > > href="http://www.matronics.com/Navigator?RVSouthEast-List">http://www.mp > ; > > available via > > href="http://forums.matronics.com">http://forums.matronics.com > > > > > > > > > > > > > > -- This is an alternate email. Please continue to email me at james@nextupventures.com . ________________________________ Message 7 _____________________________________ Time: 06:31:18 AM PST US From: "Bill Boyd" Subject: Re: RVSouthEast-List: Fuel Pressure Fixed One never knows. Seems these transducers do have a troubled service history, though. Swaping them out usually fixes whatever problem one is posting to the list about :-) Steve's direct reading gauge will tell all when he gets it hooked in. -B On 1/28/07, James Clark wrote: > Consider this: Removing the "air" may have been the mechanism that removed > some other "trapped particle" that might have been affecting the transducer. > > James > > > On 1/28/07, Bill Boyd wrote: > > > > Yeah, I've been known to lose my position fix on the internet before... > > > > I'm wrestling with this and want to understand it. You raise one > > (calibration) point below: the pressure you read will be less than > > carb pressure by the height of the fluid column betwee the carb and > > the transducer. Not sure how many inches of gasoline column equal one > > p.s.i., but it varies with gasoline versus air because of the > > differing densities. Same reason a barometer made with mercury is > > only a few feet tall versus one with water at around 32 feet tall! > > > > The way I look at it, the pressure at my air tool is at the same value > > as at the compressor regulator (until I squeeze the trigger and air > > flow in the line causes a "voltage drop" - I'm talking about static > > pressure, such as we read in a fuel pressure line that dead-ends into > > a transducer). To me this demonstrates that air sends its pressure > > down the hose just like any other fluid, otherwise my pneumatic tools > > would not work. > > > > I still believe that when your fuel system pressurizes, everything in > > the system, even trapped air, comes up to the same pressure and should > > read as such on any transducer. If I'm mistaken, let me know; > > meanwhile my air tools still work just dandy on this exact principle. > > But as you say, I've been wrong before. > > > > I only belabor the point b/c I'm not convinced that this could have > > fixed the problem and you might need to keep investigating. > > > > -Stormy > > > > On 1/28/07, Steve Glasgow < willfly@carolina.rr.com> wrote: > > > > > > > > > What about compressibility of a gas verses a liquid. Water pipes have > air > > > trapped in them all the time to prevent hammer effect. The pressure > sender > > > is up the line not down the line. Pressure is correct at the engine, > just > > > not the pressure sender which is way above the carburetor. You may be > > > correct if the sender is plumbed at the carburetor but mine isn't. > All I > > > know is it worked. No more oscillating fuel pressure. > > > > > > Stormy, are you giving us bad coordinates again? > > > > > > Love Cappy > > > > > > ----- Original Message ----- > > > From: Bill Boyd > > > To: rvsoutheast-list@matronics.com > > > Sent: Sunday, January 28, 2007 8:05 AM > > > Subject: Re: RVSouthEast-List: Fuel Pressure Fixed > > > > sportav8r@gmail.com> > > > > > > Smokey, > > > > > > I think the trapped air compresses until it reaches equilib. and then > > > transmits all the pressure on down the line... in doing so it will > > > tend to dampen any pulses (soften the water-hammer effect, > > > what-have-you) but I think all the pressure will show up at the > > > transducer. Enlighten me if I'm overlooking the obvious. > > > > > > It sounds like Cappy might have fixed his gauge but broken some law of > > > physics. Typical Cappy maneuver if you ask me. Today I shall have to > > > see if he messed up Bernouli and Newton's, by seeing if my wing still > > > generates enough lift to fly :-) > > > > > > Cappy, I'd appreciate it if you wouldn't break or damage physical laws > > > that the rest of us use every day, just to get your gauges reading > > > correctly; that's very selfish and won't be tolerated. > > > > > > -Stormy > > > > > > On 1/28/07, Ron Schreck wrote: > > > > > > > > > > > Steve, > > > > > > > > Glad to hear you are back in the air. Actually, your problem and > > > > solution makes perfect sense to me (Monday morning quarterbacking, > > > > however). If your fuel and oil pressure sensors are mounted high on > the > > > > firewall, it only makes sense that any air trapped in the lines will > > > > never bleed out (down hill) without some help. True, the trapped air > > > > may transfer some measure of pressure, but being much more > compressible > > > > than a liquid it would certainly be a false reading. I think your > > > > solution merits a mention on the RV list and perhaps a suggestion that > > > > these sensors be mounted low on the firewall to avoid the problem > > > > altogether. Nice work, Cappy! > > > > > > > > Smokey > > > > > > > > -----Original Message----- > > > > From: owner-rvsoutheast-list-server@matronics.com > > > > [mailto:owner-rvsoutheast-list-server@matronics.com ] > On > > > Behalf Of Steve > > > > Glasgow > > > > Sent: Saturday, January 27, 2007 5:13 PM > > > > To: SERV > > > > Subject: RVSouthEast-List: Fuel Pressure Fixed > > > > > > > > > > > > --> > > > > > > > > Turns out there was apparently air in the line to the sender. > Probably > > > > from > > > > lines being open on annual. > > > > > > > > I flew before doing the procedure below and the fuel pressure was all > > > > over > > > > the place. From 4 to 9.5 psi. > > > > > > > > Anyway here is what to do to get the air out. Disconnect wires from > > > > fuel > > > > sender. Loosen sender so it can be moved by hand. Keep sender hand > > > > tight > > > > and turn on electric pump. Now loosen sender till fuel comes out > around > > > > the > > > > pipe fitting. Then tighten to stop the fuel from leaking. Turn off > > > > electric pump, secure sender and hook up wires. Done. From now on I > > > > will > > > > do this procedure whenever a fuel line is opened. > > > > > > > > I flew before doing this and the fuel pressure was all over the place. > > > > >From > > > > 4 to 9.5 psi. > > > > > > > > Cappy > > > > > > > > > > > > > > > > > > > > > > > > > > > > -- > > > > 1/26/2007 11:11 AM > > > > > > > > > > > > -- > > > > 1/27/2007 5:02 p; Features Subscriptions > > > href=" > http://www.matronics.com/Navigator?RVSouthEast-List">http://www.mp; > > > available via > > > href="http://forums.matronics.com > > > > > > > > > -- > This is an alternate email. Please continue to email me at > james@nextupventures.com . > > ________________________________ Message 8 _____________________________________ Time: 07:25:46 AM PST US From: "Ed Anderson" Subject: bubbles and pressure was : RVSouthEast-List: Fuel Pressure Fixed I think you are correct, Cappy. There are several states of gas that can exist in a liquid, some which cause worst effects than others, but in any case, they all appear to affect pressure measurements in a line to various degrees. Although, the attached refers to air in a hydraulic system the effects are the same in a pressurized fuel line. Note that bubbles can cause changes in head pressure as well as erroneous measurements and response delays. Ed ----- Original Message ----- From: Steve Glasgow To: rvsoutheast-list@matronics.com Sent: Sunday, January 28, 2007 8:27 AM Subject: Re: RVSouthEast-List: Fuel Pressure Fixed What about compressibility of a gas verses a liquid. Water pipes have air trapped in them all the time to prevent hammer effect. The pressure sender is up the line not down the line. Pressure is correct at the engine, just not the pressure sender which is way above the carburetor. You may be correct if the sender is plumbed at the carburetor but mine isn't. All I know is it worked. No more oscillating fuel pressure. Stormy, are you giving us bad coordinates again? Love Cappy ----- Original Message ----- From: Bill Boyd To: rvsoutheast-list@matronics.com Sent: Sunday, January 28, 2007 8:05 AM Subject: Re: RVSouthEast-List: Fuel Pressure Fixed Smokey, I think the trapped air compresses until it reaches equilib. and then transmits all the pressure on down the line... in doing so it will tend to dampen any pulses (soften the water-hammer effect, what-have-you) but I think all the pressure will show up at the transducer. Enlighten me if I'm overlooking the obvious. It sounds like Cappy might have fixed his gauge but broken some law of physics. Typical Cappy maneuver if you ask me. Today I shall have to see if he messed up Bernouli and Newton's, by seeing if my wing still generates enough lift to fly :-) Cappy, I'd appreciate it if you wouldn't break or damage physical laws that the rest of us use every day, just to get your gauges reading correctly; that's very selfish and won't be tolerated. -Stormy On 1/28/07, Ron Schreck wrote: > > Steve, > > Glad to hear you are back in the air. Actually, your problem and > solution makes perfect sense to me (Monday morning quarterbacking, > however). If your fuel and oil pressure sensors are mounted high on the > firewall, it only makes sense that any air trapped in the lines will > never bleed out (down hill) without some help. True, the trapped air > may transfer some measure of pressure, but being much more compressible > than a liquid it would certainly be a false reading. I think your > solution merits a mention on the RV list and perhaps a suggestion that > these sensors be mounted low on the firewall to avoid the problem > altogether. Nice work, Cappy! > > Smokey > > -----Original Message----- > From: owner-rvsoutheast-list-server@matronics.com > [mailto:owner-rvsoutheast-list-server@matronics.com] On Behalf Of Steve > Glasgow > Sent: Saturday, January 27, 2007 5:13 PM > To: SERV > Subject: RVSouthEast-List: Fuel Pressure Fixed > > > --> > > Turns out there was apparently air in the line to the sender. Probably > from > lines being open on annual. > > I flew before doing the procedure below and the fuel pressure was all > over > the place. From 4 to 9.5 psi. > > Anyway here is what to do to get the air out. Disconnect wires from > fuel > sender. Loosen sender so it can be moved by hand. Keep sender hand > tight > and turn on electric pump. Now loosen sender till fuel comes out around > the > pipe fitting. Then tighten to stop the fuel from leaking. Turn off > electric pump, secure sender and hook up wires. Done. From now on I > will > do this procedure whenever a fuel line is opened. > > I flew before doing this and the fuel pressure was all over the place. > >From > 4 to 9.5 psi. > > Cappy > > > > > > > -- > 1/26/2007 11:11 AM > > > -- > 1/27/2007 5:02 p; Features Subscriptions href="http://www.matronics.com/Navigator?RVSouthEast-List">http://www.m p; available via href="http://forums.matronics.com">http://forums.matronics.com ________________________________ Message 9 _____________________________________ Time: 10:24:39 AM PST US From: "Bill Boyd" Subject: Re: bubbles and pressure was : RVSouthEast-List: Fuel Pressure Fixed Okay, I learned something today. Given what I know now, I'm glad mine have worked well all these years without any bleeding that I can recall doing. -Stormy On 1/28/07, Ed Anderson wrote: > > I think you are correct, Cappy. There are several states of gas that can > exist in a liquid, some which cause worst effects than others, but in any > case, they all appear to affect pressure measurements in a line to various > degrees. Although, the attached refers to air in a hydraulic system the > effects are the same in a pressurized fuel line. Note that bubbles can > cause changes in head pressure as well as erroneous measurements and > response delays. > > Ed > > > ----- Original Message ----- > *From:* Steve Glasgow > *To:* rvsoutheast-list@matronics.com > *Sent:* Sunday, January 28, 2007 8:27 AM > *Subject:* Re: RVSouthEast-List: Fuel Pressure Fixed > > What about compressibility of a gas verses a liquid. Water pipes have air > trapped in them all the time to prevent hammer effect. The pressure sender > is up the line not down the line. Pressure is correct at the engine, just > not the pressure sender which is way above the carburetor. You may be > correct if the sender is plumbed at the carburetor but mine isn't. All I > know is it worked. No more oscillating fuel pressure. > > Stormy, are you giving us bad coordinates again? > > Love Cappy > > ----- Original Message ----- > *From:* Bill Boyd > *To:* rvsoutheast-list@matronics.com > *Sent:* Sunday, January 28, 2007 8:05 AM > *Subject:* Re: RVSouthEast-List: Fuel Pressure Fixed > > > Smokey, > > I think the trapped air compresses until it reaches equilib. and then > transmits all the pressure on down the line... in doing so it will > tend to dampen any pulses (soften the water-hammer effect, > what-have-you) but I think all the pressure will show up at the > transducer. Enlighten me if I'm overlooking the obvious. > > It sounds like Cappy might have fixed his gauge but broken some law of > physics. Typical Cappy maneuver if you ask me. Today I shall have to > see if he messed up Bernouli and Newton's, by seeing if my wing still > generates enough lift to fly :-) > > Cappy, I'd appreciate it if you wouldn't break or damage physical laws > that the rest of us use every day, just to get your gauges reading > correctly; that's very selfish and won't be tolerated. > > -Stormy > > On 1/28/07, Ron Schreck wrote: > ronschreck@alltel.net> > > > > Steve, > > > > Glad to hear you are back in the air. Actually, your problem and > > solution makes perfect sense to me (Monday morning quarterbacking, > > however). If your fuel and oil pressure sensors are mounted high on the > > firewall, it only makes sense that any air trapped in the lines will > > never bleed out (down hill) without some help. True, the trapped air > > may transfer some measure of pressure, but being much more compressible > > than a liquid it would certainly be a false reading. I think your > > solution merits a mention on the RV list and perhaps a suggestion that > > these sensors be mounted low on the firewall to avoid the problem > > altogether. Nice work, Cappy! > > > > Smokey > > > > -----Original Message----- > > From: owner-rvsoutheast-list-server@matronics.com > > [mailto:owner-rvsoutheast-list-server@matronics.com] On Behalf Of Steve > > Glasgow > > Sent: Saturday, January 27, 2007 5:13 PM > > To: SERV > > Subject: RVSouthEast-List: Fuel Pressure Fixed > > > > > > --> > > > > Turns out there was apparently air in the line to the sender. Probably > > from > > lines being open on annual. > > > > I flew before doing the procedure below and the fuel pressure was all > > over > > the place. From 4 to 9.5 psi. > > > > Anyway here is what to do to get the air out. Disconnect wires from > > fuel > > sender. Loosen sender so it can be moved by hand. Keep sender hand > > tight > > and turn on electric pump. Now loosen sender till fuel comes out around > > the > > pipe fitting. Then tighten to stop the fuel from leaking. Turn off > > electric pump, secure sender and hook up wires. Done. From now on I > > will > > do this procedure whenever a fuel line is opened. > > > > I flew before doing this and the fuel pressure was all over the place. > > >From > > 4 to 9.5 psi. > > > > Cappy > > > > > > > > > > > > > > -- > > 1/26/2007 11:11 AM > > > > > > -- > > 1/27/2007 5:02 p; Features Subscriptions href=" > http://www.matronics.com/Navigator?RVSouthEast-List">http://www.mp; > available via href="http://forums.matronics.com"> > http://forums.matronics.com* > * > > * > > href="http://www.matronics.com/Navigator?RVSouthEast-List">http://www.matronics.com/Navigator?RVSouthEast-List > href="http://forums.matronics.com">http://forums.matronics.com > * > > ________________________________ Message 10 ____________________________________ Time: 10:57:46 AM PST US From: "Steve Glasgow" Subject: Re: bubbles and pressure was : RVSouthEast-List: Fuel Pressure Fixed Thanks ED. I knew I liked you. I think it all has to do with where the sender is located Stormy. Mine is very high on the firewall. Cappy ----- Original Message ----- From: Bill Boyd To: rvsoutheast-list@matronics.com Sent: Sunday, January 28, 2007 1:24 PM Subject: Re: bubbles and pressure was : RVSouthEast-List: Fuel Pressure Fixed Okay, I learned something today. Given what I know now, I'm glad mine have worked well all these years without any bleeding that I can recall doing. -Stormy On 1/28/07, Ed Anderson wrote: I think you are correct, Cappy. There are several states of gas that can exist in a liquid, some which cause worst effects than others, but in any case, they all appear to affect pressure measurements in a line to various degrees. Although, the attached refers to air in a hydraulic system the effects are the same in a pressurized fuel line. Note that bubbles can cause changes in head pressure as well as erroneous measurements and response delays. Ed ----- Original Message ----- From: Steve Glasgow To: rvsoutheast-list@matronics.com Sent: Sunday, January 28, 2007 8:27 AM Subject: Re: RVSouthEast-List: Fuel Pressure Fixed What about compressibility of a gas verses a liquid. Water pipes have air trapped in them all the time to prevent hammer effect. The pressure sender is up the line not down the line. Pressure is correct at the engine, just not the pressure sender which is way above the carburetor. You may be correct if the sender is plumbed at the carburetor but mine isn't. All I know is it worked. No more oscillating fuel pressure. Stormy, are you giving us bad coordinates again? Love Cappy ----- Original Message ----- From: Bill Boyd To: rvsoutheast-list@matronics.com Sent: Sunday, January 28, 2007 8:05 AM Subject: Re: RVSouthEast-List: Fuel Pressure Fixed Smokey, I think the trapped air compresses until it reaches equilib. and then transmits all the pressure on down the line... in doing so it will tend to dampen any pulses (soften the water-hammer effect, what-have-you) but I think all the pressure will show up at the transducer. Enlighten me if I'm overlooking the obvious. It sounds like Cappy might have fixed his gauge but broken some law of physics. Typical Cappy maneuver if you ask me. Today I shall have to see if he messed up Bernouli and Newton's, by seeing if my wing still generates enough lift to fly :-) Cappy, I'd appreciate it if you wouldn't break or damage physical laws that the rest of us use every day, just to get your gauges reading correctly; that's very selfish and won't be tolerated. -Stormy On 1/28/07, Ron Schreck wrote: > > Steve, > > Glad to hear you are back in the air. Actually, your problem and > solution makes perfect sense to me (Monday morning quarterbacking, > however). If your fuel and oil pressure sensors are mounted high on the > firewall, it only makes sense that any air trapped in the lines will > never bleed out (down hill) without some help. True, the trapped air > may transfer some measure of pressure, but being much more compressible > than a liquid it would certainly be a false reading. I think your > solution merits a mention on the RV list and perhaps a suggestion that > these sensors be mounted low on the firewall to avoid the problem > altogether. Nice work, Cappy! > > Smokey > > -----Original Message----- > From: owner-rvsoutheast-list-server@matronics.com > [mailto:owner-rvsoutheast-list-server@matronics.com] On Behalf Of Steve > Glasgow > Sent: Saturday, January 27, 2007 5:13 PM > To: SERV > Subject: RVSouthEast-List: Fuel Pressure Fixed > > > --> > > Turns out there was apparently air in the line to the sender. Probably > from > lines being open on annual. > > I flew before doing the procedure below and the fuel pressure was all > over > the place. From 4 to 9.5 psi. > > Anyway here is what to do to get the air out. Disconnect wires from > fuel > sender. Loosen sender so it can be moved by hand. Keep sender hand > tight > and turn on electric pump. Now loosen sender till fuel comes out around > the > pipe fitting. Then tighten to stop the fuel from leaking. Turn off > electric pump, secure sender and hook up wires. Done. From now on I > will > do this procedure whenever a fuel line is opened. > > I flew before doing this and the fuel pressure was all over the place. > >From > 4 to 9.5 psi. > > Cappy > > > > > > > -- > 1/26/2007 11:11 AM > > > -- > 1/27/2007 5:02 p; Features Subscriptions href="http://www.matronics.com/Navigator?RVSouthEast-List"> http://www.mp; available via href="http://forums.matronics.com"> http://forums.matronics.com href="http://www.matronics.com/Navigator?RVSouthEast-List"> http://www.matronics.com/Navigator?RVSouthEast-List href="http://forums.matronics.com"> http://forums.matronics.com ________________________________ Message 11 ____________________________________ Time: 06:22:44 PM PST US From: "Bill Boyd" Subject: Re: bubbles and pressure was : RVSouthEast-List: Fuel Pressure Fixed As are mine; as high as possible. 625 glitch-free hours but who's counting ;-) On 1/28/07, Steve Glasgow wrote: > > Thanks ED. I knew I liked you. I think it all has to do with where the > sender is located Stormy. Mine is very high on the firewall. > > Cappy > > ----- Original Message ----- > *From:* Bill Boyd > *To:* rvsoutheast-list@matronics.com > *Sent:* Sunday, January 28, 2007 1:24 PM > *Subject:* Re: bubbles and pressure was : RVSouthEast-List: Fuel Pressure > Fixed > > Okay, I learned something today. > > Given what I know now, I'm glad mine have worked well all these years > without any bleeding that I can recall doing. > > -Stormy > > On 1/28/07, Ed Anderson wrote: > > > > I think you are correct, Cappy. There are several states of gas that > > can exist in a liquid, some which cause worst effects than others, but in > > any case, they all appear to affect pressure measurements in a line to > > various degrees. Although, the attached refers to air in a hydraulic system > > the effects are the same in a pressurized fuel line. Note that bubbles can > > cause changes in head pressure as well as erroneous measurements and > > response delays. > > > > Ed > > > > > > > > > > > > ----- Original Message ----- > > *From:* Steve Glasgow > > *To:* rvsoutheast-list@matronics.com > > *Sent:* Sunday, January 28, 2007 8:27 AM > > *Subject:* Re: RVSouthEast-List: Fuel Pressure Fixed > > > > What about compressibility of a gas verses a liquid. Water pipes have > > air trapped in them all the time to prevent hammer effect. The pressure > > sender is up the line not down the line. Pressure is correct at the engine, > > just not the pressure sender which is way above the carburetor. You may > > be correct if the sender is plumbed at the carburetor but mine isn't. All > > I know is it worked. No more oscillating fuel pressure. > > > > Stormy, are you giving us bad coordinates again? > > > > Love Cappy > > > > ----- Original Message ----- > > *From:* Bill Boyd > > *To:* rvsoutheast-list@matronics.com > > *Sent:* Sunday, January 28, 2007 8:05 AM > > *Subject:* Re: RVSouthEast-List: Fuel Pressure Fixed > > > > > > > > Smokey, > > > > I think the trapped air compresses until it reaches equilib. and then > > transmits all the pressure on down the line... in doing so it will > > tend to dampen any pulses (soften the water-hammer effect, > > what-have-you) but I think all the pressure will show up at the > > transducer. Enlighten me if I'm overlooking the obvious. > > > > It sounds like Cappy might have fixed his gauge but broken some law of > > physics. Typical Cappy maneuver if you ask me. Today I shall have to > > see if he messed up Bernouli and Newton's, by seeing if my wing still > > generates enough lift to fly :-) > > > > Cappy, I'd appreciate it if you wouldn't break or damage physical laws > > that the rest of us use every day, just to get your gauges reading > > correctly; that's very selfish and won't be tolerated. > > > > -Stormy > > > > On 1/28/07, Ron Schreck wrote: > > ronschreck@alltel.net> > > > > > > Steve, > > > > > > Glad to hear you are back in the air. Actually, your problem and > > > solution makes perfect sense to me (Monday morning quarterbacking, > > > however). If your fuel and oil pressure sensors are mounted high on > > the > > > firewall, it only makes sense that any air trapped in the lines will > > > never bleed out (down hill) without some help. True, the trapped air > > > may transfer some measure of pressure, but being much more > > compressible > > > than a liquid it would certainly be a false reading. I think your > > > solution merits a mention on the RV list and perhaps a suggestion that > > > these sensors be mounted low on the firewall to avoid the problem > > > altogether. Nice work, Cappy! > > > > > > Smokey > > > > > > -----Original Message----- > > > From: owner-rvsoutheast-list-server@matronics.com > > > [mailto:owner-rvsoutheast-list-server@matronics.com] On Behalf Of > > Steve > > > Glasgow > > > Sent: Saturday, January 27, 2007 5:13 PM > > > To: SERV > > > Subject: RVSouthEast-List: Fuel Pressure Fixed > > > > > > > > > --> > > > > > > Turns out there was apparently air in the line to the sender. > > Probably > > > from > > > lines being open on annual. > > > > > > I flew before doing the procedure below and the fuel pressure was all > > > over > > > the place. From 4 to 9.5 psi. > > > > > > Anyway here is what to do to get the air out. Disconnect wires from > > > fuel > > > sender. Loosen sender so it can be moved by hand. Keep sender hand > > > tight > > > and turn on electric pump. Now loosen sender till fuel comes out > > around > > > the > > > pipe fitting. Then tighten to stop the fuel from leaking. Turn off > > > electric pump, secure sender and hook up wires. Done. From now on I > > > will > > > do this procedure whenever a fuel line is opened. > > > > > > I flew before doing this and the fuel pressure was all over the place. > > > >From > > > 4 to 9.5 psi. > > > > > > Cappy > > > > > > > > > > > > > > > > > > > > > -- > > > 1/26/2007 11:11 AM > > > > > > > > > -- > > > 1/27/2007 5:02 p; Features Subscriptions href=" > > http://www.matronics.com/Navigator?RVSouthEast-List"> http://www.mp; > > available via href="http://forums.matronics.com">http://forums.matronics.com > > * > > * > > > > * > > > > href="http://www.matronics.com/Navigator?RVSouthEast-List"> > > http://www.matronics.com/Navigator?RVSouthEast-List > > href="http://forums.matronics.com"> > > http://forums.matronics.com > > * > > > > > ________________________________ Message 12 ____________________________________ Time: 06:28:47 PM PST US From: "Bill Boyd" Subject: Re: bubbles and pressure was : RVSouthEast-List: Fuel Pressure Fixed Response delays I'll buy, Ed. In fact, I'll take water-hammer dampeners for $50, please ;-) There may be as many "states of gas that can exist in a liquid" as there are ways to leave your lover, but they are all at the same pressure if they're confined in the same hose - or I live in a parallel universe (a possibility I will disregard for the sake of continuing to fly with you fine friends ;-) -Stormy On 1/28/07, Ed Anderson wrote: > > I think you are correct, Cappy. There are several states of gas that can > exist in a liquid, some which cause worst effects than others, but in any > case, they all appear to affect pressure measurements in a line to various > degrees. Although, the attached refers to air in a hydraulic system the > effects are the same in a pressurized fuel line. Note that bubbles can > cause changes in head pressure as well as erroneous measurements and > response delays. > > Ed > > > ----- Original Message ----- > *From:* Steve Glasgow > *To:* rvsoutheast-list@matronics.com > *Sent:* Sunday, January 28, 2007 8:27 AM > *Subject:* Re: RVSouthEast-List: Fuel Pressure Fixed > > What about compressibility of a gas verses a liquid. Water pipes have air > trapped in them all the time to prevent hammer effect. The pressure sender > is up the line not down the line. Pressure is correct at the engine, just > not the pressure sender which is way above the carburetor. You may be > correct if the sender is plumbed at the carburetor but mine isn't. All I > know is it worked. No more oscillating fuel pressure. > > Stormy, are you giving us bad coordinates again? > > Love Cappy > > ----- Original Message ----- > *From:* Bill Boyd > *To:* rvsoutheast-list@matronics.com > *Sent:* Sunday, January 28, 2007 8:05 AM > *Subject:* Re: RVSouthEast-List: Fuel Pressure Fixed > > > Smokey, > > I think the trapped air compresses until it reaches equilib. and then > transmits all the pressure on down the line... in doing so it will > tend to dampen any pulses (soften the water-hammer effect, > what-have-you) but I think all the pressure will show up at the > transducer. Enlighten me if I'm overlooking the obvious. > > It sounds like Cappy might have fixed his gauge but broken some law of > physics. Typical Cappy maneuver if you ask me. Today I shall have to > see if he messed up Bernouli and Newton's, by seeing if my wing still > generates enough lift to fly :-) > > Cappy, I'd appreciate it if you wouldn't break or damage physical laws > that the rest of us use every day, just to get your gauges reading > correctly; that's very selfish and won't be tolerated. > > -Stormy > > On 1/28/07, Ron Schreck wrote: > ronschreck@alltel.net> > > > > Steve, > > > > Glad to hear you are back in the air. Actually, your problem and > > solution makes perfect sense to me (Monday morning quarterbacking, > > however). If your fuel and oil pressure sensors are mounted high on the > > firewall, it only makes sense that any air trapped in the lines will > > never bleed out (down hill) without some help. True, the trapped air > > may transfer some measure of pressure, but being much more compressible > > than a liquid it would certainly be a false reading. I think your > > solution merits a mention on the RV list and perhaps a suggestion that > > these sensors be mounted low on the firewall to avoid the problem > > altogether. Nice work, Cappy! > > > > Smokey > > > > -----Original Message----- > > From: owner-rvsoutheast-list-server@matronics.com > > [mailto:owner-rvsoutheast-list-server@matronics.com] On Behalf Of Steve > > Glasgow > > Sent: Saturday, January 27, 2007 5:13 PM > > To: SERV > > Subject: RVSouthEast-List: Fuel Pressure Fixed > > > > > > --> > > > > Turns out there was apparently air in the line to the sender. Probably > > from > > lines being open on annual. > > > > I flew before doing the procedure below and the fuel pressure was all > > over > > the place. From 4 to 9.5 psi. > > > > Anyway here is what to do to get the air out. Disconnect wires from > > fuel > > sender. Loosen sender so it can be moved by hand. Keep sender hand > > tight > > and turn on electric pump. Now loosen sender till fuel comes out around > > the > > pipe fitting. Then tighten to stop the fuel from leaking. Turn off > > electric pump, secure sender and hook up wires. Done. From now on I > > will > > do this procedure whenever a fuel line is opened. > > > > I flew before doing this and the fuel pressure was all over the place. > > >From > > 4 to 9.5 psi. > > > > Cappy > > > > > > > > > > > > > > -- > > 1/26/2007 11:11 AM > > > > > > -- > > 1/27/2007 5:02 p; Features Subscriptions href=" > http://www.matronics.com/Navigator?RVSouthEast-List">http://www.mp; > available via href="http://forums.matronics.com"> > http://forums.matronics.com* > * > > * > > href="http://www.matronics.com/Navigator?RVSouthEast-List">http://www.matronics.com/Navigator?RVSouthEast-List > href="http://forums.matronics.com">http://forums.matronics.com > * > > ________________________________ Message 13 ____________________________________ Time: 07:48:19 PM PST US From: "Ed Anderson" Subject: Re: bubbles and pressure was : RVSouthEast-List: Fuel Pressure Fixed I agree, Stormy, if you have a steady state condition. However, when the system environment is not static but dynamic then you can indeed have fluctuation states that cause the state in one part of the system to be different than another part. Consider two rail road cars separated by a untearable bag of air,each car with a force measuring instrument (after all pressure is simply force over an area, right?). Then back an engine into the first car at some rate of speed. The first car will "feel" the impact essential instantaneously over its entire length and the force measuring device on the first car will register the force of the impact. However, at the same instant the force measuring sensor on the second car will register zero force. It will continue to register zero force until the pressure inside the air bag has increased sufficiently ( due to the compression forces) that the compressed air is able to transmit some force to the second car. Yes, eventually, the second car will measure the same force as the first car - but not instantaneous, there will be a delay. Now repeated back up the engine and ram the cars again and again and you have a rather chaotic and dynamic system with the air compressing, collapsing, rebounding, etc. Therefore, you can have two different sections of the liquid (separated by bubble(s)) that see difference forces and therefore pressures varying in a dynamic manner. In a real fuel line the situation is considerably more dynamic than my example. In a fuel line with multiple bubbles the situation can be complex. You have a pump that may be creating bubbles through caviation, you will have some amount of air bubble being re-absorbed back into the fluid, you have bubbles being created by pressure drops through fittings, temperature increases, etc. You may even have a leak that permits air into the system. So depending on the level your are viewing it at -what may appear to be a steady state system is its anything but a steady state system. Air in fluid lines is generally not a good thing - just how bad the effect can - depends on a number of variables. But, if you have had no problems - then I certainly wouldn't worry about all those little bubbles {:>) my 0.02 and I'm off to bed Ed ----- Original Message ----- From: Bill Boyd To: rvsoutheast-list@matronics.com Sent: Sunday, January 28, 2007 9:28 PM Subject: Re: bubbles and pressure was : RVSouthEast-List: Fuel Pressure Fixed Response delays I'll buy, Ed. In fact, I'll take water-hammer dampeners for $50, please ;-) There may be as many "states of gas that can exist in a liquid" as there are ways to leave your lover, but they are all at the same pressure if they're confined in the same hose - or I live in a parallel universe (a possibility I will disregard for the sake of continuing to fly with you fine friends ;-) -Stormy On 1/28/07, Ed Anderson wrote: I think you are correct, Cappy. There are several states of gas that can exist in a liquid, some which cause worst effects than others, but in any case, they all appear to affect pressure measurements in a line to various degrees. Although, the attached refers to air in a hydraulic system the effects are the same in a pressurized fuel line. Note that bubbles can cause changes in head pressure as well as erroneous measurements and response delays. Ed ----- Original Message ----- From: Steve Glasgow To: rvsoutheast-list@matronics.com Sent: Sunday, January 28, 2007 8:27 AM Subject: Re: RVSouthEast-List: Fuel Pressure Fixed What about compressibility of a gas verses a liquid. Water pipes have air trapped in them all the time to prevent hammer effect. The pressure sender is up the line not down the line. Pressure is correct at the engine, just not the pressure sender which is way above the carburetor. You may be correct if the sender is plumbed at the carburetor but mine isn't. All I know is it worked. No more oscillating fuel pressure. Stormy, are you giving us bad coordinates again? Love Cappy ----- Original Message ----- From: Bill Boyd To: rvsoutheast-list@matronics.com Sent: Sunday, January 28, 2007 8:05 AM Subject: Re: RVSouthEast-List: Fuel Pressure Fixed Smokey, I think the trapped air compresses until it reaches equilib. and then transmits all the pressure on down the line... in doing so it will tend to dampen any pulses (soften the water-hammer effect, what-have-you) but I think all the pressure will show up at the transducer. Enlighten me if I'm overlooking the obvious. It sounds like Cappy might have fixed his gauge but broken some law of physics. Typical Cappy maneuver if you ask me. Today I shall have to see if he messed up Bernouli and Newton's, by seeing if my wing still generates enough lift to fly :-) Cappy, I'd appreciate it if you wouldn't break or damage physical laws that the rest of us use every day, just to get your gauges reading correctly; that's very selfish and won't be tolerated. -Stormy On 1/28/07, Ron Schreck wrote: > > Steve, > > Glad to hear you are back in the air. Actually, your problem and > solution makes perfect sense to me (Monday morning quarterbacking, > however). If your fuel and oil pressure sensors are mounted high on the > firewall, it only makes sense that any air trapped in the lines will > never bleed out (down hill) without some help. True, the trapped air > may transfer some measure of pressure, but being much more compressible > than a liquid it would certainly be a false reading. I think your > solution merits a mention on the RV list and perhaps a suggestion that > these sensors be mounted low on the firewall to avoid the problem > altogether. Nice work, Cappy! > > Smokey > > -----Original Message----- > From: owner-rvsoutheast-list-server@matronics.com > [mailto:owner-rvsoutheast-list-server@matronics.com] On Behalf Of Steve > Glasgow > Sent: Saturday, January 27, 2007 5:13 PM > To: SERV > Subject: RVSouthEast-List: Fuel Pressure Fixed > > > --> > > Turns out there was apparently air in the line to the sender. Probably > from > lines being open on annual. > > I flew before doing the procedure below and the fuel pressure was all > over > the place. From 4 to 9.5 psi. > > Anyway here is what to do to get the air out. Disconnect wires from > fuel > sender. Loosen sender so it can be moved by hand. Keep sender hand > tight > and turn on electric pump. Now loosen sender till fuel comes out around > the > pipe fitting. Then tighten to stop the fuel from leaking. Turn off > electric pump, secure sender and hook up wires. Done. From now on I > will > do this procedure whenever a fuel line is opened. > > I flew before doing this and the fuel pressure was all over the place. > >From > 4 to 9.5 psi. > > Cappy > > > > > > > -- > 1/26/2007 11:11 AM > > > -- > 1/27/2007 5:02 p; Features Subscriptions href="http://www.matronics.com/Navigator?RVSouthEast-List"> http://www.mp; available via href="http://forums.matronics.com"> http://forums.matronics.com href="http://www.matronics.com/Navigator?RVSouthEast-List"> http://www.matronics.com/Navigator?RVSouthEast-List href="http://forums.matronics.com"> http://forums.matronics.com ------------------------------------------------------------------------------------- Other Matronics Email List Services ------------------------------------------------------------------------------------- Post A New Message rvsoutheast-list@matronics.com UN/SUBSCRIBE http://www.matronics.com/subscription List FAQ http://www.matronics.com/FAQ/RVSouthEast-List.htm Web Forum Interface To Lists http://forums.matronics.com Matronics List Wiki http://wiki.matronics.com Full Archive Search Engine http://www.matronics.com/search 7-Day List Browse http://www.matronics.com/browse/rvsoutheast-list Browse Digests http://www.matronics.com/digest/rvsoutheast-list Browse Other Lists http://www.matronics.com/browse Live Online Chat! http://www.matronics.com/chat Archive Downloading http://www.matronics.com/archives Photo Share http://www.matronics.com/photoshare Other Email Lists http://www.matronics.com/emaillists Contributions http://www.matronics.com/contribution ------------------------------------------------------------------------------------- These Email List Services are sponsored solely by Matronics and through the generous Contributions of its members.