Today's Message Index:
----------------------
1. 07:30 AM - engine loping (thomas sargent)
2. 08:24 AM - Re: engine loping (Ralph E. Capen)
3. 08:38 AM - FW: f b 8 C (russell parr)
4. 08:45 AM - Re: capacitive fuel probes (was: engine loping) (Matt Dralle)
5. 08:55 AM - Re: engine loping ()
6. 09:22 AM - Re: engine loping (thomas sargent)
7. 09:28 AM - Re: engine loping (Jim Jewell)
8. 01:31 PM - Re: Re: capacitive fuel probes (was: engine loping) (thomas sargent)
9. 02:37 PM - Re: engine loping (Ralph E. Capen)
10. 03:04 PM - Re: engine loping (Carl Froehlich)
11. 03:58 PM - Re: engine loping (Deems Davis)
12. 04:09 PM - Re: engine loping (thomas sargent)
13. 04:15 PM - Re: Re: capacitive fuel probes (was: engine loping) (thomas sargent)
14. 04:31 PM - Re: engine loping (Bruce Bell)
15. 05:14 PM - Re: Re: capacitive fuel probes (was: engine loping) (Matt Dralle)
16. 05:50 PM - Re: Re: capacitive fuel probes (was: engine loping) (Dan Bergeron)
17. 07:20 PM - Re: Re: capacitive fuel probes (was: engine loping) (thomas sargent)
18. 09:45 PM - Re: engine loping (David Cudney)
19. 11:19 PM - Re: engine loping (thomas sargent)
Message 1
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All I have to do to be ready for my DAR inspection is to calibrate my
capacitive fuel probes. I taxied from the hangar to the fuel pumps (a few
hundred yards) on half a gallon of gas and then filled the left tank. The
engine ran OK on the way out. The plane has about an hour on it taxiing and
the engine has always run smoothly. On the way back from the pumps with the
left tank completely full, the engine wouldn't run at a steady speed. It
kept dropping RPM with a period of about 2 seconds. If I tried to make it
idle it would almost stop when the RPMs dropped. I tried changing the
mixture and running on one or the other ignition, to no effect. It seems
like a fuel supply issue. I didn't try turning on the electric boost pump
(I have AFP fuel injection). I guess I'll try that tomorrow.
I can't imagine how filling the tank could have any effect, so this is
probably just a coincidence. Any suggestions?
--
Tom Sargent
Message 2
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| Subject: | Re: engine loping |
Tom,
How long did it run before you shut it down at the fuel pump? How long was it
shut down to refuel? Did you run the purge system before restart? Do you have
a cooling shroud around your fuel pump?
What size injector restrictors do you have? I have swapped out the stock .028
for .024 and turned my idle mixture two lands rich - that helped my hot running
quite a bit. Additionally, after a hot restart, mine lopes a bit too at lower
idles - even with the boost pump on.
According to what I've read, it's worse with SJ cowls and plenums.
Ralph
RV6A N822AR @ N06 65hrs
AFP, SJ Cowl/plenum, LASAR ignition
-----Original Message-----
>From: thomas sargent <sarg314@gmail.com>
>Sent: May 23, 2010 10:26 AM
>To: rv-list <rv-list@matronics.com>
>Subject: RV-List: engine loping
>
>All I have to do to be ready for my DAR inspection is to calibrate my
>capacitive fuel probes. I taxied from the hangar to the fuel pumps (a few
>hundred yards) on half a gallon of gas and then filled the left tank. The
>engine ran OK on the way out. The plane has about an hour on it taxiing and
>the engine has always run smoothly. On the way back from the pumps with the
>left tank completely full, the engine wouldn't run at a steady speed. It
>kept dropping RPM with a period of about 2 seconds. If I tried to make it
>idle it would almost stop when the RPMs dropped. I tried changing the
>mixture and running on one or the other ignition, to no effect. It seems
>like a fuel supply issue. I didn't try turning on the electric boost pump
>(I have AFP fuel injection). I guess I'll try that tomorrow.
>
>I can't imagine how filling the tank could have any effect, so this is
>probably just a coincidence. Any suggestions?
>
>--
>Tom Sargent
Message 3
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Message 4
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| Subject: | Re: capacitive fuel probes (was: engine loping) |
At 07:26 AM 5/23/2010 Sunday, you wrote:
>All I have to do to be ready for my DAR inspection is to calibrate my capacitive
fuel probes.
<snip>
>--
>Tom Sargent
Hi Tom,
Which capacitive fuel probes do you have? I have the Princeton units that GRT
sells and haven't been able to even come close to getting them calibrated. Actually,
they went through the calibration fine (5 set points), but the readings
are completely erroneous. Sometimes they read full when the tanks are 1/2 empty.
Sometimes they read empty when the tanks are full. Sometimes they read,
well, whatever; usually not the actual amount of fuel. They are completely
useless. I've talked with Princeton, and they've offered no suggestions.
I'm not sure what to do at this point. Replacing the senders will likely require
removing the tanks which is no small job on the -7 and -8. Ack, this sucks.
I sure wish I'd just used the S&W float senders from Van's now.
Matt Dralle
RV-8 #82880 N998RV
http://www.mattsrv8.com - Matt's RV-8 Construction Log
http://www.youtube.com/MattsRV8 - Matt's RV-8 HDTV YouTube Channel
Status: Phase 1 Test Flying
Message 5
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| Subject: | Re: engine loping |
I would first make sure your vent isn't plugged?
-----Mark Rose 8A 137MR Original Message -----
From: thomas sargent
To: rv-list
Sent: Sunday, May 23, 2010 7:26 AM
Subject: RV-List: engine loping
All I have to do to be ready for my DAR inspection is to calibrate my
capacitive fuel probes. I taxied from the hangar to the fuel pumps (a
few hundred yards) on half a gallon of gas and then filled the left
tank. The engine ran OK on the way out. The plane has about an hour on
it taxiing and the engine has always run smoothly. On the way back from
the pumps with the left tank completely full, the engine wouldn't run at
a steady speed. It kept dropping RPM with a period of about 2 seconds.
If I tried to make it idle it would almost stop when the RPMs dropped.
I tried changing the mixture and running on one or the other ignition,
to no effect. It seems like a fuel supply issue. I didn't try turning
on the electric boost pump (I have AFP fuel injection). I guess I'll
try that tomorrow.
I can't imagine how filling the tank could have any effect, so this is
probably just a coincidence. Any suggestions?
--
Tom Sargent
Message 6
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| Subject: | Re: engine loping |
Lots of good questions. It did not run long at the fuel pump at all. I
stopped it 30 ft out and dragged it up to the pumps. Cyl. head temp was
about 300 F. Fueling (of just 1 tank) took half an hour or so because I was
calibrating both my fuel depth measuring tube and my capacitive fuel sensor.
I did not purge before restart, but I would assume after running 100 yards
or more, that wouldn't matter any more. Maybe not. It started easily. I
have no shroud on my fuel pump. I should also mention that this is just
about the first time I've really run the thing with the cowl on. I have a
cooling plenum, so the cooling air across the cylinders is about the same
with or without the cowl. However, the cooling of everything else - the
lines and the pump - would definitely change with the cowl in place. My
injectors are stock AFP - I haven't changed anything.
I plan to check the vent this afternoon. The wind is gusting so bad in
Tucson today, I may not want to drag it out of the hangar let alone trying
any taxi tests.
Message 7
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Filling the tank may have dislodged enough hidden building swarf to
partially clog the fuel supply system.
Be careful, check filters etc.
Jim in Kelowna
_____
From: owner-rv-list-server@matronics.com
[mailto:owner-rv-list-server@matronics.com] On Behalf Of thomas sargent
Sent: Sunday, May 23, 2010 7:27 AM
Subject: RV-List: engine loping
All I have to do to be ready for my DAR inspection is to calibrate my
capacitive fuel probes. I taxied from the hangar to the fuel pumps (a few
hundred yards) on half a gallon of gas and then filled the left tank. The
engine ran OK on the way out. The plane has about an hour on it taxiing and
the engine has always run smoothly. On the way back from the pumps with the
left tank completely full, the engine wouldn't run at a steady speed. It
kept dropping RPM with a period of about 2 seconds. If I tried to make it
idle it would almost stop when the RPMs dropped. I tried changing the
mixture and running on one or the other ignition, to no effect. It seems
like a fuel supply issue. I didn't try turning on the electric boost pump
(I have AFP fuel injection). I guess I'll try that tomorrow.
I can't imagine how filling the tank could have any effect, so this is
probably just a coincidence. Any suggestions?
--
Tom Sargent
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Message 8
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| Subject: | Re: capacitive fuel probes (was: engine loping) |
Matt:
I have the Princeton probes and I too regret not going with the low-tech
floats. The left tank is calibrated, I think. I have little experience
with it yet. The right tank gave me the "short" signal on the 3 LEDs when I
told it to calibrate empty. This afternoon I'm going to remove the drain
valve because as I recall the end of the probe is bearing right on it. I
can reach in with a screw driver or something and bend the probe up. If I
am lucky that will clear the short. If not, I'll have to remove the tank
and the probe. Todd at GRT told me that the outer tube can touch the tank,
but the inner conductor should not. I'll let you know how it goes. I wish I
had tested this stuff earlier.
On Sun, May 23, 2010 at 8:45 AM, Matt Dralle <dralle@matronics.com> wrote:
>
> At 07:26 AM 5/23/2010 Sunday, you wrote:
> >All I have to do to be ready for my DAR inspection is to calibrate my
> capacitive fuel probes.
> <snip>
> >--
> >Tom Sargent
>
>
> Hi Tom,
>
> Which capacitive fuel probes do you have? I have the Princeton units that
> GRT sells and haven't been able to even come close to getting them
> calibrated. Actually, they went through the calibration fine (5 set
> points), but the readings are completely erroneous. Sometimes they read
> full when the tanks are 1/2 empty. Sometimes they read empty when the tanks
> are full. Sometimes they read, well, whatever; usually not the actual
> amount of fuel. They are completely useless. I've talked with Princeton,
> and they've offered no suggestions.
>
>
--
Tom Sargent
Message 9
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| Subject: | Re: engine loping |
If the OAT was abofe 65F, you might have gotten a little vapor
lock....65 is my transition point. After you get a few hours on it, you
may want to go with the smaller nozzles - it keeps the pressure up and
lessens the chances of vapor lock.
I don't have a shroud on my pump either - but it is on the 'get soon'
list.
----- Original Message -----
From: thomas sargent
To: rv-list@matronics.com
Sent: Sunday, May 23, 2010 12:20 PM
Subject: Re: RV-List: engine loping
Lots of good questions. It did not run long at the fuel pump at all.
I stopped it 30 ft out and dragged it up to the pumps. Cyl. head temp
was about 300 F. Fueling (of just 1 tank) took half an hour or so
because I was calibrating both my fuel depth measuring tube and my
capacitive fuel sensor. I did not purge before restart, but I would
assume after running 100 yards or more, that wouldn't matter any more.
Maybe not. It started easily. I have no shroud on my fuel pump. I
should also mention that this is just about the first time I've really
run the thing with the cowl on. I have a cooling plenum, so the cooling
air across the cylinders is about the same with or without the cowl.
However, the cooling of everything else - the lines and the pump - would
definitely change with the cowl in place. My injectors are stock AFP -
I haven't changed anything.
I plan to check the vent this afternoon. The wind is gusting so bad
in Tucson today, I may not want to drag it out of the hangar let alone
trying any taxi tests.
Message 10
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This would be the first thing I'd look at as well.
If not yet done, you need to do a very through flush of the fuel system.
Attach a cheap in line fuel filter and some tubing to the firewall fuel line
and use your fuel pump to flush several gallons to a gas can. Shift tanks,
shake the plane, etc. If you use a clear fuel filter you can see when you
have clean gas flowing. This is also the time to do your fuel flow test
(get more fuel flow than your engine can use) - say 20+ GPH flow using your
electric fuel pump. Since you are running the gas through a filter it is ok
to put it back in the plane and flush some more.
As you already ran your engine, pull any engine associated finger type
filters and make sure you didn't fill them with trash.
Carl Froehlich
RV-8A (540 hrs)
RV-10 (systems install)
From: owner-rv-list-server@matronics.com
[mailto:owner-rv-list-server@matronics.com] On Behalf Of Jim Jewell
Sent: Sunday, May 23, 2010 12:27 PM
Subject: RE: RV-List: engine loping
Filling the tank may have dislodged enough hidden building swarf to
partially clog the fuel supply system.
Be careful, check filters etc.
Jim in Kelowna
_____
From: owner-rv-list-server@matronics.com
[mailto:owner-rv-list-server@matronics.com] On Behalf Of thomas sargent
Sent: Sunday, May 23, 2010 7:27 AM
Subject: RV-List: engine loping
All I have to do to be ready for my DAR inspection is to calibrate my
capacitive fuel probes. I taxied from the hangar to the fuel pumps (a few
hundred yards) on half a gallon of gas and then filled the left tank. The
engine ran OK on the way out. The plane has about an hour on it taxiing and
the engine has always run smoothly. On the way back from the pumps with the
left tank completely full, the engine wouldn't run at a steady speed. It
kept dropping RPM with a period of about 2 seconds. If I tried to make it
idle it would almost stop when the RPMs dropped. I tried changing the
mixture and running on one or the other ignition, to no effect. It seems
like a fuel supply issue. I didn't try turning on the electric boost pump
(I have AFP fuel injection). I guess I'll try that tomorrow.
I can't imagine how filling the tank could have any effect, so this is
probably just a coincidence. Any suggestions?
--
Tom Sargent
href="http://www.matronics.com/Navigator?RV-List">http://www.matronics.com/N
avigator?RV-List
href="http://forums.matronics.com">http://forums.matronics.com
href="http://www.matronics.com/contribution">http://www.matronics.com/contri
bution
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Message 11
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| Subject: | Re: engine loping |
I see that you are in AZ. So am I. While i wouldn't rule out the
possibility of some fuel line contamination. If you've got the strainers
and the Airflow Performance fuel filter installed, I don't think that's
the problem. It more likely that your engine got heat soaked during the
fueling. When this happens, the heat boils the fuel in the spider
distribution lines and results in an uneven / loping during ground ops.
If your didn't use the purge valve and run the pump for 30 secs its also
likely that this is the problem.This is particularly true and compounded
if you have a plenum because it traps the heat in a smaller area while
on the ground. We had 97 degrees here in PHX on Fri and that's plenty
warm enough to cause what you're experiencing. I'm guessing Tucson
wasn't far off. The boost pump / leaning won't help. I went through the
same thing, and after speaking with Don # Airflow Performance (he's very
familiar with this situation). I reduced the restrictors from .028
to.024, this causes higher pressure in the distribution lines which
eliminated the problem for me. It was disconcerting, but it only
happened during ground ops after a heat soaked engine.
Deems Davis
N519PJ
www.deemsrv10.com
On 5/23/2010 3:03 PM, Carl Froehlich wrote:
>
> This would be the first thing I'd look at as well.
>
> If not yet done, you need to do a very through flush of the fuel
> system. Attach a cheap in line fuel filter and some tubing to the
> firewall fuel line and use your fuel pump to flush several gallons to
> a gas can. Shift tanks, shake the plane, etc. If you use a clear
> fuel filter you can see when you have clean gas flowing. This is also
> the time to do your fuel flow test (get more fuel flow than your
> engine can use) -- say 20+ GPH flow using your electric fuel pump.
> Since you are running the gas through a filter it is ok to put it back
> in the plane and flush some more.
>
> As you already ran your engine, pull any engine associated finger type
> filters and make sure you didn't fill them with trash.
>
> Carl Froehlich
>
> RV-8A (540 hrs)
>
> RV-10 (systems install)
>
> *From:* owner-rv-list-server@matronics.com
> [mailto:owner-rv-list-server@matronics.com] *On Behalf Of *Jim Jewell
> *Sent:* Sunday, May 23, 2010 12:27 PM
> *To:* rv-list@matronics.com
> *Subject:* RE: RV-List: engine loping
>
> Filling the tank may have dislodged enough hidden building swarf to
> partially clog the fuel supply system.
>
> Be careful, check filters etc.
>
> Jim in Kelowna
>
> ------------------------------------------------------------------------
>
> *From:* owner-rv-list-server@matronics.com
> [mailto:owner-rv-list-server@matronics.com] *On Behalf Of *thomas sargent
> *Sent:* Sunday, May 23, 2010 7:27 AM
> *To:* rv-list
> *Subject:* RV-List: engine loping
>
> All I have to do to be ready for my DAR inspection is to calibrate my
> capacitive fuel probes. I taxied from the hangar to the fuel pumps (a
> few hundred yards) on half a gallon of gas and then filled the left
> tank. The engine ran OK on the way out. The plane has about an hour
> on it taxiing and the engine has always run smoothly. On the way back
> from the pumps with the left tank completely full, the engine wouldn't
> run at a steady speed. It kept dropping RPM with a period of about 2
> seconds. If I tried to make it idle it would almost stop when the
> RPMs dropped. I tried changing the mixture and running on one or the
> other ignition, to no effect. It seems like a fuel supply issue. I
> didn't try turning on the electric boost pump (I have AFP fuel
> injection). I guess I'll try that tomorrow.
>
> I can't imagine how filling the tank could have any effect, so this is
> probably just a coincidence. Any suggestions?
>
> --
> Tom Sargent
>
> * *
> * *
> *href="http://www.matronics.com/Navigator?RV-List">http://www.matronics.com/Navigator?RV-List*
> *href="http://forums.matronics.com">http://forums.matronics.com*
> *href="http://www.matronics.com/contribution">http://www.matronics.com/contribution*
> * *
>
>
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> http://www.matronics.================
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> - List Contribution Web generous nbsp; -->
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Message 12
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| Subject: | Re: engine loping |
Deems:
I'm leaning towards that explanation. I checked the vent lines today (by
connecting a tube to the inlets by the firewall and blowing into it) and
both vents are definitely clear. I should have stopped taxiing and tried
purging the line. I didn't do it again today because it was too windy out
there to risk it.
On Sun, May 23, 2010 at 3:55 PM, Deems Davis <deemsdavis@cox.net> wrote:
> I see that you are in AZ. So am I. While i wouldn't rule out the
> possibility of some fuel line contamination. If you've got the strainers and
> the Airflow Performance fuel filter installed, I don't think that's the
> problem. It more likely that your engine got heat soaked during the fueling.
> When this happens, the heat boils the fuel in the spider distribution lines
> and results in an uneven / loping during ground ops. If your didn't use the
> purge valve and run the pump for 30 secs its also likely that this is the
> problem.This is particularly true and compounded if you have a plenum
> because it traps the heat in a smaller area while on the ground. We had 97
> degrees here in PHX on Fri and that's plenty warm enough to cause what
> you're experiencing. I'm guessing Tucson wasn't far off. The boost pump /
> leaning won't help. I went through the same thing, and after speaking with
> Don # Airflow Performance (he's very familiar with this situation). I
> reduced the restrictors from .028 to.024, this causes higher pressure in the
> distribution lines which eliminated the problem for me. It was
> disconcerting, but it only happened during ground ops after a heat soaked
> engine.
>
> Deems Davis
> N519PJ
> www.deemsrv10.com
>
>
> Tom Sargent
Message 13
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| Subject: | Re: capacitive fuel probes (was: engine loping) |
Matt:
My half-baked idea seems to have worked. I unscrewed the right tank drain
valve, hooked a dental probe around the sensor tube and using a small screw
driver pushed up, bending it up 1/8 or 1/4". I could see that the central
conductor comes right to the end on that probe, so I guess it was in contact
with the bottom of the tank. After that I was able to get a successful
"empty" calibration point. It was too windy to taxi over to the pumps today
(gusts over 36mph) so I'll try calibrating it later this week. I can't say
yet if these probes will be flaky or not. I won't be surprised if there is
some further issues with them.
--
Tom Sargent
Message 14
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| Subject: | Re: engine loping |
Have you tried leaning the mixture with the mixture control while taxing? I
taxi with the mixture lean as posible. =0AB. Bell RV4 with IO320.- AFP f
uel system installed.- Do not archive.=0A=0Atowards that explanation.-
I checked the vent lines today (by connecting a tube to the inlets by the f
irewall and blowing into it) and both vents are definitely clear.- I shou
ld have stopped taxiing and tried purging the line.- I didn't do it again
today because it was too windy out there to risk it.=0A=0A=0AOn Sun, May 2
3, 2010 at 3:55 PM, Deems Davis <deemsdavis@cox.net> wrote:=0A=0AI see that
you are in AZ. So am I. While i wouldn't rule out the possibility of some
fuel line contamination. If you've got the strainers and the Airflow Perfor
mance fuel filter installed, I don't think that's the problem. It more like
ly that your engine got heat soaked during the fueling. When this happens,
the heat boils the fuel in the spider distribution lines and results in an
uneven / loping during ground ops. If your didn't use the purge valve and r
un the pump for 30 secs its also likely that this is the problem.This is pa
rticularly true and compounded if you have a plenum because it traps the he
at in a smaller area while on the ground. We had 97 degrees here in PHX on
Fri and that's plenty warm enough to cause what you're experiencing. I'm gu
essing Tucson wasn't far off. The boost pump / leaning won't help. I went t
hrough the same thing, and after speaking with Don # Airflow Performance (h
e's very familiar with this situation).- I reduced the
restrictors from .028 to.024, this causes higher pressure in the distribut
ion lines which eliminated the problem for me. It was disconcerting, but it
only happened during ground ops after a heat soaked engine.- =0A>=0A>Dee
ms Davis=0A>N519PJ=0A>www.deemsrv10.com =0A>=0A>=0A>Tom Sargent=0A=0A=0A=0A
============
Message 15
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| Subject: | Re: capacitive fuel probes (was: engine loping) |
Hi Tom,
I'm really interested in your accuracy reports. Please post when you have some
data. So far, mine are completely worthless. I'm thinking of recalibrating,
but the first time I did the procedure went perfectly on both sides so I'm thinking
that won't change anything.
Were your prebend by Princeton for the RV tanks? Kind of a "U" shape?
Matt
At 04:14 PM 5/23/2010 Sunday, you wrote:
>Matt:
>My half-baked idea seems to have worked. I unscrewed the right tank drain valve,
hooked a dental probe around the sensor tube and using a small screw driver
pushed up, bending it up 1/8 or 1/4". I could see that the central conductor
comes right to the end on that probe, so I guess it was in contact with the
bottom of the tank. After that I was able to get a successful "empty" calibration
point. It was too windy to taxi over to the pumps today (gusts over 36mph)
so I'll try calibrating it later this week. I can't say yet if these probes
will be flaky or not. I won't be surprised if there is some further issues with
them.
>
>--
>Tom Sargent
Matt Dralle
RV-8 #82880 N998RV
http://www.mattsrv8.com - Matt's RV-8 Construction Log
http://www.youtube.com/MattsRV8 - Matt's RV-8 HDTV YouTube Channel
Status: Phase 1 Test Flying
Message 16
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| Subject: | Re: capacitive fuel probes (was: engine loping) |
Matt:
The best advice I can give anyone contemplating capacitive fuel sending
units is: "Don't do it - stick with the resistive, float units." I bought
my capacitive sending units from Vans along with the wing kit, and the
Princeton converters from GRT. It's a useless combination. I've lost trac
k
of how many times I've drained my fuel tanks and recalibrated the
converters. (What was it Einstein said?
"Insanity is doing the same thing, over and over again, expecting different
results.") Right now they tell me the left tank is empty when it has 12 -
14 gallons in it; the right tank is a bit more accurate but not much. I've
spent time on the phone with Sandy and Todd at GRT; they try to be helpful
but nothing has worked. The only alternative seems to be to pull the tanks
and install float units; and I have no illusions as to what's involved, a
real pain in the butt. Thank God the totalizer is spot on accurate.
Dan
RV-7A - N307TB
145 hours since first flight on Aug 4, 2009
On Sun, May 23, 2010 at 8:13 PM, Matt Dralle <dralle@matronics.com> wrote:
>
> Hi Tom,
>
> I'm really interested in your accuracy reports. Please post when you hav
e
> some data. So far, mine are completely worthless. I'm thinking of
> recalibrating, but the first time I did the procedure went perfectly on b
oth
> sides so I'm thinking that won't change anything.
>
> Were your prebend by Princeton for the RV tanks? Kind of a "U" shape?
>
> Matt
>
> At 04:14 PM 5/23/2010 Sunday, you wrote:
> >Matt:
> >My half-baked idea seems to have worked.=C2 I unscrewed the right tank
> drain valve, hooked a dental probe around the sensor tube and using a sma
ll
> screw driver pushed up, bending it up 1/8 or 1/4".=C2 I could see that t
he
> central conductor comes right to the end on that probe, so I guess it was
in
> contact with the bottom of the tank.=C2 After that I was able to get a
> successful "empty" calibration point.=C2 It was too windy to taxi over t
o the
> pumps today (gusts over 36mph) so I'll try calibrating it later this week
. I
> can't say yet if these probes will be flaky or not.=C2 I won't be surpri
sed
> if there is some further issues with them.
> >
> >--
> >Tom Sargent
>
> Matt Dralle
> RV-8 #82880 N998RV
> http://www.mattsrv8.com - Matt's RV-8 Construction Log
> http://www.youtube.com/MattsRV8 - Matt's RV-8 HDTV YouTube Channel
> Status: Phase 1 Test Flying
>
>
===========
===========
===========
===========
>
>
Message 17
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| Subject: | Re: capacitive fuel probes (was: engine loping) |
Matt:
Mine were pre-bent for the 6A. Maybe that makes a difference, I don't
know. Your experience and Dan's leaves me expecting lots of problems.
I'll keep the list appraised of my results.
Hi Tom,
>>
>> I'm really interested in your accuracy reports. Please post when you have
>> some data. So far, mine are completely worthless. I'm thinking of
>> recalibrating, but the first time I did the procedure went perfectly on both
>> sides so I'm thinking that won't change anything.
>>
>> Were your prebend by Princeton for the RV tanks? Kind of a "U" shape?
>>
>> Matt
>>
>>
--
Tom Sargent
Message 18
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| Subject: | Re: engine loping |
You might want to recheck the tightness of the fuel line connecters.
We had a similar case today with a first start on an io 360 ---
turned out a lose fitting was allowing a little air into the system --
tightened the fitting and the engine ran smooth--no loping.
good luck
dave
On May 23, 2010, at 3:55 PM, Deems Davis wrote:
> I see that you are in AZ. So am I. While i wouldn't rule out the
> possibility of some fuel line contamination. If you've got the
> strainers and the Airflow Performance fuel filter installed, I don't
> think that's the problem. It more likely that your engine got heat
> soaked during the fueling. When this happens, the heat boils the
> fuel in the spider distribution lines and results in an uneven /
> loping during ground ops. If your didn't use the purge valve and run
> the pump for 30 secs its also likely that this is the problem.This
> is particularly true and compounded if you have a plenum because it
> traps the heat in a smaller area while on the ground. We had 97
> degrees here in PHX on Fri and that's plenty warm enough to cause
> what you're experiencing. I'm guessing Tucson wasn't far off. The
> boost pump / leaning won't help. I went through the same thing, and
> after speaking with Don # Airflow Performance (he's very familiar
> with this situation). I reduced the restrictors from .028 to.024,
> this causes higher pressure in the distribution lines which
> eliminated the problem for me. It was disconcerting, but it only
> happened during ground ops after a heat soaked engine.
>
> Deems Davis
> N519PJ
> www.deemsrv10.com
>
> On 5/23/2010 3:03 PM, Carl Froehlich wrote:
>>
>> This would be the first thing I=92d look at as well.
>>
>> If not yet done, you need to do a very through flush of the fuel
>> system. Attach a cheap in line fuel filter and some tubing to the
>> firewall fuel line and use your fuel pump to flush several gallons
>> to a gas can. Shift tanks, shake the plane, etc. If you use a
>> clear fuel filter you can see when you have clean gas flowing.
>> This is also the time to do your fuel flow test (get more fuel flow
>> than your engine can use) ' say 20+ GPH flow using your electric
>> fuel pump. Since you are running the gas through a filter it is ok
>> to put it back in the plane and flush some more.
>>
>> As you already ran your engine, pull any engine associated finger
>> type filters and make sure you didn=92t fill them with trash.
>>
>> Carl Froehlich
>> RV-8A (540 hrs)
>> RV-10 (systems install)
>>
>> From: owner-rv-list-server@matronics.com
[mailto:owner-rv-list-server@matronics.com
>> ] On Behalf Of Jim Jewell
>> Sent: Sunday, May 23, 2010 12:27 PM
>> To: rv-list@matronics.com
>> Subject: RE: RV-List: engine loping
>>
>> Filling the tank may have dislodged enough hidden building swarf to
>> partially clog the fuel supply system.
>> Be careful, check filters etc.
>>
>> Jim in Kelowna
>>
>> From: owner-rv-list-server@matronics.com
[mailto:owner-rv-list-server@matronics.com
>> ] On Behalf Of thomas sargent
>> Sent: Sunday, May 23, 2010 7:27 AM
>> To: rv-list
>> Subject: RV-List: engine loping
>>
>> All I have to do to be ready for my DAR inspection is to calibrate
>> my capacitive fuel probes. I taxied from the hangar to the fuel
>> pumps (a few hundred yards) on half a gallon of gas and then filled
>> the left tank. The engine ran OK on the way out. The plane has
>> about an hour on it taxiing and the engine has always run
>> smoothly. On the way back from the pumps with the left tank
>> completely full, the engine wouldn't run at a steady speed. It
>> kept dropping RPM with a period of about 2 seconds. If I tried to
>> make it idle it would almost stop when the RPMs dropped. I tried
>> changing the mixture and running on one or the other ignition, to
>> no effect. It seems like a fuel supply issue. I didn't try
>> turning on the electric boost pump (I have AFP fuel injection). I
>> guess I'll try that tomorrow.
>>
>> I can't imagine how filling the tank could have any effect, so this
>> is probably just a coincidence. Any suggestions?
>>
>> --
>> Tom Sargent
>>
>>
>>
href="http://www.matronics.com/Navigator?RV-List">http://www.matronics.c
om/Navigator?RV-List
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Message 19
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| Subject: | Re: engine loping |
Yes, I tried leaning it while taxiing. It had no effect. The engine isn't
broken in yet and Aerosport says to run full rich, so that's what I've been
doing. I suspect the problem was that I needed to use the purge valve+
boost pump to flush cold fuel thru the system. An air leak is a good
possibility too. I have pretty much ruled out plugged vent lines.
On Sun, May 23, 2010 at 4:30 PM, Bruce Bell <brucebell74@sbcglobal.net>wrote:
> Have you tried leaning the mixture with the mixture control while taxing? I
> taxi with the mixture lean as posible.
> B. Bell RV4 with IO320. AFP fuel system installed. Do not archive.
>
>
> --
Tom Sargent
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