---------------------------------------------------------- Engines-List Digest Archive --- Total Messages Posted Sat 08/04/12: 3 ---------------------------------------------------------- Today's Message Index: ---------------------- 1. 05:47 AM - Re: Help me solve engine power loss (Steve Thomas) 2. 10:24 AM - Re: Help me solve engine power loss (FLYaDIVE) 3. 09:20 PM - Re: Engine power loss (DEAN PSIROPOULOS) ________________________________ Message 1 _____________________________________ Time: 05:47:17 AM PST US Subject: Re: Engines-List: Help me solve engine power loss From: Steve Thomas Have you checked the integrity of your engine electrical ground? Steve Thomas ________________________________________________________________________ On Aug 3, 2012, at 6:55 PM, Speedy11@aol.com wrote: > > Engine gurus, > I have a problem with my engine that has me stumped. Maybe someone has seen this situation before or has an idea for resolution. > I have a Barrett IO-390 (essentially same as IO-360) that began missing and losing power in June. I tracked down several "problems" which the solution to I thought would solve the power loss. I found one spark plug that seemed to be a problem. Replaced all plugs and tested them before installation. Problem still there. Checked resistance in harness. All good. Replaced harness anyway. Problem still there. Sent P Mags back to factory for overhaul. Essentially have new P Mags now. Problem still there. Cleaned injectors and flow tested. Flows all equal. Cleaned fuel filter - nothing there. There is no air filter when I run ram air, so nothing to inhibit air flow. I checked the sniffle valve but no leak there. > On takeoff roll there seems to be slightly less power, but the power loss is more noticeable (approx 20% loss) once airborne. At pattern altitude with reduced power the engine runs ok. But as I add throttle (high RPM on prop) the engine loses power as if it is loading up. The EGTs and CHTs are normal. The RPM and MP are normal. > So, there you go. Any ideas? > Stan Sutterfield > RV-8A. Port Orange, FL > > > > > > > ________________________________ Message 2 _____________________________________ Time: 10:24:10 AM PST US Subject: Re: Engines-List: Help me solve engine power loss From: FLYaDIVE Stan: Some ideas I had: - How did you clean the injectors? A standard way is to soak them in Hoppies #9 Gun Solvent. The flow could be all equal - But they could be all slightly restricted. - Does the fuel lines from the spider contact any part of the engine? HEAT could be causing a vapor bubble. - Since you have a CS prop, do you think or feel the loading ONLY when increasing the RPM? This could be a SLOW reacting Governor and that would cause loading. - Can you monitor your ALL your EGT 's at the same time and see if a cylinder drops in temperature at the same time loss of power occurs? - The spark plug that was a problem: Was it indicating Oil or Carbon? Keep an eye on that plug and see if the problem begins again. It could indicate a sticky Exhaust Valve. So, replacing the plug will not fix the valve. - Have you done the Valve Wobble test (SB-388)? - OK, with this one I am reaching a bit: I have read about someone that "Improved" the intake air flow to the engine. And in doing so, the forced air was so great that it disturbed the airflow through the Carb. - I know you do not have a Carb, but how does it fly without the Ram Air? - Have you inspected the ducting - I'm guessing SCAT Tube. Could that have an obstruction or could it be collapsing? That's all for now... Barry ====================== On Fri, Aug 3, 2012 at 9:55 PM, wrote: > > Engine gurus, > I have a problem with my engine that has me stumped. Maybe someone has > seen this situation before or has an idea for resolution. > I have a Barrett IO-390 (essentially same as IO-360) that began missing > and losing power in June. I tracked down several "problems" which the > solution to I thought would solve the power loss. I found one spark plug > that seemed to be a problem. Replaced all plugs and tested them before > installation. Problem still there. Checked resistance in harness. All > good. Replaced harness anyway. Problem still there. Sent P Mags back to > factory for overhaul. Essentially have new P Mags now. Problem still > there. Cleaned injectors and flow tested. Flows all equal. Cleaned fuel > filter - nothing there. There is no air filter when I run ram air, so > nothing to inhibit air flow. I checked the sniffle valve but no leak there. > On takeoff roll there seems to be slightly less power, but the power loss > is more noticeable (approx 20% loss) once airborne. At pattern altitude > with reduced power the engine runs ok. But as I add throttle (high RPM on > prop) the engine loses power as if it is loading up. The EGTs and CHTs are > normal. The RPM and MP are normal. > So, there you go. Any ideas? > Stan Sutterfield > RV-8A. Port Orange, FL > > ________________________________ Message 3 _____________________________________ Time: 09:20:35 PM PST US From: "DEAN PSIROPOULOS" Subject: Engines-List: RE: Engine power loss I had a problem with a bad idle on my AFP injected parallel valve 0-360 Stan. After 5 months of trouble shooting I discovered that the flow divider (on top of the engine) was sticking. How I figured that out was to tee in a mechanical pressure gauge between the servo and the flow divider (not at fuel pump outlet, you won't get accurate readings there). You'll need one calibrated with a 0-10 PSI range. I ran a hose up to the canopy from the tee and connected it to the gauge there so I could see the reading from the cockpit. Then I started the engine and watched the gauge while I was advancing the throttle. The engine stumbled and the pressure reading went a couple PSI above where it should have been before dropping back and acting normally (ie. going up and down with throttle movement). After consulting with Don Rivera at AFP the conclusion was a sticky flow divider so I returned it to him for repair. The engine ran like a top after it was fixed. Another friend with a Bendix system found a small piece of black tape plugging up one of the fuel ports in his flow divider but that was during first run when one EGT showed a cold cylinder (so much for the integrity of FI rebuilders). After that was fixed it still ran a bit rough and when he did the flow matching test (with the 4 cups under the injectors) he found one somewhat constricted. So he soaked that injector in Hoppes gun cleaner and viola, engine runs great. Troubleshooting the fuel system can be very frustrating. By the time I finally figured out the flow divider problem I was so disgusted that I had started to look for a Marvel carb. And I'm a pretty patient guy. Dean Psiropoulos RV-6A N197DM FL to Indy 2012 without a hiccup __________________________ Original Message _____________________________ Subject: Engines-List: Help me solve engine power loss From: speedy11@aol.com Engine gurus, ... On takeoff roll there seems to be slightly less power, but the power loss is more noticeable (approx 20% loss) once airborne. At pattern altitude with reduced power the engine runs ok. But as I add throttle (high RPM on prop) the engine loses power as if it is loading up. The EGTs and CHTs are normal. The RPM and MP are normal. Stan Sutterfield ------------------------------------------------------------------------------------- Other Matronics Email List Services ------------------------------------------------------------------------------------- Post A New Message engines-list@matronics.com UN/SUBSCRIBE http://www.matronics.com/subscription List FAQ http://www.matronics.com/FAQ/Engines-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/engines-list Browse Digests http://www.matronics.com/digest/engines-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.