Hello Steve and Brandon,
I wanted to pick back up on this issue as it relates to the idle issue Brandon was experiencing.
Back in Nov of 2020 I reported everything was working great after the mech pump, fuel injector, etc was rebuilt. There was a problem with the mechanical pump. Around May or June I started noticing a problem similar to what Brandon described, with electric pump ON idle is perfect, With the electric pump OFF the engine does not what to idle below about 800 RPM. I/we have done some testing of fuel pressures and flow (on the JPI) with the electric pump on and off. I could type a lot of info but a few items stand out.
1- The fuel pressure with the electric pump ON and the engine OFF is 38PSI.
At idle aprox 650RPM-
2- With the engine running and the electric pump OFF the mech pump pressure is 37 PSI.
3- Electric pump on (both pumps) about 43 PSI
This is where it seems odd:
4- Fuel flow on the JPI with electric pump on reads 1.8gph (engine idles great)
5- FF with electric pump off reads 3.0gph? (idle problem)
6- Idle mixture is set by the book (electric pump on) for a 50RPM peak when leaning mixture, I do not get this peak with the electric pump off but the manual states the electric pump MUST BE ON to set idle speed and mixture.
So I am a bit curious if others experience idle issues wit the electric pump off? It sounds like Brandon fixed his issue? Also can anyone provide me with the fuel flow data with electric pump on and off if you have an engine monitor setup?
Part of what puzzles me about this is it worked great for 6 months (colder weather), also when reading in detail the POH states the electric pump should always be ON for all ground operations, etc except when testing the mech pump? My checklist was written different and I have for 10 years turned the electric pump off after starting the engine and turned it back on prior to TO, never had an idle problem.
Open to any thoughts.
Joe
