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Fuel Pressure Issue

Posted: Fri Dec 13, 2019 4:33 pm
by digginfool
I have diagnostic software that allows me to monitor virtually any aspect of engine performance. I'm running an Aeromotive Eliminator fuel pump with an Aeromotive Bypass Regulator. When I originally installed the engine, and up to about 100 hours ago, I had 63 psi fuel pressure that would drop to about 60 psi at WOT. Last weekend, I did a test run and recorded the results so I could review. All other aspects of the engine's performance was as it always has been but I noticed that now at idle, I had 57 psi that would drop to around 51 psi at WOT. Thinking I had dirty fuel filters, I changed the water separator, cleaned the 100 micron input filter and the 10 micron output filter (which ended up being nearly clogged shut) but the fuel pressure has not changed. My question is, then, should I recalibrate the regulator? Do they change over time or is it possible I damaged the pump with the dirty 10 micron filter? I was surprised that the 10 micron filter was so dirty as the water separator is also 10 micron. The engine is not experiencing any knock (at least not that the sensors can pick up) but with pressure dropping into the low 50s, it's just a matter of time before things start getting lean.

Re: Fuel Pressure Issue

Posted: Fri Dec 13, 2019 5:07 pm
by hogdoggin
Something to check I run a aeromotive boost reference regulator and I've had to replace the diaphragm twice now in a year. Gets a pin hole in it and starts leaking fuel out the vacuum port.

Re: Fuel Pressure Issue

Posted: Fri Dec 13, 2019 6:17 pm
by SWAMPHUNTER45
I have observed on my low pressure systems that ambient temperature will effect pressure.

Re: Fuel Pressure Issue

Posted: Sat Dec 14, 2019 10:00 am
by digginfool
hogdoggin wrote:
Fri Dec 13, 2019 5:07 pm
Something to check I run a aeromotive boost reference regulator and I've had to replace the diaphragm twice now in a year. Gets a pin hole in it and starts leaking fuel out the vacuum port.
I'll have to check that. My regulator does have the boost reference port but I do not have it hooked up (I was instructed not to). Thanks!

Re: Fuel Pressure Issue

Posted: Sun Dec 15, 2019 8:17 am
by Rich Andrews
What kind of fuel line specific brand are you running