Vortech, 440cc Injectors, Walbro, Returnless Fuel System w/ FMU 6/1

Fuel Pressure Gauge Behavior Normal with above setup.

1. Key On/ Engine/Off, pump runs for 1-2 seconds and shuts off. Reading 54 PSI steady every time on the money with above setup

2. Engine/ON, No change, (Normal)


New Setup, Added 600cc Injector, change FMU from 6/1 to 3/1

Fuel Pressure Gauge Behavior with this change

1. Key On/ Engine/Off, pump runs for 1-2 seconds and Shuts Off. Reading first 1-2 seconds while pump is running, 54 PSI, when Pump shuts off, gauge instantly drops to 48PSI, and then continues to drop at a rate of 2PSI every 60 Seconds.

Also I should Note that the Pump is not always shutting off w/ key on/engine/off, it's about 50/50 now. It did that just a hand full of time in 3 years with the 440cc.

2. Engine/ON, Steddy 54PSI

OK, first thing I think of is a Fuel Leak, Right.....

I have no signs of a Leak other than pressure drop.

No Fuel Smell.

Could this all be going on in the Tank? And if so, why this change when I added larger injectors?

Please Experience Fuel System People Only......Thanks.....

Thanks Again,

TimRod

 

Anybody.......

 

my pressure drop just like that, but I have a RFS. You are using a non-return setup, correct? The only way it could be doing that is against the pump.

Why it started when you changed injectors might just be coincidence.

 

it's a non return setup.....

what do mean against the pump?

 

the check valve in the pump is leaking

 

any update?

as long as the FP is holding steady/rising when you are driving, I wouldnt worry about it.

 

today I pulled off the fuel line before the rails and installed a pressure gauge. I did exactly the same thing. Verified, check valve trickle down, no worrys......

All is good, thanks for the help......