SMOKINV8

iTrader: (6)

I've been having a pretty strange (minor) fuel pressure issue for quite some time now, but I haven't been able to figure out what is causing it. Here's the symptoms.

At start-up, fuel pressure is fine. It stays rock solid at the 62psi I have it set at. After I cruise around for a while (doesn't matter if I have a heavy foot or not), the fuel pressure starts to gradually bleed off while cruising at a constant speed. If I stab the throttle a little, it's like the fuel pressure sort of "wakes up," and jumps back up to the 62psi. However, it then bleeds back down as I cruise along at a constant speed again.

I e-mailed Aeromotive about it, and they recommended I remove the vacuum port and put teflon tape on it, and only thread half the threads in place, as the threads could be going deep enough to interfere with the pressure spring. I did that, but it didn't solve the problem.

Has anyone encountered anything like this before? I'd like some better proof before I drop the cash on a replacement regulator.

89lx-ls1

iTrader: (23)

sURE ITS NOT SOMETHING LIKE THE PUMP

SMOKINV8

iTrader: (6)

Not 100% sure, but pretty sure, yes.

If it was the pump, it wouldn't recover as it does. It also holds the pressure fine under heavy loads, ie it isn't a weak pump not being able to keep up with everything.

I have a racetronix in tank setup, so I would hope it could keep up with a H/C setup at least. I know I'm not making 600hp+.

SMOKINV8

iTrader: (6)

Okay, if nobody has had this problem, would it be feasible that heat is causing heat expansion, which is causing some kind of binding with the pressure regulator spring?

Racetronix

iTrader: (2)

Are you using an electrical fuel pressure gauge?

SMOKINV8

iTrader: (6)

Yes I am, its an Autometer full sweep gauge. Are you thinking there might be something up with the pressure diaphram in the FP gauge sending unit?

Racetronix

iTrader: (2)

We have seen some pressure sensors drop upwards of 10PSI in their output when they get heatsoaked on top of the motor.

V6 Bird

iTrader: (15)

Im going to say that ive had sending units be the problem here for you...Put a mechanical guage on the car and verify this for yourself. It wouldnt be the first time this was the problem....Im going to say is that before its problems with anything else.

SMOKINV8

iTrader: (6)

Interesting idea... I may try fabricating a little heat shield to put in place to see if it makes a difference or not. Thanks for the info guys.