avex

Is fuel pressure supposed to immediately drop to 0 when you turn off your car? I thought pressure is retained until it gradually drops back to 0 in about an hour or two. Also when I put my key to the on position The fuel pressure builds up, but starts dropping down immediately, like it won't hold pressure.

quik1

No its not supposed to drop right away . Look for obvious leaks near the injectors fuel filter and other connections. You could have a leaky injector.

poison

Depends on what fuel pressure you run on your motor. It is normal for it to go to 0 when you turn off the car and running something like an adjustable FPR.

My car goes to 0 on the fuel gauge but that is because I am running 38 PSI at idle, so when you turn off your car, all the fuel goes back to the tank.

HONDADNA

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by poison &raquo;</TD></TR><TR><TD CLASS="quote">Depends on what fuel pressure you run on your motor. It is normal for it to go to 0 when you turn off the car and running something like an adjustable FPR.

My car goes to 0 on the fuel gauge but that is because I am running 38 PSI at idle, so when you turn off your car, all the fuel goes back to the tank.</TD></TR></TABLE>

fuel pressure is not suppose to drop when key is turned off even if you have a FPR.

Calavera

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by quik1 &raquo;</TD></TR><TR><TD CLASS="quote">No its not supposed to drop right away . Look for obvious leaks near the injectors fuel filter and other connections. You could have a leaky injector.</TD></TR></TABLE>

besides clogged injectors, fuel filter, fpr, what else could cause pressure to drop? I do not see any fuel leaking visually. I have a fp leak problem.

T4eg

fuel pressure is not susposed to drop when you turn the key off. The fuel system says primed (normal pressure) until you start it up again. (Electronic Fuel Injection)

avex

what could cause the pressure to drop then?

StyleTEG

Any sort of leak will lead to inability to keep pressure in the system.

Do you always close your gas cap with at least three clicks?

T4eg

Leaky injectors or injector seals that go into the fuel rail.

EE_Chris

There exists a check valve in the fuel pump itself that holds pressure when the engine is not running.

I'm unsure of aftermarket pumps and their associated check valves, but are you running an aftermarket pump?

scottcrxsi

Not to worry. There is a check valve in the Fuel pump sending unit. It's quite common for those to start leaking, allowing your fuel to leak back into the tank. The only draw back you should notice is it'll take a few second to start the engine (pump has to pressuize the line.)
For everyones info, the fuel pressure should remain after the engine is stopped. The OEM's don't want there new cars to take a second or two to start.

PHiZ

Do you have an electrical fuel pressure gauge?

-PHiZ

poison

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by EE_Chris &raquo;</TD></TR><TR><TD CLASS="quote">There exists a check valve in the fuel pump itself that holds pressure when the engine is not running.

I'm unsure of aftermarket pumps and their associated check valves, but are you running an aftermarket pump?</TD></TR></TABLE>

This would most likely be the cause. My car runs perfectly fine, and when I turn off my car, fuel pressure goes to 0.

I forgot to mention I have a Walbro 255 as well.

99_SH

If you have an electrical gauge, its going to read 0 when you turn the car off, because the gauge is not getting any voltage! You've shut the power off,

jerseybrandon

Sounds like a FPR problem, use a vacuum pump to test your FPR, if you have an aftermarket one, I'm sure the manufacurer has test procedures. Where is your Fuel pressure guage tapped to anyway?

avex

I have a mechanical gauge lol, it's tapped into the fpr itself.

poison

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by avex &raquo;</TD></TR><TR><TD CLASS="quote">I have a mechanical gauge lol, it's tapped into the fpr itself.</TD></TR></TABLE>

Your gauge should be tapped into the fuel filter.

ECKOTYPER

NOPE PRESSURE STAYS IN THERE MOSTLY ALL THE TIME! GAS STARTS GOING TO THE MOTOR B4 U EVEN TURB IT FULLY OVER

Joon525

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by poison &raquo;</TD></TR><TR><TD CLASS="quote">Depends on what fuel pressure you run on your motor. It is normal for it to go to 0 when you turn off the car...</TD></TR></TABLE>
This is what happens to my car. If I let it sit overnight the fuel pressure gauge (mechanical and mounted on the fuel rail itself) will end up at 0. I always thought this this normal though.


Modified by Joon525 at 10:01 AM 9/17/2003

carolinaACCORD

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by poison &raquo;</TD></TR><TR><TD CLASS="quote">

Your gauge should be tapped into the fuel filter.</TD></TR></TABLE>

Actually, the closer to the injectors you can get the gauge is best. So it will read the REAL pressure at the injectors (where it matters).