it started last year, when i noticed that everytime i shut down the engine it was hard to start. so me and a bud pinpointed the problem on the aem fpr, which wasn't holding any pressure at all.

problems continued even after i bought a aem fpr rebuild kit.

so i bought an used b&m fpr until i had money for another aem.

recently i got one from a friend of mine, which was sold to me in pristine condition.

i installed it, and guess what: same symptoms. shut down the engine, immediate loss of base fuel pressure, which in turn makes the engine hard to start for about 10 seconds, more or less.

so i put back the b&m and it works wonders.

i googled "aem doesn't hold pressure" ans found out that there are other guys in the same situation as mine.

what could have happened?

does any of you experiment the same situation as mine?

can i use the aem without any risk, even when its not holding pressure?

There really are very few reasons to run an aftermarket FPR, stock ones work all kinds of good in most applications. Unless you're doing a crazy boost build, I dont see the need for one.

As far as the AEM losing pressure, I dont suppose it smells like fuel... ever does it?

there's no fuel smell...

Okay so your saying the b&m fpr worked without the same symptoms? Or does it still do?

the b&m works fine. no instant pressure drop issues like the aem ones.

with the aem the fuel gauge slams to cero once i shut off the engine.

with the b&m it takes the fuel gauge an hour and a half to get back to cero.

Uh, are you talking about the fuel level gauge in your gauge cluster or the fuel pressure gauge?

If the fuel pressure gauge is dropping, then try replacing it with a new one or a known good one.

If the fuel level gauge (in your cluster) is dropping to empty once the car is off, try checking the grounds at the tank and also try replacing the sending unit.

yes, i was referring to the fuel gauge i installed at the fuel rail. sorry for not pinpointing that.

well so far i have a b&m fpr and it's working a-ok.

but i've heard stories about b&ms failing at accurately working with the lbs. you set it at.

Wait, doesnt the B&M replace like half the stock pressure regulator but the AEM is a complete all in one unit?

yes. the aem is a full unit, the b&m you need the lower part of your oem fpr.

I agree what he said about replacing the gauge. I've seen some that went bad. And for B&M yes they do fail.

hm. i think there's a misunderstanding and it has to be my fault.

my problem isn't with the b&m fuel pressure regulator. it is with both aem fprs i have.

they seem to work fine, but doesn't hold any pressure once i shut down the engine. that indicates me that maybe that both fprs are bad.

the b&m fpr i have now is working fine: it still holds pressure after i shut down the engine. the fuel pressure gauge is a new one and filled with liquid.

logic tells me that if the b&m holds fuel pressure while the aems aren't, well last two are bad. it is quite difficult for me to pinpoint the fuel pump as the clprit since the symptom occurs with the aem fprs.

my concern with the b&m fpr is that i heard lot of bad stuff about them, especially that they aren't accurate.

my question was and still is if any of you had the same problems i have with the aem fprs.

Maybe that's what AEM's are designed to do? Bleed the pressure off for whatever reason.

update: switched to a holley fpr, and problem has ended.

holley's construction and attention to detail is superior than aem by far