Poll: Fuel Pressure drop when turning off motor - SRT Forums

Gmanigio · 07-18-2008, 11:51 PM

Im one of many with fuel pressur problems and wanna get it squared away. Just curious how many are out there with the same problem.

Also, if you fixed your problem, what did you do??

I tried the "pushing the FPR in" but it did nothing for me.

I ordered a PTP O-ring 3 weeks ago but he gave me a refund for me complaining that I never got it 2+ weeks later.

Just want some input on whatelsle to check. I tightened down ALL connection on my Returnline. I built it myself, Could I have not installed the SS line into the fitting all the way???

bpsrt4 · 07-18-2008, 11:52 PM

Quote: Originally Posted by Gmanigio

I built it myself, Could I have not installed the SS line into the fitting all the way???

I think it would be leaking if that was the case

But, I have no idea about what my fuel pressure did after i shut the car off when I had an AGP returnline, I have converted the AGP to be after the rail (just waiting on a fuel rail) So I guess I'll have to get back to this thread

Gmanigio · 07-18-2008, 11:55 PM

Quote: Originally Posted by bpsrt4

I think it would be leaking if that was the case

I built it last summer, and pushed the SS line ALL the way in as far as possible.

The stock FPR moves around some, so that may be the culprit. Just wondering what others have done.

Turbocruiser13 · 07-19-2008, 01:55 AM

I never had a problem with mine at first (built it myself) it would take roughly 1 1/2-2 hours for it to drop completely to zero. Then all of a sudden out of the blue it's now dropping down instantly. I had a leak in my fuel line (the return side was rubbing against the trans and wore a hole in my SS braided line) and I eventually got that fixed but it still drops instantly. Doesn't really bother me a whole lot since I have a push button starter on the car. By the time I turn the ignition on then reach down and push the button the car is already primed so I don't have to sit there and crank it like crazy.

Gmanigio · 07-19-2008, 10:35 AM

Quote: Originally Posted by Turbocruiser13

I never had a problem with mine at first (built it myself) it would take roughly 1 1/2-2 hours for it to drop completely to zero. Then all of a sudden out of the blue it's now dropping down instantly. I had a leak in my fuel line (the return side was rubbing against the trans and wore a hole in my SS braided line) and I eventually got that fixed but it still drops instantly. Doesn't really bother me a whole lot since I have a push button starter on the car. By the time I turn the ignition on then reach down and push the button the car is already primed so I don't have to sit there and crank it like crazy.

BUt will that affect overall performance??

I was at he dyno, at 48psi then seeing 23psi of boost. That should be 71psi on the FPR gauge. But the most I saw at WOT full boost was 60-62psi, and I thought it was because of a leak, and the leak was part of dropping to 0 part.

My line is also sitting on the transmission, I should check it again, but last I checked it was ok. I should buy a 90* fitting for that

Turbocruiser13 · 07-19-2008, 03:11 PM

I have no 1:1 hooked up because it was too hard to tune for me. Felt like I was gonna wash out the cylinders or pull 20 degrees of timing trying to get the fuel down lol. With my 57 trim and 650 injectors my pressure is only 47-50psi boosting 21psi and ending up with an 11.5-11.8afr so I really can't complain with how the car's running and there were no performance issues at all once the fuel started dropping when the car was shut off.

bpsrt4 · 07-19-2008, 06:29 PM

The aeromotive fpr won't go over 70psi I believe

riceisnice · 07-19-2008, 06:47 PM

Mine leaked down really fast after I turned it off too. I just replaced the o-ring with a slightly bigger one and it fixed the problem.

Gmanigio · 07-19-2008, 07:16 PM

Quote: Originally Posted by riceisnice

Mine leaked down really fast after I turned it off too. I just replaced the o-ring with a slightly bigger one and it fixed the problem.

I just placed an order for 4 oversized o-ring, dont know which size I need so I ordered 4 diff. sizes. Hope it helps....

Gmanigio · 07-19-2008, 07:17 PM

Quote: Originally Posted by bpsrt4

The aeromotive fpr won't go over 70psi I believe

Yea, 70 or 75, dont remember.

But I will only hit 60-62, so its still not hitting max FP @ WOT

roadflare16 · 07-21-2008, 12:22 PM

wait, replaced the o-ring for what, the factory fpr? i just replaced my fuel pump, again, since the walbro I had died after about 100 miles, and that big rubber o-ring for the fpr had easily grown to twice it's normal size and wouldn't go back on, so I had to cut about 2in out of it, and it was still overlapping itself a good inch, but before that it held pressure beautifully, now it drops down to 20psi immediately and then slowly drops from there. anybody know where to get a replacement o-ring for that?

Gmanigio · 07-21-2008, 10:51 PM

Quote: Originally Posted by roadflare16

wait, replaced the o-ring for what, the factory fpr? i just replaced my fuel pump, again, since the walbro I had died after about 100 miles, and that big rubber o-ring for the fpr had easily grown to twice it's normal size and wouldn't go back on, so I had to cut about 2in out of it, and it was still overlapping itself a good inch, but before that it held pressure beautifully, now it drops down to 20psi immediately and then slowly drops from there. anybody know where to get a replacement o-ring for that?

Your talking about the spongy thing?? That ussually went back to normal size after the gas dries up.

Atleast you hold 20psi