Aeromotive AFPR pressure drops to zero

[Calan]

immediately when I shut off the car. I've heard some people say it's normal..others say it's not. Even a couple vendors I talked to disagree.

Does anyone that REALLY knows what they are talking about care to jump in here and clarify this, and if it shouldn't be happening...how do I fix it?

I installed it about a year ago and it seems to work properly except for this (and the car takes some cranking to start). I'm going to pressurize it and see if it rises at 1:1 in a day or so, but figured I'd work on this issue in the mean time.

BTW - I saw a post on this a while back, but can't seem to find it now.

 

[FORMONTOYA]

Although I'm no expert, but I can let you know my experience...

While I agree there is a lot of discussion regarding this topic (and many threads to read through), the general consensus is that the Aeromotive AFPR will NOT hold pressure indefinitely. It will gradually over time fall to 0PSI. With that said, it "should" hold pressure for a reasonable amount of time.

Mine for instance, will immediately drop 5-10PSI upon shutoff and then slowly drop to 0PSI within an hour or so. When I first installed the fuel setup (re-wired 255, Aeromotive 13109, injectors, etc) it would immediately fall to 0PSI and take a bit longer to "fire up" than before the install as you mentioned. After a little reading/looking I found that I had twisted the o-ring in the fuel pump hat...after fixing that my system operates as I described and "fires up" as it should.

 

[SBR Joe]

It depends, not generally "bad". I have seen some walbro pumps hold the pressure for a good bit afte rthe car was shut down, i have also seen some not. My walbro 255hp holds about 25-30 psi and slowly drops to zero after about 10 minutes, but my Supra pump in my 1g drops to 0 within a minute or two after shutting down. Its nothing to really worry about though.


Joe

 

[FORMONTOYA]

Most of the discussions I have seen have people changing the fuel pump AND AFPR at the same time. I'm really curious if the issue of not holding pressure is related to the AFPR or to the Walbro pump. The o-ring that fits in the "hat" never really seemed to fit properly for my tastes.

I will agree that it is not a dramatically big issue, just something that bugs the piss out of you because it doesn't operate the way you think it should.

 

[CTP]

Mine holds pressure for a good 10-15 minutes after shut off. The only time it didn't was when I had a very small fuel leak at the filter. However, I have seen other cars that lose pressure immediately and they didn't have any obvious fuel leaks. It doesn't seem normal to me, but who's to say...

 

[Calan]

Most of the discussions I have seen have people changing the fuel pump AND AFPR at the same time.

Yep...that's me

I'm really curious if the issue of not holding pressure is related to the AFPR or to the Walbro pump. The o-ring that fits in the "hat" never really seemed to fit properly for my tastes.

There was an o-ring?
I don't remember that to be honest, but I've drank a few beers and slept since then.

I will agree that it is not a dramatically big issue, just something that bugs the piss out of you because it doesn't operate the way you think it should.

Exactly. I'm anal enough as it is, and can't stand it when something doesn't work as it should.