acidpad

Ok, heres whats happening. it seems rather randomly, sometimes on start sometimes after ive been driving around, some of my plugs will stop firing and theyre flooded. ive been told this is most likely my fuel pressure regulator. i have a 91 camaro 3.1 with MPFI and im under the understanding that in order to replace the fuel pressure reg, i have to replace the whole fuel rail, and the only place i can find a new fuel rail is at a dealership for $433. does anyone else have any insight on this ? is there a way to put an aftermarked reg on and bypass the old one ? any input will help.

Thanks

Trickster

You can buy the spring and diaphram for the fuel pressure regulator at autozone, advance auto parts and a few other places fairly cheap. The most expensive store for it so far has been NAPA. On the other hand, you can go to a junkyard and buy the whole rail fairly cheap when you can find them.

PS: on a side note, if the plugs are fouled it's more likely that one or more of your injectors are shot rather than your fuel pressure regulator. If the regulator was bad, the fuel would be going back to the fuel tank, not the plugs.

The Trickster!!!!!!!!!!!!!

Project: 85 2.8 bird

IF the regulator is bad, fuel could also ride up the vacuum tube into the intake.

not good :nono:

acidpad

injectors are new, replaced them 6 months ago.

Trickster

It doesn't matter, one or two of them could still be bad. Think about it, how is fuel going to get to the spark plugs unless it goes through the injectors. That is the only opening that the fuel can go through. Get a fuel pressure gage and put on your rail to check your fuel pressure. BTW, what size injectors did you replace the old ones with?

The Trickster!!!!!!!!!!!!

V6sucker

have you double checked vacc leaks? a faulty signal to...
1 the actual regulator
2 the MAP
will cause probs.
have you checked your coil?
your ignition modulator?
your wires?
the gap on your plugs?
your actual fuel pressure?
your timing?

no need to replace the fuel rail, but if something has gotten into it, you have much worse things to worry about.
You can use a regulator for a L98 3rd gen, it WILL FIT. I am using a gasket from one on my V6.

Faulty regulators will tend to not allow the car to run when they fail/are about to fail. They will not allow pressure to build up in the rail to distribute the fuel propperly.

Also any/ or a mix of the above things will cause your car to run rich.
I run .040 gap on my plugs, and 13* on timing. 3.1 5 speed.
Your really not giving a whole lot of info, but if you go over what I listed, I bet you will find 1 if not more things out of line.

CaliCamaroRS

Obviously you are not thinking about it. Very often, the diaphram in the fuel pressure regulator rips and fuel gets sucked through the vacuum line, into the intake manifold, and into all the cylinders. There you go-- fuel in the chamber without going through the injector.

With that being said, I don't think the fuel pressure regulator is the original posters problem. Typically, when the regulator is bad, symptoms will be:

-Extended crank time due to flooding
-Running rough due to too much fuel
-Stalling usually when coming to a stop

Acidpad made no mention of 2/3 of the symptoms so I wouldn't go throwing a $433 part at it just yet.

Trickster

So put a pressure tester on the rail and see if it is holding pressure. Both when he primes it and while it is running. Also to test your theory about the fuel going into the chamber from the vaccum line, disconnect it while the engine is running and see if any fuel comes out.

The Trickster!!!!!!!!!

CaliCamaroRS

Its not a theory. I had at least 4-5 cars THIS WEEK ALONE with ripped diaphrams. This also dillutes your motor oil with fuel. <--Not good

The best way to test it is to prime the fuel pump, then pull the vacuum line off and check for fuel. If there is no fuel, then put a hand vacuum pump on the regulator and see if you can suck fuel out.

I've seen a handful of regulators that would not leak unless the engine was hot.

acidpad

all 3 of those issues are present

what im trying to find out is if theres a way to fix the reg without buying a whole new rail.

Dale

iTrader: (12)

You dont have to buy a rail. You can buy a regulator at parts store, a kit that has many funky tips (as 1 is needed to take reg off), and replace it.

If nothing else, get a holly adjustable for a v8, its "the same" as ours, along with the bit kit.

TomP

Yeah, the GM service manual says "the pressure regulator is not a servicable item"- that's bull. All you need is the "security torx bit set" to remove the special torx screws. Or, I've heard you can take a hammer & punch, and pound down the little nubs in the center of the torx screws so you can use a regular torx set. I think if you went to GM, they would just try to sell you a rail, as opposed to the "aftermarket" which actually makes the part.

How much is a diaphragm, anyway?

Oh Dale I just re-read your message- the regulator kit Comes with the special bits? That's cool! Is that kit just the diaphragm, or does it come with extra pieces?

Dale

iTrader: (12)

No no, it doesnt come with the kit, I had to find the kit at local parts store.

I needed the kit for something else, but found out it came with the bit I needed to do that

Parts counter does sell the regulator. If not, summit does the holly one, but only for a v8, yea right It fits ours too

acidpad

ok, so i went to autozone and got their fuel pressure reg that they had listed for my car and go to put it on , and it was not the right part, by far. I fear that is also the case with the holley one that im being pointed to, so im uploading a picture of my fuel rail with pressure reg. 2 pictures follow: i believe (correct me if im wrong) that the "regulator" is consistant of both parts sticking up out of the rail here. now the real question remains, how do i get this / these parts, or how do i rebuild them, bypass them, or otherwise get the car running

acidpad

second picture:

Trickster

The component that is sold at autozone and other parts stores is the diaphragm that is inside the black cap on the fuel rail. To get the cap or cover off, you will need a special torx bit with a hole in the center of it. These are also sold at the parts stores fairly cheap (about a dollar or two). When you put it all back together again, the torque on these screws is 14 inch pounds.

The Trickster!!!!!!!!!!!

acidpad

got the torx bits, and i took the black cap off and looked at the diaphragm, and it looked pretty messed up. By just replacing the diaphragm, should that resolve the issues ?

Trickster

Yes, and when putting the regulator back together make sure that you hold the cap down on the rail until you get all the screws in and run down. Otherwise that little swivel piece could get cocked at an angle in there.

The Trickster!!!!!

acidpad

i cant find the diaphragm anywhere, i was up at autozone, and they didnt have it, and i checked advance auto parts online and havent been able to find it there either .... any tips ?

Trickster

Ok,
Believe it or not, I went to gmpartsdirect.com and checked on the fuel pressure regulator for your car and looked a picture of it. It is different from the one on the V8 engines. Even though they both have the black cap with the diaphram inside, and that is the fuel pressure regulator for the V8's. The fuel pressure regulator for the V6's is actually the little block with the schraeder valve in it that sits next to the black cap with the diaphram. If you still need the diaphram, go to AutoZone and give them this part number and brand name. GP-Sorenson 800-122, the price is $24.99. It is a fuel pressure regulator kit. It is listed under the 1989 rs 2.8 liter engine but it will work in your case. Advance Auto Parts also carry them in the Niehof and Borg-Warner brand names at a little higher price. Blamed if you don't learn something new every day. Sorry if you have been led astray

The Trickster!!!!!!!!!!!!

acidpad

would you assume that the diaphragm could still be the cause of my problems ?

TomP

Actually, that's the fuel Block. The regulator is the same as the v8's. Gmpartsdirect probably just has the wrong picture.

Dale's telling the truth about the Holley, and -any- AFPR meant for a TPI v8.


The regulator is the circular object with the vacuum line fitting. Under the cap is the diaphragm.

JoshDT91

iTrader: (1)

Here is a picture of the part Trickster is talking about made by GP-Sorenson.

Dale

iTrader: (12)

and heres hollys.

http://store.summitracing.com/partde...LY%2D512%2D501

JoshDT91

iTrader: (1)

That Holley one looks a lot nicer and built better. Too bad the regulator sits under my plenum though.

Lee7

i have the Holley Adjustable one on my V6.

Trickster

Hello Tomp,

I am just as confused as everybody else about the picture shown on gmpartsdirect.com. I agree that what they show is the fuel block, but they list it as the fuel pressure regulator. Listed below is the link for the page that I went to. It is listed as item 4 for the V8 & V6 cars.

http://www.gmpartsdirect.com/partsvoice/frameset.cfm


The Trickster!!!!!!!!!!!!

Dale

iTrader: (12)

gmpartsdirect site is wrong. It shows the FWD intake for us RWD engines. DON'T GO BY PICTURES ALONE

acidpad

i just wanted to thank everyone for the help .... shes back up and running healthy, i got the GP-Sorenson 800-122 at autozone and it was exactly what i needed. Thanks again.

CaliCamaroRS

Change your oil and filter. If the diaphram was ripped then you have fuel contaminated oil. <---Not good

camaro_junkie

Alright, this post, back from the dead. But oh so useful.

So now I know what to get for the FPR and I'll also be getting a fuel rail O-ring kit, but is there a gasket available for the fuel block on the fuel rail?

camaro_junkie

Anyone? I guess everyone's all caught up in the turbo talk.

JoshDT91

iTrader: (1)

Camaro Junkie: There should be a gasket for the fuel block to fuel rail. If it does not come with a new fuel block then look for a gasket kit for the fuel rail. I could not find one online but you might want to try a Chevy dealer for the gasket if you cannot find another source.

Gumby

Wasn't someone around here making an adjustable one for our cars???

camaro_junkie

JoshDT91: Thanks for the reply. I'll check up on the kits and go to the dealer if I need to.

Gumby: I'm talking about the fuel block. There's nothing to adjust. You can get an AFPR. There is one from Holley available at SummitRacing (mentioned above in this post).

Gumby

No someone was making / working on a modded stock fitting regulators that was adjustable. I am sure of it. It was a while ago though. 4-6 months

camaro_junkie

But we are talking about the regulator right? I was looking for a gasket for the fuel block (where the schraeder valve is).

kretos

hey camaro junkie, try calling best buy perfromance in surrey, they should be able to find the part, talk to dave he'll help you find it

confucius101

hey you guy's wouldn't happen to have any summit and or holly part numbers would you ?

(i'm lost somewhere in the many many many pages of summit online)

camaro_junkie

If you are looking for the Holley adjustable FPR, I'll repeat the link from above.

acidpad

if you dont need the adjustable one, go to a local parts store, and just get one from there. For some reason, most places dont have one listed for the 3.1, but if you tell them you have a 2.8, they have it, and its the same one. thats what i got, and it works fine.