Does anyone know of a better fuel pressure regulator diaphragm? I have a 350 with the Edelbrock Pro-flo MPFI, which uses the same regulator as a stock TPI. It seems about every 2 years the diaphragm starts leaking, and it's going again now. I think this is the 3rd time now. I think it may have something to do with the fact that all the gas at local stations is 10% ethanol during the winter months here in MN. I can tell the rubber is just breaking down. I've just been getting stock replacements from a local Corvette Specialties speed shop. Does anyone know of one that will last more than 2 years? Thanks for any help!!!

 

The holley adjustable unit comes with a diaphram thats different than stock

 

Hmm... Just a guess... but its not a problem with the stock OEM diaphram. You've got something else going on here. Just about every GM MPFI product uses the same fpr diaphram as TPI cars. Very seldom do they go bad. Make sure you're using a genuine GM part. If problems continue start looking at either whats wrong with the system you're using, or where you may have made a mistake installing the regulator.

 

Thanks for the replies guys. Do you know where I might be able to get a genuine GM diaphragm? The first time it started leaking, I checked at some local dealerships, and I was told that GM only sells the regulators complete. I don't remember how much they were, but I remember they were not cheap.

I don't really see how it could be assembled wrong. The Edelbrock systems come completely assembled. And when I replaced it, I just took it apart and reassembled it all the same way. I'm not saying it's impossible that it's wrong, but it just doesn't seem that complicated. And do you think it's possible that it could work fine for 2 years and then go bad because of mis-assembly? But it sounds like you might know something I don't. Have you heard of something similar before? Or maybe I'd be better off just breaking down and buying the whole regulator just to be sure? I guess I'd rather buy a GM one than an adjustable one. The pulsewidth is adjustable on this system, so I don't really need an adjustable regulator for tuning.

 

So I take it nobody knows of a better diaphragm for the stock FPR? Or knows how to get a GM diaphragm without having to buy the entire regulator? Please let us know if you do.

 

The only way I got a new one was to buy the Holley regulator which I love.

 

Any local parts store will carry them. I have destroyed one, so has my buddy. They are available at your local PepBoys or Autozone. They are made out of a rubber type material and do tend to get brittle over the years.

 

Bowtienut, I've a 85 TPI, and I replaced my diaphram this past summer while my injectors were out being cleaned and flowed. Mine was leaking too. When I opened it up, the rubber diaphram material was all flakey and dried out. I believe this stuff helped to clog my injectors. I tried a Chevy dealer also, and was faced with the same issue of needing to buy the whole assembly for $$$$$. I did'nt need the whole thing, since I was making a homemade AFPR with the stock cover for the unit. So, I went to Checker, and got one that was reasonably priced and looks EXACTLY like the GM part. I believe the brand was either Standard or National. These are both reputable brands, hopefully OEM level quality. It works great. I agree that 10 % ethynol fuel probably don't help matters. either. Hope this helps.

 

Just an update for anyone interested. It was indeed the PF regulator diaphragm. Again! Got a new one from a local Wardsports Corvette shop. Talked to the owner quite a bit about it, and he said he hasn't found a solution either. He replaces ALOT of them for customers. His only advice is to avoid the ethanol-ized gas as much as possible. Especially before the vehicle goes into storage. Maybe this will help someone out there.

 

Bringing this back from the dead hoping that someone might have a better answer… I’ve had 2 oem ones fail in as many years and am looking to replace another. I hate pulling this thing apart to get at it…

 

Resurrecting this thread from the dead because I just removed my diaphragm and the rubber was all rotted and decayed. Anyone have a clue as to what causes this?

 

additives in the gas... most likely the ethanol they started using the last few years.