i need to replace the fuel pressure regulator on my TPI car . but i dont want to fool with the cheap *** diaphram that seems to be all we can get . i want the WHOLE thing . who uses what ? and where can i get one . summit only offers diaphrams and FPR covers

 

i just did the BBK adjustable housing and the Echlin(napa) diaphragm. $50 + $90. works great!

 

exactly what i DONT want . i need to find the entire thing .

 

well than i suggest hopping in a deloreon and driving 88 mph to 1985

 

@Rusty - The only other part is the base block of aluminum that is part of the fuel rail assembly. That + diaphragm + cover = FPR. You can re-use the stock cover, or get an adjustable one. That leaves finding a quality replacement diaphragm. Don't forget the special anti-tamper T8? torx driver that is needed, and does come with most (all?) AFPR covers.

Or, watch the classifieds to get a used fuel rail assembly.
Or, modify the stock rails to use an external, aftermarket AFPR.
Or, get aftermarket fuel rails + aftermarket AFPR.

 

actually , have you heard that brand new de lorians are being built as i type this . AND the projected cost is less than $100,000. something like that with a turbo LS3. hmmmmmm

 

Street and Performance, located in Mena, Az. has an OEM unit complete in their on line catalog. Nice folks to deal with I might add.

 

S&P is an Mena, AR... Arkansas not Arizona.

Google found this catalog page, producing part # 17112281 for $156/166/176 for natural/polished/chrome. It is discontinued anywhere else. Considering a new diaphragm is $70-$80, the asking price, if still available, isn't bad.

 

Correct MoJoe

 

so , if a FPR will hold vaccuum . is it a safe bet it isnt leaking ?? and i think the extra fuel is coming from my cold start injector. anyone know if south bay has them ??

 

I have one or two. $20 paypal'd and shipped.

 

I replaced my FPR as it was leaking into the plenum, I replaced with a brand new ac delco, no more leaks however car does not hold fuel pressure, (and runs like poop) after turned off, drops instantly to 0, I followed instructions and pinched the fuel lines to determine if it was a check valve or pump issue

what is a good brand to purchase for a FPR, or if someone has one and willing to ship to Canada please let me know, would like one with adjustable pressure, but as long as it works that is fine

 

I had the same problem. Disassemble the unit and inspeçt the flow control valve, flat disc, and the SS seat in the fuel well. The diaphragm disc has to be mirror like smooth no machined marks if it not absolutely smooth fuel under pressure escapes past disc and the stainless steel port back in the fuel rail.

 

We have the stock adjustable regulator and the diaphragm. Take a look. If it is what you are looking for just let us know.

 

 

Exactly the same problem I'm having. Longer crank before it starts, but runs good though. I can't really decide if it's less peppy than before I replaced it, but it might be. Pressure drops when pump stops. The stock diaphragm's button was mirror smooth, the new had machine marks on it. I saved my stock torn diaphragm and might remove the new one and try to swap the button on the new diaphragm for the stock mirror finished one.

Which one is that? I bought the adjustable one and the vacuum hose pipe interfered with the diaphragm top metal spring seat on the inside of the cover, so i had to take it out and put the stock cover back. It now sits unused in a drawer, is it still the same design?. Also the diaphragm I bought from you is the one with visible machine marks on the button that gives me issues. Which brand are your FPR diaphragms?

(Side note: I'm very satisfied with the Bosch III TPI injectors I bought from you though.)

edit:
Have you checked that you put the big vacuum hose for the brake booster back on the plenum? Easy to forget, and the car runs like **** when it's off. I missed that, and only caught it because I replaced the plugs&wires after the FPR. I didn't hear a hiss or anything.

 

I wish you would have contacted us. We want you to be happy. We sell the regulators and the diaphragms every day. What marks are you referring to? The diaphragm is the stock GM.

 

south bay fuel injectors has it they are a sponsored vendor here

 

I'm planning to remove the plenum again very soon, to try and replace only the "button" on the new regulator with the one from the old torn stock regulator to see if it fixes the problem, I'll try to get a photo of them side by side to show you what I'm referring to.

This image is from a parts vendor page, the marks are pretty rough and looks just like them but "round" instead of straight, and they could be felt with your fingernail.

On the old stock regulator which was removed because of a torn rubber diaphragm, the button/disc had a mirror blank finish, and if you drag your fingernail on it, it feels like a glass mirror (perfectly smooth).

Before I put it in the second time when I had a little bit of a panic because the diaphragm broke in my dad's parking lot 190 miles from home and no choice but to use this regulator, I "wet polished" it a bit myself with very fine emery cloth to get it at least a little bit more flat.

The car runs ok now, but the pressure still drops immediatly (to zero in about 3-4 seconds) when the pump shuts off, and I have a feeling it's a little down on power, and the crank is longer than with the stock regulator before it starts because the pressure takes longer to build.

With the old regulator, pressure held perfectly at 50 psi for at least 10 minutes, and the cranking time for engine start was next to nothing.

 

did you purchase the regulator and diaphragm from us? Why don't you return whatever you purchased from us.
Want to see what the deal is.

 

Yes I got them from you (diaphragm and billet adjustable fuel pressure regulator), ordered them at the same time as my injectors (which are great by the way!). The problem is that the diaphragm i got from you is installed in the car right now and if I send it away it won't be driveable, and spring is coming closer! I don't know what i'll have to pay for shipping either because I live in Sweden..

I'll get photos of the stuff while it's apart anyway. If I can't get pressure to hold even when I've tried swapped the discs, I'll probably buy a new diaphragm again. Then I could send the old one back to you so you can have a look at it.

 

keep me posted ok?

 

Just got home after a few hours in the garage! I brought a real camera too, and got some really good photos!

My theory proved right, there is definitely something wrong with the regulator i got from you, you can see it very clearly in the photos that it doesn't seal. I took photos of it side by side with the old one so you can compare.



Mirror blank disc to the left, bad disc to the right.




Literally mirror blank, you can see the camera lens reflection on the disc.




Bad disc with marks on it, and now that it's been in the engine for some miles you can see that it doesn't seal all the way around.

I managed to do a half-assed swap of the discs and put the regulator from south bay back in the car with the old disc. It holds a very small pressure now, but not as much as with the old regulator. Unfortunately I cannot start the car right now to try the cranking time, but I will report back further when the snow is gone here.

If you want to send me another diaphragm as Goodwill, it would be much appreciated. Since i work as a mechanic, I don't trust the half-assed repair I did so I need a new regulator to keep in the car regardless if this works, so that I'm prepared for a roadside repair.

If you think you can send me another one, it would be cool if you could take a quick look at it before shipping so that one is okay.

 

send me your name ad shipping address and i'll send you another.

 

Will do, thank you!

 

So I finally got around to installing a new adjustable FPR from southbay

great quality product, only prob is they are a PITA to adjust once the plenum is installed

The car runs much better however once turned off the pressure drops to 0 still, it does drop much slower, but is at 0 within 20 seconds of shutting off car, last FPR it was instantly at 0

 

Pinch off the return line, and see if pressure still bleeds off just as quickly. If it does, it's the check valve in the pump, not the regulator.

 

Pressure holds with return pinched, so new pump?

What should pressure be at while running?

I set it to bout 45 with hose off regulator and then connect vacuum and it runs at bout 40 is that correct how it dropped?

 

If the pressure holds with the return line pinched, but not with the return line free, it's the regulator that doesn't hold pressure. pump is OK.

 

another bad regulator WTF?

the adjustable one I got from southbay looks just like the one described in this thread, its all scratched up, not smooth, do I have the same problem?

 

What regulator is scratched up????? Are you referring to the diaphragm. We get them directly from GM! I can show you a pic of everyone that we get. They are not shiny

 

yes the diaphram is scratched just like keykey's

I am just looking for direction, is it the regulator or pump, is there a way I can tell, other than what has been suggested?

 

It doesn't matter if there are tiny "scratches", they just can't be rough to the feel. South Bay sent me a new one, and it wasn't mirror blank, it looked "scratched" too, but it works like it should. So just because it's not blank doesn't mean it's faulty.

If you don't have a longer cranking time than normal it doesn't really matter that the pressure drops slightly when the pump shuts off.

The problem with my old one was some kind of machining fault that made it not seal att all which led to longer cranking time and lower fuel pressure when pump was operating.

 

OK, but why do people say that if you pinch the return line and pressure holds then it is a defective FPR and not the check valve?

 

When you pinch the RETURN line you remove the FPR from the list of variables. Even if the FPR leaks, the pinched line blocks flow.

If the pressure drops, then either the check valve must have failed (fuel back flows the feed line), OR one or more injectors leaked out the fuel. So, you cannot tell if the FPR is ALSO leaking.

Therefore, if the pressure HOLDS, ...
... the check valve on the fuel pump side prevents back flow down the feed line.
... none of the injectors leaked.
... and the pinched return line holds pressure on the return side.

Therefore, when you un-pinch the return line, and the fuel pressure drops, it must be the FPR that "leaked" the pressure.

 

OK, so does anyone know where one can get a working FPR?

 

Any auto parts store should carry it, like RockAuto for instance? The corvette TPI uses the same diaphragm AFAIK.

 

Update

fuel pressure still drops like a rock when key off -- oh well i guess

ended up taking car to local shop that actually knows how to work on a TPI, long story short, 2 new MAF relays and a new, expensive MAF, not purchased from Rock Auto and wow the car runs amazing

 

Good news . As I've understood it, it doesn't really matter if pressure drops when key turned off, as long as you have SOME pressure holding for starting, and full pressure as long as the pump is running. My car runs great now, and the pressure doesn't hold like it did with the factory regulator.