How to check for a faulty FPR (Fuel Pressure Regulator) and replace it

[chickenrob]

sweeto! Just changed mine out, it was really bad, gas was spurting out the vacuum connection. I was having trouble starting not only hot but also cold (but it was better in the winter for whatever reason). A word of caution, the car did backfire WHEN I was checking the fpr, scared the crap out of me! This car sounds like a firecracker when it backfires, once I was driving some friends to camp and I acually asked them if they had firecrackers in their luggage we didn't know what the sound was. Also, I did attempt to releive the fule pressure, and I thought I had (some gas squirted out of the pressure release valve) but when I poped off the fpr, a miniature eruption of gas occured that also caught me off guard. The car was also sputtering a lot when first started, and this seems to have helped this too. Thanks for the great post!

[Ranger]

Originally Posted by eurumbaev

Great post. I seem to be having an opposite problem. My '94 Eldorado, 168k, has been having difficulty starting in the morning after sitting overnight, but once started, throughout the day starts on the dot. It seemed to be progressing worse and worse, untill today I wasn't able to start at all! Is it possible that a bad FPR might be causing this type of problem as well(even thought the symptom seem opposite), or would it be more likely the fuel pump? Any suggestions would be appreciated. Thanks!

I would suspect the fuel pump. Put a guage on the fuel rail and get a fuel pressure reading.

[SkarTisu]

Is there a special trick to getting at the fastening bolt that attaches the FPR to the bracket on the 4.9's? This has to be the DUMBEST design I've ever seen for hanging a part! It looks like I may have to pull the fuel rail, but the FSM doesn't describe the procedure from what I can find!

Frustrating! I really don't want to pay someone else to do this since the part itself is simple, and easy to see.

Thanks for any insight!

[100]

Originally Posted by SkarTisu

Is there a special trick to getting at the fastening bolt that attaches the FPR to the bracket on the 4.9's? This has to be the DUMBEST design I've ever seen for hanging a part! It looks like I may have to pull the fuel rail, but the FSM doesn't describe the procedure from what I can find!

Frustrating! I really don't want to pay someone else to do this since the part itself is simple, and easy to see.

Thanks for any insight!

I agree with you that it is a dumb design, but you do not need to remove the rail to replace the FPR. I did lift the rail when I did it first time (2 yrs ago). But now I know how to do it without lifting the rail. I used a torx (I forgot the right size, I think it is the same as that holding the fuel rail near the inlet and outlet) bit and a small wrench to turn. There is enough space to stick a torx bit there. Not too bad.

Yes, the aftermarket FPR didn't last long, only for 2 yrs and started leak! Now I installed one from ACDelco.

[SkarTisu]

The bolt fastening the FPR to the rail is a torx? What size?

I could see how you could get a small torx bit in there. Clever!

[100]

Yes, on my 95 SDV with a 4.9, it is a torx. Unfortunately, I do not remember the right size. But as I said, the torx holding the fuel rail inlet and outlet on the engine is the same torx that is facing up, so you can easily verify the size of the torx bit there and stick the same bit under the FPR.

Good luck.

[SkarTisu]

Very good! Thanks for the tip....I'll let you know how it goes once I've tried it.

[Gearheaad43]

I changed out the FPR on the 97 STS..... Took a total of about 10 minutes... Easy as PIE!!! .. Wow!! I wish other GM cars were that easy!! LOL... The FPR I used was a GP Sorensen P/N 800-319, manufactured by Standard Motor Products, Inc.

Noticed a bit more power on tap!!! And no fuel smell "UGH" in the cabin.. YES!!

[SkarTisu]

Finally got mine swapped out. Here are some tricks I learned along the way.

- FPR location on the 4.9s is between the distributor and the throttle body. You have to remove the airbox to see it
- Remove the distributor cap AND rotor to get an unobstructed shot at the FPR fixing screw. I found it easier to mark all the plug wires, remove those, as well as the white connector on the distributor cap so I could fully move it out of the way
- The correct Torx key size for the fixing screw is a T27
- Using a Torx L-key, not a Torx bit, was the winning combination. I couldn't get a Torx bit secure on the screw to turn it
- Don't forget to fish the o-ring out of the old FPR and transfer it to the new one. Starting the car without that o-ring was a BIG (but not flaming) surprise!
- Even though you released fuel system pressure before disconnecting the old FPR (RIGHT?!) you'll still get fuel spillage out of the rail when you remove the FPR. Put that cigarette out first! Also, put something underneath the FPR to catch the fuel that will spill out. I'd guess that a tablespoon of fuel leaked out on mine.

I'm very pleased with the results. I haven't had a chance to test a "heat soaked" start yet, which was a problem before, but driveability especially at very light throttle application is much better. She pulls away from a stop smoothly now instead of a slight lurch and stumble. Fuel mileage appears to be improved, but I'll need to drive a whole tank to be sure. I think I got some power back (I should have anyway) but it's not a night-and-day difference. She jumps when you put the coals to her, though!

[97Concours1]

I just thought I'd let everyone know about a problem that I had that could be common on other cars. I pulled the vac line off of the FPR (fuel pressure reg) to check for gas coming out of it. No gas (good), but I also noticed there was no vacuum in the line either. I pulled the short little vacuum line off the intake and it was clear. I tried to poke a wire through the intake manifold nipple and couldn't even force it though. I finally took the intake completely off to see what was going on. I took the throttle body off and found a 1/4 inch of built up nasty carbon all over the back of the throttle plate and inside the intake. This also covered the vacuum port for the fuel pressure regulator. It actually took a drill to get it opened up, even after I scraped all the carbon off the inside!

This vacuum line is important for proper fuel mixture. If it is clogged, fuel mileage could suffer and the engine could run lean or rich causing other problems. My car ran better instantly after fixing this.

[porkfarm]

Glad to hear your ride is doing better. This is one of the reasons why I use seafoam every now and then. I try my best not to get the black build up on any intake part. Started with my Jetta TDI, those things can close up with 75K on the clock, but you can bypass the EGR with VAGCOM.

[JimD]

Great catch. This one should be moved to the Tech Tips forum.

[Ranger]

This is why it is important to clean the TB once a year.

I'll merge this thread with the FPR thread in the Tech Tips section.

[dcmage]

Having several issues with my 96 deville. First when engine is cold (overnight) it usually takes 3 to 7 attempts to start. At which point it runs rough for 30 seconds or so the smooths out. Second is that it is now stalling. First it started stalling when you relieced the fuel peddle coming to a stop. Now it is stalling even when going down the road. To restart you have to turn the key off, turn it back on listen for the pump to p[rime then start engine, even then it sometimes take a couple minutes to start back up. If i turn the key on and let it set sor a minute I hear the intial priming of the pump last several seconds then within about 10 seconds I hear a moter running(asume it is fuel pump) but it sounds like it is not picking up fuel (starving) and it does not stop till i turn off the key. When the engine dies I hear this same sound. It is coming form the area of the fuel pump. It does not sound the same as when the fuel pump first primes itself.

The engine stalling is getting worse. it will sometimes only run for a minute before stalling. By pumping the gas I can sometimes keep it running at about 300 to 400 rpms for a minute or 2.

[Ranger]

This section is for Tech Tips, not questions. Please post it in the proper forum.