What a way to end the year over in Bill’s driveway working on my 928! Thanks again Bill… I’ll get a pressure regulator ordered up on Tuesday – looks like I need P/N 928 110 198 04, runs around $90 bucks at 928 International

 

A very good driveway to be in !!! Happy New Year !!!!

 

I pulled the pressure regulator and to me it seems bad, if I plug one side and blow in the other I have air flowing out of the fitting that goes back to the tank. Bosch part # on the old one is 0 280 160 297 which looks to cross to the Porsche # Now for the hard part, I had something fall into the belly pan I better go find what dropped down there Happy New Year to everyone…

 

I wish I had a nickel for each item I've dropped in my belly pan. You'll find it.
Happy New Year

 

I only put the bellypan on when I think I'm done working on the car for at least a year....

 

I hear you Bill I did find what dropped and to my surprise it looks to be one of the 19mm bell housing bolts. Ouch that a big one to work loose. I have the fuel pressure regulator out and will order the replacement today. Then I’ll be ready for the new Boge Reds, rotors etc

 

Thats great i Hope this fixes the problem , please let us know, Stan

 

I finally got done reading this entire thread. What a great diagnosis! Sure sounds like you guys got this narrowed down to the culprit. PLease post the outcome. I'm putting this in my hard start folder.

 

Matt
Great results....Bill can fix anything!!

Let us know when you put the new one in!

 

Hey Guys,

Will do, I talked with Mark A. at 928 International this afternoon and just got the UPS Ship notice so the part is on the way

I'll keep you posted

 

Uhoh. Remember how careful we were to recheck the flywheel and TT clamp bolts when we did your torque tube. Looks like we weren't so careful on the bellhousing bolts.

 

89' Euro S4

I've been reading your thread and it sounds like you have the same symptoms as I've been having. I started with the easy stuff and narrowed it down to the pressure regulator after reading some other posts with the same issue. I was having trouble starting the car hot and cold and it just didn't seem to be running well.

I started by replacing the fuel filter, fuel pump check valve, Temp II Sensor, tested all the resistance levels to the LH and EZK. Everything checked out OK. However, the problem was still there. Last summer I pulled the injectors and had them cleaned and balanced, so I ruled them out.

I kept suspecting that the FPR was bad but was also worried about a bad brain. Didn't want that!
I finally pulled the vacuum hose on the FPR and the Dampners and there was alot of gas coming out of the vacuum hole on the FPR! No gas from the Dampners so I figured it must be the FPR.

Last night I replaced most of the relays and the FPR and Voila! Ran it hot and restarted fine. Started it up this morning cold and the car runs like a dream! Cost me a few hundred bucks but the car runs better than it ever has.

I suspect you have the same problem. Good Luck!

Brent

 

Brent:

Similar except we have no fuel coming out the vacuum holes. We just have a FPR that is able to maintain pressure when the pump is running but is not completely sealing the return orifice when the pump is turned off.

If we all would just have followed the WSM testing procedure, we could have avoided replacing a lot of other parts, as the FPR return is the FIRST thing you check if the fuel pressure does not hold. I was focusing on it being either the check valve or the injectors and overlooked the FPR until I checked the WSM when neither of the former fixed the issue.

 

Bill,

Looking forward to hearing how the new FPR works! As I mentioned your issues sounded very similar to mine. If the new part works, excellent, otherwise back to the drawing board! And your right, the WSM testing procedures do save a lot of headaches.

Brent

 

The fuel pressure regulator arrived today and I installed it tonight, started the car to check for fuel leaks and everything looks good. I need to pull the belly pan to reinstall that darn bolt. I’ll button it up tomorrow and report back.

At some point I’ll need to get with Bill and put his fuel gauge on there to see if we solved the 60# to Zero lbs of pressure in 15 seconds problem , well that and hope she starts right up warm…