944 Turbo running like doo doo

[billy mild]

Okay first off my car drives fine seems to run a little rich. I replaced the cap and rotor and plugs. This seemed to have helped a little bit.

Here are the symptoms: When you go WOT the car runs great up until the upper rpm range and then kind of surges like its fuel related almost like a misfire and its not the same everytime.

Off Boost the car runs great no problem. Get to 1.5 bar on the boost gauge. At least it looks like that.

Car puts out a little black smoke sometimes. Like its really rich.

When warmed up and I rev it while sitting still the car will rev up fine but kind of drop really low idle then return to normal.

Now on my old 924S the car would run good, but did the same thing with black smoke and spitting out black stuff out of the tailpipe. I replaced the FPR and it was fine after that.

Could these be signs of it running really rich or what? I think I might replace the FPR and see how it does but if there is something else I could try that would be great.

[billy mild]

The boost isn't getting high only because i can't rev it all the way to til redline. I get to about 4 or 4500 rpm and it starts to like not go anymore. Its almost like its starved for fuel, but acts like its running really rich. Today at 2 stop lights the car just died. I was able to restart no problem.

It is kind of making a noise from the back that sounds like a dieing cat. I think it might be the fuel pump its not all the time, but when its there you can hear.

I have replaced the plugs cap and rotor already. I was thinking of replacing the FPR and seeing if that is what is causing this problem.

[billy mild]

I do not have a fuel pressure gauge on the end of the fuel rail. Tonight I will be checking the fuel pressure with a gauge. I believe its a snap on. Hopefully this will give me a clue.

Wanted to give another update. What I have found is that when I am first driving the car meaning just started it up, and I go to open it up the car runs good not great, but better than normal. Then once its warmed up or it has been driven a bit the car will not be running good, and the fuel pump will be making noise. My question is could the fuel pump be going bad and work great for a second then the next be falling on its face?

Also would the FPR play a role at all then. What I am going to try to do is put that fuel pressure gauge on and see what it does on a cold idle. Then drive it around the block or a little bit then come back and see what its registering at. Would that be good to check the fuel pump or FPR?


This is my posting over from rennlist.com I am looking for as many eyes as possible to try and get this car running.

If your in the KC, MO area let me know.

[nize]

perhaps the idle stabilizer is on the fritz?

might also be an intermittently faulty tps.

[DannoXYZ]

Several different problems:

1. idle dropping low and coming back up is just throttle-plate/TPS adjustment

2. high-RPM/on-boost issue is most likely speed & reference sensors.


Fuel problems such as fuel-pump, filter, etc. typically results in running-lean conditions, not rich.

[billy mild]

The FPR was bad. It runs great now.