Hi All,
It's been a few years since I last posted here. I started my 89 951 the other day after it sat for a few weeks, and it stumbles, will hardly idle and won't rev past 2k or so. Blows lots of black exhaust, too. I'm thinking it's the fuel pressure regulator or pump, but what's the easiest way to find out? The shop manual calls for pressure between 2.3 and 2.7 bar. I don't have a pressure gauge, but I'm thinking of buying one at Sears to check it. Would a Craftsman gauge be accurate enough to detect a problem? Any other thoughts or suggestions? BTW the engine is all stock.
Thanks a bunch!

Dave Barker

 

running very rich, check all the vac lines, see if one has come off.

 

the gas might have gone bad?

87951

 

Check (in the order with highest possibility)

- Vacuum leak: pressure test the system - Check all air hoses & clamps.
- Faulty/leaky FPR (or line going to it) - Check Fuel Pressure - Inspect FPR, if vacuum hose smells like fuel, the regulator can be bad and fuel is getting sucked in to intake via vacuum hose.
- Leaky Fuel Dampner
- Bad Engine Temp Sensor
- Bad O2 sensor (disconnect see if it fixes the problem)
- AFM gone bad.
- Injectors harness
- Leaky injector?

If none of the above, I'll start looking at the DME..

There is no simple answer, you just have to check all potential causes till you find the problem.