86 951 Driver

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. I will be driving 4 hours tomorrow so any advice will be great.

Sorry for the long post.

86 951 Driver

BUMP

spammajamma

are the plug wires original equipment?

931guru

Replace plugs, wires, distributor cap and rotor.

Tom M'Guinn

1.5 bar is a bit low for a stock car. You may have a vacuum leak, which let's boost (i.e., metered air) out -- causing it to be rich. Could be lots of other things as well, but that's one of the most common problems. There are lots of places that can leak, so sometimes its best just to remove each hose and examine it closely (tears can be virtually impossibe to see unless you flex the rubber and expose them) -- and those crimp-style hose clamps under the manifold get loose as the rubber ages and shrinks under them.

86 951 Driver

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.

ehall

Fuel pump won't make any noise until it gets stressed. Change it.

ehall

actually, test it first.

86 951 Driver

How would I test it? The guy who I bought the car from was a mechanic and said it ran fine, but now its not. If the fuel pump was bad wouldn't that just die completely. Out of boost it will drive just fine.

86 951 Driver

Could this be the fuel filter. Mine is old and could use to be replaced. I have a new one, but I couldn't figure out how to put it on.

ryanm6100

may want to try FPR, mine did something similar (though it "died" at like 1700rpm) when it was shot. Few weeks later the TPS went as well.

86 951 Driver

Could I get a 3 bar FPR and it will run like stock or not? I would hate to buy a 2.5 bar one and only upgrade it later, but if thats what I have to do its what I have to do.

Paulyy

did you change the leads? what colour where the spark plugs when removed?
coil?

sounds like the same issue as mine.

ryanm6100

Actually I need to edit my post above, I confused it with the TPS failure.

It would be fine until about 4k and then sputter/die. That was the FPR.

86 951 Driver

What do you mean by leads? The old spark plugs were black and sooty when I removed them. It could be an ignition problem, but for some reason I think its a fuel issue.