83 944 n/a

Hey guys I'm having trouble with my 83 n/a getting carbon build up badly and believe me when I say she doesn't get babied so it's not just a "blow it out" situation. I've replaced all the injectors, fuel rail, fuel pressure regulator, fuel damper, all with in 7k miles a few hundred miles back I noticed my o2 sensor was completely unplugged, I plugged it back in and I still get a nice carbon smell but only after ragging on it. Also it has a hesitation on cold starts but not at idle only when I first take off for about 5 minutes. Also replaced the throttle position sensor and swapped 2 different Air flow meters an still getting same issue. Could a bad sensor be causing all of this carbon build up though? I used seafoam in the vacuum line yesterday and boy did she smoke like a freight train, but seems to have helped her run better a little. Any input would be appreciated! Thanks!

John D.

Moved into the 944 Forum for you...

Thanks RV..!

John D.

konakat

Could be a weak spark. Might want to take a look at your ignition system. If you still have the original coil, that would be a cheap and prudent fix. A lot of people use the MSD Blaster 2 with good results for just $60.

Jfrahm

How do you know you have carbon buildup? Borescope? What is a "carbon smell?"

If you are running pig rich and blowing black smoke the O2 sensor is probably dead as they cannot survive long like that, your coolant temp sensor (for the DME) might also be bad and running the car rich.

NoRush993/951

Try using Shell or BP 93 gas.