Black o2 sensor and plugs, Running rich???

[staehlin180]

Okay, so i tried searching for a couple days, but to no avail, I have a 1991 turbo, with a fresh rebuild (less than 10k miles). While replacing the exhaust manifold gasket, I found that the o2 sensor and the plugs were very black (carbon?) i didn't find any oil on the plugs. I think i maybe running a tad rich. Ive been driving myself nuts trying to figure out what could be causing this/how to fix this. I already picked up a new o2 sensor, and I'm running autolite copper plugs, a K&N fipk (inside of afm looks a little oily, nothing too excessive) and a greddy profec a boost controller any help would be greatly appreciated, thanks.

 

[staehlin180]

anyone?????

 

[jetjock]

Well, if the exhaust manifold gasket was leaking it would have been running rich so that could explain what you found. You may not be rich now. That said whenever the engine is suspected of being out of fuel control it can be easily checked by following the TSRM procedure for O2 sensor testing. The same check can be made using Vf with the ECU in diag mode and the engine off idle.

 

[MDCmotorsports]

^ To add to the electrical checks.... check the "obviously simple mechanical" first.


*-BOOST LEAK-*