Help Please.....1986 928 Running Rich!

bxtech · 07:48 PM

Hello all,

My 1986 928 all of a sudden started running excessively rich. Fouling plugs, black smoke, flooding. Pulling the spark plugs........all 8 are wet. Was thinking that the problem might be the coolant temp sensor. I changed the sensor and there was no difference.

I remember reading about someone with this exact problem years ago, but I can't seem to find the posting. I'm not sure if it was even on this forum.

Has anyone had a similar problem like this? Anybody that can offer some advice or experience would be greatly appreciated!

Thanks in advance!

JhwShark · JhwShark's Garage

I have an earlier model but search posts for "running rich"...odds are it is a sensor...O2 or other crank/cam type position sensor. Others will chime in with precise info that is confirmed in some of the previous threads.
Jon

porken · 06-26-2010, 09:08 AM

Check if the Temp II sensor wiring is good.

>1K ohms cold, 300ish hot, between pins 2 and 25 at the LH connector. Check with the engine cold and hot.

Pinouts:

(EZF_LH22_32V.pdf)

(EZF_LH22_16V.pdf)

jstobo · 06-26-2010, 10:06 AM

Check your MAF. If it fails the computer goes into limp home mode which has 2 settings. One for under 2000 rpm and one for 2000 rpm+. It will run rich in this mode.

bxtech · 06-27-2010, 07:45 AM

Thanks everyone for the input!

JhW.....I keep thinking that it could be some sort of sensor as well! Coolant temp sensor was the first thought. It has a recent new 02 sensor. Not sure about the crank sensor or if it may cause this, but will do a bit more research.

porken......Thanks for the suggestion and thanks very much for the diagrams. I'm going to check out the wiring. Would make sense if there's a short somewhere.

jstobo.......Thanks. The MAF was also one of the things I was suspecting too! Thanks again for the info. Makes sense that this could be the problem too!

What would i do without all the helpful people on this forum?!

Maleficio · Maleficio's Garage

Quote:

Originally Posted by bxtech

Thanks everyone for the input!

What would i do without all the helpful people on this forum?!

Become a severe alcoholic (like me).