89 Carrera running problem (long)
 

This morning on way to work, car suddenly developed radical idle (stalling to 3k), and breaking up under load. Limped home with car as I hadn't got to far and let it cool. Just started it again, this time with O2 disconnected, and car now idles at approx. 1k, but is blowing black smoke (rich). Moving the throttle still causes it to break up.
I replaced CHT one month ago, car has new magencors and caps and plugs.
Unrelated, I just finished replacing lubing and replacing torn C/V joint boots (nasty job).
Anyone have an ideas what could have so suddenly let go? Thanks for any help

Paul

Pulled the plugs and they were sooty (black) as expected from running rich. Checked for any visible damage, vacuum leaks and AFM has tension.
So, what is making it run so rich suddenly?

Is it running like complete crap? Bucking under load? etc. I had that problem with my C2 and it turned out to be the ISV.

Jeff

Jeff,

Thanks, I'll check it. Yes, car runs (barely) like crap under load. I recently installed new CHT sensor and I'll recheck it to make sure it has not come loose. Beyond CHT sensor and ISV, what else controls mixture?

Check with Steve Wong onthis forum. he might be able to help. I can turn wrenches with the best of them but my motronic diagnostic skills are somewhat limitted.
On the C2 it was an easier check because the computer stored fault codes.

Jeff