Still haven't found a definitive reason why the HC & CO are high (CO VERY high) but maybe I just did.

Drove the car ('84 242Ti w/lambda) for 2 weeks running Techron through it (1 1/2 tanks) thinking the injectors may be leaky (esp. cold start) staying in 3rd gear a lot to keep the revs up to try and burn any crud off the CAT.

Anyway, I was pulling the plugs to check their condition this AM and found an exhaust leak at #3 port. I thought the ticking I had was coming from the valves but now, maybe not. Plug boot and plug's outer ceramic are coated in black soot.

So am I all wet in thinking the exhaust leak could be screwing with the O2 sensor readings enough to throw things off?

A recap is:
it passed back in January with borderline high CO but everything else was well in spec. Ran Sea Foam through it and then it sat for 6 mos. 'til August when it failed due to high HC and very high (6%) CO. Drained old gas & flushed w/new + Techron. All ign. parts are new, TB & IAC cleaned. Kjet NOT worked on or diddled with. New air & fuel filters. New vac & intake hoses (except silicone hose off turbo). Turbo throws a little oil but not a lot. Plugs are light grey in color and clean (some black buildup around inside of thread body but insulators and cathode are clean).

PS I'm thinking of getting a portable exhaust gas analyzer off EBay. Does anyone have any recommendations/experience with small hand-held units such as Fluke, Snap-On or UEI?


'94 945T (daughter co-opted it for college, used to be mine)
'99 S80 (mom-in-law's)
'88 240DL (son's)
'84 242Ti (commuter)
'89 560SL (wifemobile)
'88 300TE (for sale)
'68 GT500KR (under restoration)
--
Bob K