Darn, I finally got this car running good and now the mixture has suddenly gone off the deep end rich. The plugs are coal black, there is black smoke coming out of the tail pipe if I gun the engine and there is black soot coming from the tail pipe as well.

The auxillary fan coolant temp switch went bad a couple weeks ago (fan was running continuously) and I replaced it. I read some threads which spoke of the coolant temp sensor going bad and the electro-hydraulic actuator needing adjusting. I found the resistance chart for the temp sensor at various temps, but it is not clear if the resistance should be measured between the two posts of the temp sensor or each post and ground. Does anyone know? Any other commentary is welcome.

Thanks,

Bob Kopicki
'67 TR-4a
'76 GMC C-15
'85 XJ-6
'87 300e
'97 VW Cabrio