I was doing some routine maintenience on the 87 today and found that the thermosensor wasn't hooked up....so i hooked it up and now a lot of the problems i was having went away...BUT here's a NEW one... The damn motor will blue smoke at startup now...It doesn't when the thing it unplugged but does while it's hooked up. WHY? Is my OMP malfunctioning? The motor is a rebuilt and has about 40k.... The thermo has been unhooked since rebuild .....thanks for the help.

 

Are you sure about the blue smoke color?

I would expect to see white steam condensation on startup in your climate.

With the sensor unplugged & the ECU seeing freezing cold, it would start extra rich, which would reduce the initial visible steam.

With everything working, cold start initial steam is good, unless it smells like coolant.

Along those lines, a new rebuild will burn more oil during break in, & the extra rich startup could have been masking it before.

(edit) I just noticed the 40K - Hmmm.

 

yeah i am positive it's blue/grey It doesn't make much sense to me cause blue means oil but the car doesn't burn a lot of oil at all like half a quart per oil change.....

 

It's fuel dripping out the injectors overnight, diluting the oil around the rubber o'rings.....and burning off when you start. Ain't OMP related in any way. If you have a fuel cut switch, rev the engine up above three grand and hold it there when you cut the switch off. Let the engine die. Turn the key off first....then turn the fuel cut switch back to on. Get up the next morning and start the engine and see if you still have the blue smoke on startup. Probably won't. Go worry about something else.