so i put the good old OBD I computer into my 1984 trans am and the computer pulled up issues with the cooling saying coolant temp signal high or open, Loop closed and exhaust O2 Rich but the what confuses me is how the temp when read on the computer is -40 on a start after a long drive and how the ilde plays from 600rpm to 1000rpm

heres a pic of a wire i suspect may be the prob connected to to what i think is the cooling sensor unit
[IMG][/IMG]

any answers are appreciated

 

Sounds like you have a bad sensor or a wiring issue. The -40 reading would indicate that the coolant sensor is unplugged. So check your wiring and make sure there isnt any opens or breaks in the wiring and make sure the connector is ok and making connection. If all checks ok, I would suspect the coolant sensor is bad. You can use a ohm meter to check the sensor. Readings will vary on temp.

 

unplug it and check the wires- i have the same sensor on my 84 T Type, and it did exactly like you describe.. i was trying to unplug the sensor with it running to see if it would change the way it ran and it smoothed out as soon as i touched the wires.. i looked a little closer and the insulation on the wires had shrunk back from the plug and the wires were touching.. a little bit of carb cleaner to clean it up and some of that self sealing friction tape on the wires to isolate them from each other fixed it right up.

 

I had to look at your 89 IROC as I thought it was mine for a few seconds.. Sharp looking car..