'87 Iroc Overheating and Idling Bad.....

[webbcals]

I am new here. Good to meet you all! I found this forum while trying to find an answer to me overheating problem. I a post here about the possible causes of overheating problems. I have an '87 Iroc with 5.7 TPI. My two fans do not come on when needed. The guy I bought the car from had a jumper on one of the two relays that turns the fan on so it would come on when the ignition was on. I have found each of the two relays fo rthe two fans and I have verified they are both good. I can't find the temp. switch that picks up the relays. I'm sure there has to be one somewhere for that. Any help would be appreciated!

That is the beginning of my problems......the other owner also removed the smog pump. Looks like he just started grabbing hoses and electrical connections and pitched them.The car does run well and strong but has an idle that ranges from 500 to 1000 rpm's. I have looked for all possible vacuum leaks and hooked back up everything that had a place fo rthe connection. At this point I am getting flustered because I need this car driveable as soon as possible . Again, I would appreciate any help here!

Thanks!

[tcfco2005]

from what i think i know there are a few temp sensors the two that i know of are located on the intake where the thermostat is at(where the radiator hole goes into the engine. and the other one on my car was under the manifold by the front spark plug on the drivers side. i had to go under the car to get to it. thats all i can think of

[tcfco2005]

oh and about the ideling thats where my car idels and my car seems finr

[webbcals]

Does yours go up and down from 500-1000rpm? Mine will not hold steady.

[webbcals]

I know about the two on the front by the thermostat. I'll hunt for the other near the spark plug. Thanks for your input!

[Morley]

One switch for the fan is in the passenger side head, between # 4 & 6 cylinders. That one is a temprature switch. The other fan is controlled by your A/C, it comes on when you turn on the A/C.
First thing to do when troubleshooting an erratic idle is to set minimum air.
Key on engine off put a jumper across pins A & B of the ALDL (top RH 2 pins), wait 15 seconds then remove the connector from the IAC. Next remove the jumper and start the car. Put it in drive (if auto) and set the "idle" to 500 RPM. Shut the car off (back in park) and reconnect the IAC.
Next step is to set the TPS. Key on engine off hook a digital volt meter to pins A & B of the TPS connector with it still hooked to the TPS. The reading should be 0.54V +/- 0.17V, adjust the sensor by loosening the 2 mounting screws and rotate the sensor to get the desired reading. Retighten the screws and verify the voltage reading.
Remove the meter and start the car and check your idle.

[webbcals]

Thanks for the good info. That helps me understand more about how the cooling system works.

I will do the procedures for checking the idle too. I hope that helps it out.

Thanks again for the help!