Motor swap idle issue.

[g4ebguy90]

Hi guys, I did look through some threads by other people but it's a little different.

I just got done swapping heads from a 1990 6 bolt, to a 91 6 bolt. I got the car to start after a couple cranks.

Now it just sits there, and goes vroom pa vroom pa vroom pa.

Like 1500 to 1000 then it repeats. I noticed if I turned the cam sensor, it either made it faster or slower but didn't stop it, I assume this is due to ignition timing.

So, I unplugged the IAC, and it didn't do a darn thing... But I thought that was normal?

and ideas

Also there is a sensor on the thermostat housing that I broke . I don't know what it is though, I assume cooling fan switch but idk, it had a dark peice of rubber covering the whole thing.

 

[92AWDHX40]

Terry's Talon Troubleshooting Tips #3 - Fast Idle (aka. Idle Surge) i would start here.

 

[g4ebguy90]

After reading that, I tested the coils on the ISC they are good, and again If i unplug it idle does not change.

 

[manifestmessiah]

You may have broken your coolant temperature sensor, which tells the ecu when to exit out of warm up mode. As far as the idle sure you can start by trying to pin point vacuum leaks by spraying starting fluid on your vacuum hoses. You could also clean your throttle body, it might help out a bit.