Idling problem after headgasket fix

[95eviltalon]

I have searched for hours and have not found anyone with this problem so hopefully someone can give some advice on what i should look for.

Basically what happened is my head gasket blew about a week ago, so i removed the head and took it to be flattened while i waited for the new gasket to arrive, while the head was off we removed the cruise control vacuum module but left the black box with the cable going to the throttle body attached. We have put the head back on the car with new 272 cams installed straight up (the cams were installed this way before the head gasket when and the car ran just fine).

The problem is now the car is running but it refuses to idle properly, it will start up and idle at around 1k for about 20-30 seconds and then it will rise to 2k or more and stay there even if the car is at operating temperature. i have set the BISS screw using the proper method (ground timing and adjust) and it still will not idle properly. Anyone who has had this problem or has any ideas of what it could be please let me know!

 

[nuclearr]

sounds like the IAC need to be adjusted.

 

[95eviltalon]

i forgot to add that if i rev the car the RPM will drop slower than normal and then hold at whatever it was idling at.

 

[stevo911]

That block box with the cable from the cruise control did you take the cover off to make sure the cruise cable isnt stuck in the spindle for the pedal and throttle cable?

 

[95eviltalon]

the cruise cable is no longer there, only the cable going to the throttle body

 

[stevo911]

If you unplug your throttle position switch does it idle high but steady?

 

[95eviltalon]

if i unplug the TPS it does a very slow idle surge, it will idle at 1k rise to 2k for about 15 seconds or more, and drop back to 1k

 

[stevo911]

Sounds to me like the IAC if you unplug that is anything affected?

 

[95eviltalon]

The IAC is the plug under the throttle body by the throttle butterfly right? if so then no nothing changes if i unplug that, the coolant lines are bypassed to it.

 

[stevo911]

Cooling lines are bypassed to the FIAV which is right beside it. I am 99% sure your IAC is gone possibly if you have a multimeter to can check the resistance? This should be same directions for a 2G also Idle Surge FAQ go to the part under ISC

 

[95eviltalon]

Yeah that is the plug i was refering to, When i unplug it nothing changes. Ill test it tomorrow.

 

[stevo911]

Ok chances are im not going to be around tomorrow until the night if it works out for you send me a PM and let me know.

 

[95eviltalon]

ok, im unsure that this is going to be the cause of the problem because this was unplugged before the head came off and the car idled fine.

 

[stevo911]

Head was also shot? That ISC motor controls your idle without that working it will not idle.

 

[95eviltalon]

Yeah the head was shot, it needed to be resurfaced. I will try replacing this IAC with a good used unit to see if it changes anything, but as i said it was not plugged in before the head gasket went out and the car ran / idled fine

 

[95eviltalon]

Well here is an update, I drove the car to work this morning and it goes down the road great, I noticed that when driving or giving it throttle when I come to a light I idles right about 3k rpm. I have no clue what is going on