My friend in New orleans just did a LT1 swap in his 87 monte using a painless wiring harness running a 93 ECM with a 94 LT1.
The problem is he got the car running but it would not idle below
2000 rpm (but it automatically goes to 2000)and is giving him a IC FAILURE OR SHORTED light . and it seems to run great like that but will not idle down,and he said today car will not even start at all...
We are waiting for his akm cable to come in ,probably monday.
Oh yeah car has LT4 hot cam , roller rockers and headers being only mods.

Any help would be greatly appreciated,
Thanks.
I will post this on Engine swap board as well.

 

Sounds like the idle air controller is messed up....
bad wiring or needs replacing

 

Ohhh IC = idle air? I thought ignition control.
Great he said its sucking an awful amount of air.
Thanks,will try.

 

A buddy had a similar problem but was idleing at 1800. After the idle air control module was changed, the problem was solved. These things can't be cleaned by the way.

 

Well changed IAC motor - no go still.
And Code 41 is ignition control failure, any suggestion on what would cause this?