LT1 Erratic Idle
Thread Starter
Registered User
Joined: Sep 2012
Posts: 15
Likes: 0
From: Downers Grove
LT1 Erratic Idle Long time lurker here and current member over on Thirdgen, I'm a college student at Lewis University working on my Airframe & Power Plant Certificate and Business Degree, so I'm very hands on. Thanks in advance for all the help.
Scott
Background on the car:
1995 Z28 T-56. This is my first LT1, I bought the car with the top half of the motor sitting in the hatch and basically all the gaskets there up are new. No egr or air pump and they are properly blocked off.
The car runs great minus the fact that when it's been running a while (operating temp at least) the idle is horrible. The tach will basically jump wildly and the car feels like it wants to die but never does.
I've replaced plugs and wires already so I'm suspecting the ICM is going. The opti is supossed to be new and looks like it but I haven't been adventurous enough to take it apart. I just rebuilt my injectors (bosch ford blue tops all ohm at 15.4 and were flow matched) haven't found any vacuum leaks, ground are good and I'm stumped.
Scott
Background on the car:
1995 Z28 T-56. This is my first LT1, I bought the car with the top half of the motor sitting in the hatch and basically all the gaskets there up are new. No egr or air pump and they are properly blocked off.
The car runs great minus the fact that when it's been running a while (operating temp at least) the idle is horrible. The tach will basically jump wildly and the car feels like it wants to die but never does.
I've replaced plugs and wires already so I'm suspecting the ICM is going. The opti is supossed to be new and looks like it but I haven't been adventurous enough to take it apart. I just rebuilt my injectors (bosch ford blue tops all ohm at 15.4 and were flow matched) haven't found any vacuum leaks, ground are good and I'm stumped.
TECH Enthusiast
Joined: Aug 2010
Posts: 543
Likes: 0
From: New Hampshire
Long time lurker here and current member over on Thirdgen, I'm a college student at Lewis University working on my Airframe & Power Plant Certificate and Business Degree, so I'm very hands on. Thanks in advance for all the help.
Scott
Background on the car:
1995 Z28 T-56. This is my first LT1, I bought the car with the top half of the motor sitting in the hatch and basically all the gaskets there up are new. No egr or air pump and they are properly blocked off.
The car runs great minus the fact that when it's been running a while (operating temp at least) the idle is horrible. The tach will basically jump wildly and the car feels like it wants to die but never does.
I've replaced plugs and wires already so I'm suspecting the ICM is going. The opti is supossed to be new and looks like it but I haven't been adventurous enough to take it apart. I just rebuilt my injectors (bosch ford blue tops all ohm at 15.4 and were flow matched) haven't found any vacuum leaks, ground are good and I'm stumped.
Scott
Background on the car:
1995 Z28 T-56. This is my first LT1, I bought the car with the top half of the motor sitting in the hatch and basically all the gaskets there up are new. No egr or air pump and they are properly blocked off.
The car runs great minus the fact that when it's been running a while (operating temp at least) the idle is horrible. The tach will basically jump wildly and the car feels like it wants to die but never does.
I've replaced plugs and wires already so I'm suspecting the ICM is going. The opti is supossed to be new and looks like it but I haven't been adventurous enough to take it apart. I just rebuilt my injectors (bosch ford blue tops all ohm at 15.4 and were flow matched) haven't found any vacuum leaks, ground are good and I'm stumped.
Does the car still pull in the upper rpms when your having the idle issues?
Thread Starter
Registered User
Joined: Sep 2012
Posts: 15
Likes: 0
From: Downers Grove
So far I found one melted plug wire and my coil was not spaced off of te cylinder head. The idle doesn't hunt, the tach flickers. Which pointed towards an ignition problem not the iac. Hasnt acted up yet since I've changed the above.
I'd say it was just the plug wire if it was melted. I've never seen anyone about spacing the coil off the head but I do know the ICM Cooling mod is quite popular and it was the one good decision the prior owners of my car made.
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Good Luck to you.
Tom
