ICM Malfunctioning

[lbear]

Driving home the engine started to misfire. Got home and put it on the scanner and it showed cylinders 1&4 misfiring. I swapped out that coil pack. Yet it continued to misfire showing 1&4 misfire.

What is the best ICM to purchase? Rock Auto has an OEM GM for $225, Standard Motor Products for $170, Wells for $120, WAI Global for $60. The WAI Global has a "lifetime warranty". The others are 3-5 years and 30k-50k miles

 

[HotZ28]

I would go to a pick&pull (or JY) & get one from a compatible vehicle for less than $50. bucks & buy two of them so you have a spare. Most of the JY & pick&pull in my area offer a free 30-day return if you have a problem! There are many GM cars that use the same ICM. Look at the list below to show compatibility.

BUICK	ALLURE	2005-2009
BUICK	CENTURY	1993
BUICK	LACROSSE	2005-2009
BUICK	LESABRE	1992-2005
BUICK	LUCERNE	2006-2008
BUICK	PARK AVENUE	1991-2005
BUICK	REATTA	1991
BUICK	REGAL	1990-2004
BUICK	RIVIERA	1990-1999
BUICK	SKYLARK	1993
CHEVROLET	CAMARO	1995-2002
CHEVROLET	IMPALA	2000-2005
CHEVROLET	LUMINA	1998-1999
CHEVROLET	LUMINA APV	1992-1996
CHEVROLET	MONTE CARLO	1998-2005
OLDSMOBILE	88	1992-1999
OLDSMOBILE	98	1992-1996
OLDSMOBILE	ACHIEVA	1993
OLDSMOBILE	CUTLASS CIERA	1993
OLDSMOBILE	CUTLASS CRUISER	1993
OLDSMOBILE	INTRIGUE	1998-1999
OLDSMOBILE	LSS	1996-1999
OLDSMOBILE	REGENCY	1997-1998
OLDSMOBILE	SILHOUETTE	1992-1995
OLDSMOBILE	TORONADO	1991-1992
PONTIAC	BONNEVILLE	1992-2005
PONTIAC	FIREBIRD	1995-2002
PONTIAC	GRAND AM	1993
PONTIAC	GRAND PRIX	1997-2008
PONTIAC	TRANS SPORT	1992-1995

 

[RD_Atlanta]

While the cylinders 1 & 4 misfire could be due to an ICM failure (& its always good to have a working spare), it could also be caused by an open circuit in either 1 or 4 in the high voltage secondary circuit (either 1 or 4 spark plug wire) or (1 or 4 spark plugs). I had a cylinders 1 & 4 misfire and it was the #4 spark plug.

 

[lbear]

Also, the thermal paste. Does it go underneath the new ICM and then also on top of the ICM, where the coil packs connect?

 

[HotZ28]

Also, the thermal paste. Does it go underneath the new ICM and then also on top of the ICM, where the coil packs connect?

It goes underneath between the ICM & mounting bracket. In addition, the following links may help you to diagnose the problem.

How To Test The Ignition Coil Pack -Misfire Troubleshooting Tests (GM 3.8L)

How To Test The Ignition Coil Pack -Misfire Troubleshooting Tests (GM 3.8L).

easyautodiagnostics.com

GM 3.8L Ignition Control Module And Crank (3X, 18X) Sensor Test

GM 3.8L Index of Articles

easyautodiagnostics.com

 

[lbear]

Once I get it running right again. I was thinking of changing out the oil since it was misfiring on 2 cylinders. That's a decent amount of unburned fuel that went down into the oil.

I got the new ICM and will install it today. Im going to test the old one at O'Reilly's. They have a machine that will test it.

 

[RD_Atlanta]

Once I get it running right again. I was thinking of changing out the oil since it was misfiring on 2 cylinders. That's a decent amount of unburned fuel that went down into the oil.

I got the new ICM and will install it today. Im going to test the old one at O'Reilly's. They have a machine that will test it.

If you could, try to shoot us a small video of the test they do.

 

[lbear]

If you could, try to shoot us a small video of the test they do.

 

[RD_Atlanta]

Were you able to swap the ICM?

 

[lbear]

Were you able to swap the ICM?

Yes, installed the new Standard Products ICM and the engine fired right up and ran great. No misfires. Ran scanner and showed 0 misfires. The Standard ICM is Made in the USA. I put the thermal paste on the backside of the ICM which will help pull heat from the ICM onto the heat sink metal plate it sits on.

Lifetime Warranty on the ICM from O'Reilly so it's a peace of mind in case it ever goes out. I am not out $200 and stuck on the road. There are over 6,000 O'Reilly's in the USA.

 

[02LTD2.0]

I had a Standard Motor Products ICM fail one month after the 2 year warranty. Luckily I still had the original ICM in my trunk and was back on the road in a few minutes.

 

[lbear]

I had a Standard Motor Products ICM fail one month after the 2 year warranty. Luckily I still had the original ICM in my trunk and was back on the road in a few minutes.

Standard bumped their warranty to 5 years (50k miles) on the ICMs. They had/have a "T" series which only has a 1 year warranty but the O'Reilly one is the "Premier" series which is 5 years.

Even so, I will get a spare and keep it in the trunk.

Did you put the THERMAL PASTE on the backside of the ICM? That is an important step to help the heat sink plate it sits on absorb the heat the unit puts out when in use. Otherwise the chipboard in the ICM gets too overheated and will fail.