If I have to replace ICM

[LarryK]

Can someone tell me where the ICM is located on my 90 Reatta and what all is involved in replacing it.  tks  LK

[2seater]

Look at the top of the page, category labeled "How to Guides". Under that heading are myriad subjects and repair topics. Under electrical, sub heading ignition, there is a professional "how to" video on diagnosing, disassembling and replacing the coil pack and ICM

[Padgett]

I always replace the Magnavox unit with a later Delco. Plug and play.

[DPS.01]

I took Padgett’s advice…

1993 Buick Regal donor. 
 

OEM (with failed potting compound):

Donor:

 

Thanks for the excellent write up and cross reference information contained on this website. 

 

Want to use the concept on a 1987 Grand National… uses the same Magnavox Coil Pack, but ignition control module is different (but fails the same way)… may not be possible, that search continues. 

Edited March 4, 2023 by DPS.01

[Padgett]

What does the GN connector look like ? May be able to make an adapter.

[DPS.01]

On 3/6/2023 at 11:39 AM, Padgett said:

What does the GN connector look like ? May be able to make an adapter.

I will PM you.

thanks. 

 

 

[2seater]

If I remember correctly, the GN version of the 3.8 used a cam sensor driven in conjunction with the oil pump, similar to a distributor. It was also used to determine #1 cylinder for ignition and the shutter wheel(s) on the crank pulley are different. There was also an early version of the three coil waste spark Delco ignition from 1986 on the 3.8 engines, the coils being the same as what the 3800 uses but the ICM is different. I think the Delco # for the early version is D1946A and the later is D1977A. I don't know if that might improve the odds of getting a different ignition?