dizwiz24

If anyone has a '93 lt1, and they are 100% positive it still has the original, facttory, OEM ICM (ignition control module), please step in side....


For anyone not familiar what this is, this is attached to a heat sink and your igntion coil. Should be on the passenger head of your engine.

Can someone look at theirs and tell me what series of white letters/ numbers are on it? It doesnt need removed or anything to see these numbers.

For example, mine says: 799 2B20, horizontally right next to the stamped 'GM' logo. Which is stamped into the plastic. It also has '466' stamped in the plastic vertically

If yours doesnt have a stamped 'GM' logo, its probably not OEM.

Any help is appreciated!

gravyhound

First I would like to say that when I was tring to figure out my own problem I have found that the lt1 motor is the same and has the same parts like ICM and ECM and so on for the years of 1992, 1993 corvette and 1993 F body and I have found that other years and modles like impala, roadmaster and so on are not compatible even though they are physically identical. So the ICM on My 1992 vette is the same as yours and my white numbers are 409 4g06 and mine also has 466 on it and the Map sensor has the 466 on it also. I was wondering what you are tring to figure out?

dizwiz24

Thank you. Yes, that series of numbers is what Im looking for. If anyone else (w/ a 93 lt1) came chime in too, Id appreciate.


Are you positive that is what came with the car. (I dont know what the number should read, all I know is that the ICM has different p/n's depending on whether you have a 92-93, 94, or 96. Either one of these will still fit the connector and heat sink of any lt1. However, there are some different ECM's (particularly from 92-93 to 94-95, and then 96)).

gravyhound

I do not know what the numbers on these ICM'S are but they are NOT part numbers, and the numbers on all of them are all different and will tell you nothing, I have allready been down this road. The correct AC/DELCO OE P/N# for the 1992-1993 corvette and 1993 F body with the LT1 is D1971A and is not on the ICM its self. and remember the later years are not compatible but they are Identical.

rklessdriver

Why are they not compatible?

When the factory original ICM in my 92 took a dump I use the ICM from a 94 Z28 to trouble shoot and it worked fine....
Will

dizwiz24

Will , one thing to remember is the ecm from 92-93. And 94 thru 96 pcm is entirely different.

It may work fine, but since this thing controls spark retard/advance, id hate to chance it

WVZR-1

For starters - YES there are different ICM's for '92 - '96 MY Corvettes:

'92-'93 "original" would/should have an ID of 799 which is the last three digits of the OE "original" at the time. That OE was 16132799.

'94-'95 "original" would/should have an ID of 409 which is the last three of the OE "original" at the time. That OE was 16191409

'96 "original" would/should have an ID of 599 which is the last three digits of the OE at the time. Original OE was at the time was 16201599.

The other information:

The 2B20 is a date code that is most frequently determined to be year(2),month(B),day(20). Year is self explanatory, month A - M (skipping I) and the day. That should hold true thru the '90's and there were changes 2000 and beyond.

The 409 that "gravyhound" refers to is likely a '94MY with a date code 4G06. The date code indicates it's not likely "original"!

F body cars are consistent with the Corvette applications.

gravyhound

From what I have found is looking the part up on the net or at a parts store 92 and 93 Y and 93 F bodys come up with AC. P/N d1971a and other years and modles come up with different P/N's like D1986a for an Impala ss so something is different about them and the crossover charts say it is not compatable with a 1992 corvette

gravyhound

my car is a 92 but the motor came out of a 95 caprice wagon that was recked with low mi. so my ICM is OE to the motor and I just found that out do to this info that they did not change it over, Now I must go hunt down some mexicans.

dizwiz24

Thank you so very much!

Maybe the other ones would work fine, but Id hate to chance it.

I rely upon this thing to retard timing when the boost comes on, so Im to track down what is correct for my year car (and ECM)

rklessdriver

I hear you. I also ended up buying the correct (expensive) one listed for a 92-93 but I would really like to find out what the specific difference is.....

BTW I bought mine from Chris May as Superior Chevy and it was like $114 back in August of 2010.... The number on it is 799 5B04.
Will