What kills icm?

[92berettabase]

Own a 1992 beretta base 3.1 liter v6 engine w/ 370,000 miles. Gone through 2 icms between 2009 and 2012. Engine is turning over but not catching. Making the classic
r-r-r-r-r-r-r sound, but not firing. No spark. Before I replace yet another icm I would like to know what destroys them. Beretta has killed both new and used icms.

Oct. 2009 original icm goes out and is replaced with a brand new one.
June 2012 the brand new one goes out and is replaced with a used one.
Oct. 2012 the used one is not firing (and if replaced) will make icm #4.

Any ideas?

[themixer]

the heat from the exhaust manifold kills them, try getting one off a newer 3100/3400 as they are mounted on the top on the engine and not near the heat. hope this helps.

[3X00-Modified]

Just getting the ICM from a 3100/3400 does not change how it mounts. It's exactly the same part. he has to physically move it as well as possibly extend wires on the harness to do this.

[berettaboi]

yes, may be time to move it up top. a very worthwhile "mod" if you have to replace it that often... make sure you are getting stock ac delco (or dephi?) icms and coils. they seem to be the most reliable and best part.

[themixer]

I was not saying how it mounts was going to change, just that the top mounted used part would be in better condition than getting one from an older 3.1/2.8.

[Money pit Beretta]

BWD or Delco. If you are messing around with cheap ones your waisting your money. Also clean the back of the ICM(with rubbing alcohol) and the mount it sits on. The mount acts as a heat sink. On the back of the ICM put some computer CPU heat sink grease(use a credit card to spread it thin). Be sure to clean all the crud off the back of the mount too.

[lolwut]

Just getting the ICM from a 3100/3400 does not change how it mounts. It's exactly the same part. he has to physically move it as well as possibly extend wires on the harness to do this.

John had to move my ICM for the headers to fit; he moved it and the coils to the firewall and used two nearly perfectly spaced holes (I think for firewall mounted cruise control). According to him the only wire that had to be extended was the ground- all others he just pulled out of the loom and re-routed. Plug wires were flipped (short to rear bank long to front bank).

[Beretta1234567]

I'm not sure if this helps but maybe the CPS is partially faulty causing intermittent problems?

Or maybe one of your coils are messed up on the primary enough; causing it to burn up the ICM?

These both happened to me before. I changed my ICM for it to fail after a couple months, then I replaced all 3 coils with the second one and it was fine.
Intermittent CPS is no fun, that's something you usually expect to just work.

If I did all that and I still have it breaking, I would probably change out my ECM after checking all the wires are okay.

[Rettax3]

The under-the-manifold-behind-the-radiator-in-as-much-heat-as-possible-without-mounitng-it-inside-the-engine design is terrible, to say the least, and just plain stupid to be blunt. HOWEVER, although it shortens the life of the ICM, it doesn't shorten it that much. So...
1). When you replaced the ICM the first time, was it OEM AC Delco, as 'Money Pit Beretta' asked? If not, it may have failed because of quality concerns. And used is just that -I'm finally getting away from replacing used with used, just because the replacement used parts are getting older and older at this point, so it isn't always worth it.
2).'GHOSTOWLGRID' has a good point, I wasn't thinking of that one, but a shorting coil can take out an ICM.
3). Make sure you have a clean, solid ground -an intermediate ground can wreak havoc on the relatively delicate ICM.
4). If possible, have your alternator checked-out, if it is running too high a voltage, that will toast the ICM rather quickly, and transient voltage-surges are just as bad, so watch for flickering or dimming lights/other indications too.
5). I've never heard of a bad ECM taking out an ICM, but anything is possible. I still wouldn't look at replacing that without a lot more evidence, though.
6). I also relocated the ICM on my '90 turbo 'Retta, when it was a 3.1 LG5 (now a 3.4 in LG5 clothes), and the ground was the only wire I had to cut, but be careful how you re-run the Crank Position Sensor wires (the twisted yellow and purple pair from the back of the block) to make sure they stay off of exhaust parts and driveline areas, particularly if you have a manual trans. Behind the right (passenger-side) strut tower is a great place for the ICM/coil-pack, even cooler than the 3100 rear-mount design.

Good luck, keep us posted about what you find, you are not the only one with similar problems, so you could help guide the rest of us, too.

[Beretta1234567]

The under-the-manifold-behind-the-radiator-in-as-much-heat-as-possible-without-mounitng-it-inside-the-engine design is terrible, to say the least, and just plain stupid to be blunt. HOWEVER, although it shortens the life of the ICM, it doesn't shorten it that much. So...
1). When you replaced the ICM the first time, was it OEM AC Delco, as 'Money Pit Beretta' asked? If not, it may have failed because of quality concerns. And used is just that -I'm finally getting away from replacing used with used, just because the replacement used parts are getting older and older at this point, so it isn't always worth it.
2).'GHOSTOWLGRID' has a good point, I wasn't thinking of that one, but a shorting coil can take out an ICM.
3). Make sure you have a clean, solid ground -an intermediate ground can wreak havoc on the relatively delicate ICM.
4). If possible, have your alternator checked-out, if it is running too high a voltage, that will toast the ICM rather quickly, and transient voltage-surges are just as bad, so watch for flickering or dimming lights/other indications too.
5). I've never heard of a bad ECM taking out an ICM, but anything is possible. I still wouldn't look at replacing that without a lot more evidence, though.
6). I also relocated the ICM on my '90 turbo 'Retta, when it was a 3.1 LG5 (now a 3.4 in LG5 clothes), and the ground was the only wire I had to cut, but be careful how you re-run the Crank Position Sensor wires (the twisted yellow and purple pair from the back of the block) to make sure they stay off of exhaust parts and driveline areas, particularly if you have a manual trans. Behind the right (passenger-side) strut tower is a great place for the ICM/coil-pack, even cooler than the 3100 rear-mount design.

Good luck, keep us posted about what you find, you are not the only one with similar problems, so you could help guide the rest of us, too.

Do you really get that much more life out of moving it from the base of the block, or do you notice it lasting longer?
I ask because with me, everything always seems to be backwards from what I read on the forums:
My 96 Beretta with the 3100 SFI it broke around 115,000 miles; And my 90 Beretta with the 3.1L MPFI it still lives. And I let it idle a lot; almost as much as I drive it. And over 200,000 miles later i can say: "IT LIVES!"
(In a Dr. Frankenstein voice. lol)

[3X00-Modified]

I guess it depends on the quantity in your sample... you had one of each... That's not very fair for odds; and if you look at a widespread collection of vehicles ICM/Coil failure is higher on 2.8/3.1 models.

[Rettax3]

Do you really get that much more life out of moving it from the base of the block, or do you notice it lasting longer?
I ask because with me, everything always seems to be backwards from what I read on the forums:
My 96 Beretta with the 3100 SFI it broke around 115,000 miles; And my 90 Beretta with the 3.1L MPFI it still lives. And I let it idle a lot; almost as much as I drive it. And over 200,000 miles later i can say: "IT LIVES!"
(In a Dr. Frankenstein voice. lol)

The 2.4 Twin Cam (modified and turbo-charged) in my '97 Cavalier lost the ICM, and I had some issues with the '92 Pontiac Grand Am Quad I had back in the day. The Twin Cam/Quad engine family probably found the only place on an engine that might be worse than the 2.8/3.1 V-6 engines' mounting location. The 3x00 family still places its' ICM in a particularly warm part of the engine-bay, and GM could have done better than this without trying very hard, though it is still much improved over the MPFI engines.
As for your question, honestly, I don't recall the ICMs going out on ANY of my V-6 cars for sure, although I think my '90 turbo 'Retta might have gone out many years ago, before the relocation... All I can say for certain is that I felt a need to pull a spare out of the junk-yard over a decade ago, and I still have it.
I have, however, replaced numerous bad ICMs over the years (on other peoples' cars), from the V-6s and Quads alike, and yes, the 2.8s and 3.1s are older and therefore their parts are older than the 3x00 engines, but in my experience, they tend to have a lower life expectancy the closer they are to the engine's heat, and that makes sense to me. Electronics don't like heat. That said, if yours ain't broken, why fix it?