ICM issues, need help

Mass ownage · Post by **Mass ownage** » Wed Jul 11, 2012 7:48 am

My 85 Waggie V8 keeps eatting icm's like they are candy. Gone through 3 in a couple weeks. The last one lasted a week. Is there a common cause for this? I did a search and didn't find anything. Last week I did the TFI mod and it ran great for a week, smooth idle, no issues. Then in the drive-throu this morning it just died, no spark. Swapped out the icm and back running smooth.

Post by **Stuka** » Wed Jul 11, 2012 11:28 am

Mass ownage wrote:My 85 Waggie V8 keeps eatting icm's like they are candy. Gone through 3 in a couple weeks. The last one lasted a week. Is there a common cause for this? I did a search and didn't find anything. Last week I did the TFI mod and it ran great for a week, smooth idle, no issues. Then in the drive-throu this morning it just died, no spark. Swapped out the icm and back running smooth.

Check your grounds. It's also posible the issue is not with the ICM, but is actually your magnetic pickup in your distributer.

Did you have the "failed" ICM tested by you parts house to see if it was actually bad?

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Mass ownage · Post by **Mass ownage** » Wed Jul 11, 2012 1:32 pm

Not yet, doing that after work.

Mass ownage · Post by **Mass ownage** » Thu Jul 12, 2012 4:55 am

ICM was bad, warrantied it out and picked up a new distributor since the old one was under warranty. Not sure if this will fix the issue. Is there a fuse for the icm. I know the fuse box has a fuse for ign, wasn't sure if that went to the icm or
not. Someone had a 25 in it instead of a 15. I swapped it with a 15 last night.

Post by **Stuka** » Thu Jul 12, 2012 7:10 am

Be sure to check your grounds while you are replacing things.

I think that ignition fuse is for the ICM/coil, but recall witching pulling out a TSM, which is back at home currently.

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Mass ownage · Post by **Mass ownage** » Fri Jul 13, 2012 10:20 am

Thanks gonna check and clean all the grounds this weekend. So far so good.

Mass ownage · Post by **Mass ownage** » Fri Jul 13, 2012 5:03 pm

Added a ground wired after I killed another ICM. What is the white wire on the ICM for, it connects to the lblue wire on the harness? But the jeep starts and runs without it...

adzam · Post by **adzam** » Fri Jul 13, 2012 6:34 pm

I've gone through 2 ICMs in the last 8 months (which seems to be a little better than what you are going through)

I might take a look at my grounds too, although I think mine was due to a bad ignition switch, which I as leaving ON occasionally to listen to the radio when working on the interior because the ACC position didn't work. Well, that and the really hot weather.

Is there a list of all the ground connections someplace??

Mass ownage · Post by **Mass ownage** » Sun Jul 15, 2012 3:37 pm

I'm getting 14 volts to the ICM power wire, is this correct or do I need to install a resistor?

Post by **Stuka** » Sun Jul 15, 2012 4:07 pm

Thats right as far as I know. It should be running on the main 12V line without any voltage drops. Your alternator should put out around 14-14.5, so sounds right.

Mass ownage · Post by **Mass ownage** » Sun Jul 15, 2012 4:31 pm

Yeah it's about 14.4

Mass ownage · Post by **Mass ownage** » Thu Jul 26, 2012 4:10 pm

Adzam, I piggy-backed a ground wire from the distributor ground wire that goes to the icm to the battery ground, and I haven't had any problems since. Now that I've said that it will probably die on the way home, but so far so good.
Only thing I need to get working is the cruise now.

Post by **Stuka** » Thu Jul 26, 2012 5:27 pm

Well, its a start

Hope it stays working for you.

Mass ownage · Post by **Mass ownage** » Fri Jul 27, 2012 10:33 am

Killed on me today in the drive thru. I noticed everytime it happens I'm idling at a long red light or in a drive thru. Is it possible the heat is killing them?

Post by **Stuka** » Fri Jul 27, 2012 10:43 am

Not impossible. I take it when this happens, the ICM is dead dead, it does start working again after it cools down or anything like that?

May be worth checking the voltage going too it. It should be the normal rail voltage (14-14.5 when engine is running). But maybe your regular is failing causing that voltage to be higher? Or maybe there are some bare wires someplace that cause a short. Kind of just throwing ideas out there. As you should not be going through modules this fast :/

Mass ownage · Post by **Mass ownage** » Fri Jul 27, 2012 10:47 am

When it dies, it usually starts back up for a second, then it's dead dead. I've also change Alternators since this started happening, thinking the regulator in the old one was bad.

Mass ownage · Post by **Mass ownage** » Fri Jul 27, 2012 10:52 am

I've gone through all the wires in the engine bay and replaced anything that looked bad (the PO had a bunch of butt slices in the wiring that I took care of the proper way)

Mass ownage · Post by **Mass ownage** » Fri Jul 27, 2012 7:56 pm

Was talking to brother about this, and we remembered that last year I had a problem my jeep randomly dying, but it would start right back up. Ended up being the starter solenoid. We're wondering if it's happening again, resulting in voltage spikes. But nothing else is burning out.... The quest continues....

Post by **Stuka** » Fri Jul 27, 2012 8:16 pm

Mass ownage wrote:Was talking to brother about this, and we remembered that last year I had a problem my jeep randomly dying, but it would start right back up. Ended up being the starter solenoid. We're wondering if it's happening again, resulting in voltage spikes. But nothing else is burning out.... The quest continues....

The starter solenoid wouldn't cause voltage spikes. It may cause the voltage to drop (high internal resistance), but not go up.

My first thought when you described your issue was that your magnetic pickup coil in the distributer was going out. When they get hot, they stop working. Let them sit for a bit, and bam they work again. But if your ICM is testing bad by the parts house, then thats most likely not your issue.

Mass ownage · Post by **Mass ownage** » Sat Jul 28, 2012 8:03 am

Yeah I thought about the pickup too, so I changed it a couple weeks ago.... Installing a volt meter today or tomorrow so I can try to watch for high voltage.

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