Mississippi-Mud Forums

I am having problems with the ignition system in my 1990 model Isuzu Trooper with a GM 2.8L v6 265,000 miles.
On Christmas Day the the truck stopped firing while going down the road. I had a gut feeling that the ignition module had gone bad so I replaced it the next day and was back on the road again. At least for a couple or three weeks until I was going down the road about a half mile from my house when my Trooper instantly started running like crap. I knew that if I stopped the truck that it wouldn't start again. I was able to make it to the house. The truck would barely run, had no power and was backfiring. After it quit I could not get it started again. I figured it was the ignition module again, but I had it tested and it passed using two different analyzers. Then I figured that the timing chain had jumped time and when I tested the the play it had nearly 10deg of play, so I replaced the timing chain. After replacing the timing chain the Trooper would start and run for about 5 - 10 minutes and then start backfiring and wouldn't start until it cooled down. Tonight I went and had the ignition module tested again. This time it failed, so they replaced it. After installing the new module the engine ran fair. I let it idle for about 15 minutes and started down the street. Within a couple of blocks the engine stopped cold - now the third ignition module gone.

I am out of ideas here. Does anyone have any ideas as to why the ignition modules keep burning up?

Any help is appreciated.

Thanks

check the power to the module, something has to keep causing modules to go bad. also check the temp switch. are you having any other signs? can you pull codes from the ECU?

Could it be a faulty coil? I had one that used to overheat and quit, then cool down and run fine.

X2 on checking the supply voltage and ground.

Either there is something wrong with what feeds the module or someting wrong with what the module feeds.

Check to see if any wires are grounding out, or see if the insulation is nicked or scraped off. Have you installed an aftermarket tach? If so unhook it. I have see them go bad and cause ignition problems.

sounds like to me the coil is heating up and breaking down.. I've had that happen to me a few times in the past

I had a Dodge Raider that I had removed the ballast resistor on the coild and the coil was frying the Ign module. So if you are supposed to have a ballast and don't, it will burn out modules repeatedly. If it doesn't then I'm with everyone else, Coil.

Thanks for all the replies.
Based on all the replies it sounds like a grounding problem or the coil. I had our monthly FD training last night so I wasn't able to get to do any work on the Trooper. I need to find a diagram and specifications for the wires going to the ignition module so I can verify those readings. The Haynes manual I have has little to no information on the v6 ignition, they limit almost all information to the 4cyl ignition. I will try to do some work after church tonight, and report the results.

Again, thanks for all the help.

Get a Chilton's manual. I think they have better information than the Hayne's. Just my .02.

I would suggest getting both one usually has more than the other, So i just opted to get both. It never hurts

I buy my manuals dirt cheap through CAMPUSi book search site.