Got the ecm back yesterday and now thrle truck does not try to run right even cold. The repair shop said they found issues with the injector drivers and got them repaired but the truck must have some other rewiring issues. I plan to remove the loom from the ecm to the bail connectors and inspect for worn or broken wiring. Hopefully I can get that done today
Still having trouble, need recomendations
- Thread starter cjbennett1984
- Start date
Thanks that may very well be on the horizon. Today I am going to see if I can locate any damaged wiring from the ecm to the bail connectors. I checked them for resistance but it is difficult to do alone and move wiring around. So I will look for visual evidence. Then I might have to get another ecm. The company that repaired mine said they could not provide me with a new one so my options might be to find one in a junkyard?
Do you have to have it programmed for your truck or are they universal? What is a reasonable price
if you get one that came from the same model engine then you may only need to update the Vin to satisfy the VATs but there are ways around that too such are relearning it. if it comes from another vehicle that happens to use the same ECM then yes you'll need to have it reprogrammed
Certain vendors you can buy a used LBZ ecm off of on a Google search and pre-program it for you to your VIN if you cannot do it yourself.
I actually don't think anything needs to be programmed on a used ecm as long as you are stock
I actually don't think anything needs to be programmed on a used ecm as long as you are stock
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Wow what a colossal pita. I am pretty sure I found the culprit. After cutting the loom away and tracing down the wiring I realized the injector are twisted up into groups of three. A shared positive and the respective grounds. As I kept getting codes for 1 and 4 I suspected they were the issue. Right where the ecm harness comes out of the plug and right before it goes under the fuse block that large bundle of wires makes a 180 degree turn and was laid on top of the battery support plate. After closer inspection I found the triple group with a depression in the insulation were it sat on the edge of the plate. After flexing the wire I could see copper. It must have been shorting to the plate. The wire was not cut, only exposed. I cleaned the wire with deoxit, squeezed some silicon on it and wrapped it with electrical tape and some thermal tape. Put the ecm plugs back in and started it up. It has been run ING for about 10 min now. It revs nicely and sounds perfect. About to go to the auto store to see about some bigger loom to replace what I took/crumbled out. Thanks for all the support. Hope this is the solution I have been looking for.
yep, that'll do it. it's amazing how many have looked over the harness, ohmed it out, etc and said it all good. only to later find out it was the harness all along and could have saved a bunch of time 3 money if they'd just listened to the advice of people who've been there.
glad you found it, documented it and shared it here for others to see, and got it repaired.
glad you found it, documented it and shared it here for others to see, and got it repaired.
Well at 250k my injectors were due. I replaced the engine harness at 750$. The short could have been anywhere luckily I found where it was. So much money and hours looking for issues. Simple little nick in the wire to ground. Monday morning g quarterbacking is always easy when you know what the problem is. It's the hours and hours looking for it that are difficult. In any case I am very grateful for all the support I am looming the wire that was stripped out and putting g the tire back on but I feel pretty confident. Thanks for all the suggestions including the support I got here locally. I am ready for a break.
Glad you got it nailed, and thanks for reporting back on what the resolution was. 
Thinking back to post #28 where you said one time the problem started right when you latched the hood, and Ron's musings about this being a really good clue. It all makes sense now, how there would be a sensitivity to vibration.
Thinking back to post #28 where you said one time the problem started right when you latched the hood, and Ron's musings about this being a really good clue. It all makes sense now, how there would be a sensitivity to vibration.
Yes, I was in denial at that time. I didn't want to have to trace down the wiring, it seemed daunting. I feel I just got lucky to find the spot. It was quite difficult to get to even after cutting away the loom ad electrical tape. And that the ecm company seemed to keep finding issues with the ecm which evidently had nothing to do with the real problem. Atleast they didn't charge me for taking another look and making the existing repairs even though they may not have done anything. Hard to say. Anyway I am very grateful for the expertise that helped get me through this.
When I started today, started the truck up and it seemed to run good. I wiggled the ecm loom near the battery and the truck rattled and ran poorly. So I felt confident the issue was there close. Lucky it didn't take long to find it.
When I started today, started the truck up and it seemed to run good. I wiggled the ecm loom near the battery and the truck rattled and ran poorly. So I felt confident the issue was there close. Lucky it didn't take long to find it.
And now I will check all my harnesses. Preventively thickening the loom where it contacts metal.