International 8100 with M11 - Electrical Nightmares, need guidance

[thesanchez]

I have a 99 8100 with the cummins m11. We bought the truck used a year ago, drove it ten miles, ended up throwing a rod. We found a replacement block, rebuilt the motor, cranked and ran fine. Had a TPS issue. Replaced TPS and pedal assembly, still didn't work, so our mechanic made his own TPS overlay harness to see if we could eliminate maybe a broken wire and it all went down hill from there. Now the ECM (Celect Plus) isn't even responding, yet we've ohmed out the whole OEM harness. We've tried a rebuilt ECM from the dealer (UGH!), new engine harness (besides the OEM harness because we can't seem to find that). Now the truck is popping a fuse when you hit the ignition for the Kysor/Coolant level. I've checked the particular circuit and can't seem to find any problems, it ohm's out fine, but I'm guessing there's a issue with the harness inside the cab.

Does anyone have any ideas where to start? I'm so embarrassed and frustrated, I have literally 3 months of a mechanics time in the truck, tens of thousands of dollars of worthless parts, and a truck that won't even crank over.

 

[87silvert]

Just an idea here. Disconnect the ground from batteries. Replace all blown fuses. Turn everything on including the ignition. Disconnect the plugs at the firewall. Use a multimeter to test for continuity from each pin to positive of the battery. With each one you find continuity verify that you should using a factory pinout. Do the same with each pin to ground. Every time you find continuity verify that it should be there. Don't forget to do pins on both sides of connector so you are effectively checking in cab and motor and chassis.

 

[87silvert]

oh, and I have gotten new harnesses pinned wrong because of serial number variations. So take your time. Also, is it not cranking as you said or not firing? The cranking circuit is very simple and if it won't crank that is a great place to start.

 

[thesanchez]

oh, and I have gotten new harnesses pinned wrong because of serial number variations. So take your time. Also, is it not cranking as you said or not firing? The cranking circuit is very simple and if it won't crank that is a great place to start.

Great idea! I'll go through it and see if I can find something.

 

[thesanchez]

oh, and I have gotten new harnesses pinned wrong because of serial number variations. So take your time. Also, is it not cranking as you said or not firing? The cranking circuit is very simple and if it won't crank that is a great place to start.

I guess I can't edit my previous post.

Originally the truck was cranking and starting just fine (post rebuild). We experienced a TPS issue, pulled the front half of OEM harness out and traced every wire, confirming that the pin out was correct. We re-installed the harness in the truck and now it's tripping a fuse/breaker and it won't crank over, nor is the ECM turning on (based on the check engine lights). I'm going to troubleshoot based on your suggestion today and see what I can find.