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There,wolf...There,castle
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Discussion Starter #1
Have read some threads that seem similar to my issue but none seem exactly so for what it's worth throwing this out there to see if anyone has any ideas, has seen this before and in the end posting the exactly problem and fix once found.

As much of a backstory as I think may be relevant:
Saturday night filled the truck up with roughly 18 gals of fuel and drove home. Next morning got up drove the truck to church about 30 mins from the house. After church went out to crank the truck. It immediately began to lope and surge. Saw an engine overheat pop up on the DIC so shut it down. Popped the hood and checked coolant although I knew there was no way for it to have overheated. Everything looked fine. Went to try and crank it and nothing. Lights came on, lift pump was running and everything seemed to be like it should but would not even try to turn over. Began looking at fuses and found 25 amp #1 blown. Replaced that one and tried to fire again. This time it turned over but immediately shut down. Tried a couple times and it turned over each time but shut down immediately. Finally got it to stay on but it loped and surged like the first time. I couldn't spot anything obvious when looking at wires and such so had it towed to the shop. Anyway anyone got any ideas?
 

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2006 LBZ CCSB Leveled, Hypertech Programmer, 2008 LMM WT, 2008 Gasser WT
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My LMM did something similar due to a bad battery cable terminal. I fixed the terminals and tried to start. It started after about twice the normal cranking time and then died. It did this 2 or 3 times. I cleared all the codes and tried again, same thing. I cleared the codes again (don't remember what they were) disconnected both batteries for about 10 minutes and tried again. Started right up and has been fine since.
 

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LHN...We ARE the Joneses
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26,264 Posts
Sounds like a variety of probables;
Low amps can do strange things to all of the modules. Batteries should be load tested. Connections inspected.

Stud #1 fuse....feeds the 12v hot aux feed in your 7-pin trailer plug.

There are numerous idiot proof things in the logic to prevent devastation. One of those is the overheat shutdown. That info input would come from your ECT sensor, on top near the T-stats. Bad sensor, damaged wires to it, etc.

But again, back to the low amps thing. There's a lot of handshakes going on between the different sensors and modules at start up. low amps can cause conflicting info between them all.
 

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There,wolf...There,castle
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1,456 Posts
Discussion Starter #4
My LMM did something similar due to a bad battery cable terminal. I fixed the terminals and tried to start. It started after about twice the normal cranking time and then died. It did this 2 or 3 times. I cleared all the codes and tried again, same thing. I cleared the codes again (don't remember what they were) disconnected both batteries for about 10 minutes and tried again. Started right up and has been fine since.
No such luck there. Those connections look just fine and I pulled both negatives and let them sit for roughly 7 hours before reconnecting with the same results. Plus I couldn't pull any codes with the CTS or Autocal, so maybe a tech 2 can.

Sounds like a variety of probables;
Low amps can do strange things to all of the modules. Batteries should be load tested. Connections inspected.

Stud #1 fuse....feeds the 12v hot aux feed in your 7-pin trailer plug.

There are numerous idiot proof things in the logic to prevent devastation. One of those is the overheat shutdown. That info input would come from your ECT sensor, on top near the T-stats. Bad sensor, damaged wires to it, etc.

But again, back to the low amps thing. There's a lot of handshakes going on between the different sensors and modules at start up. low amps can cause conflicting info between them all.
Interesting. I just put a class V hitch on and installed a new plug and play 7 pin connector. Maybe it has something to do with it but that was 3-4 weeks ago.

As for the rest It's somewhere to start
 

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Premium Member
2006 LBZ CCSB Leveled, Hypertech Programmer, 2008 LMM WT, 2008 Gasser WT
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207 Posts
Sounds like a variety of probables;
Low amps can do strange things to all of the modules. Batteries should be load tested. Connections inspected.

Stud #1 fuse....feeds the 12v hot aux feed in your 7-pin trailer plug.

There are numerous idiot proof things in the logic to prevent devastation. One of those is the overheat shutdown. That info input would come from your ECT sensor, on top near the T-stats. Bad sensor, damaged wires to it, etc.

But again, back to the low amps thing. There's a lot of handshakes going on between the different sensors and modules at start up. low amps can cause conflicting info between them all.
Could an intermittent short, not quite dead enough to blow the fuse right away, in the trailer wiring have messed with his computer like my battery terminals?
 

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LHN...We ARE the Joneses
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26,264 Posts
Could've blown upon install.....not many check the aux12v after install, just the lights and brakes. It might not have anything to do with the truck side, might be a lose terminal inside the trailer's plug, touching another post.
 

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There,wolf...There,castle
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1,456 Posts
Discussion Starter #7
Could've blown upon install.....not many check the aux12v after install, just the lights and brakes. It might not have anything to do with the truck side, might be a lose terminal inside the trailer's plug, touching another post.
So is it coincidence that after I replaced the fuse I was able to get the truck to turn back over where prior it was nothing?
 

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There,wolf...There,castle
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1,456 Posts
Discussion Starter #8
Could've blown upon install.....not many check the aux12v after install, just the lights and brakes. It might not have anything to do with the truck side, might be a lose terminal inside the trailer's plug, touching another post.
I think we are looking at the wrong fuses. The fuse I blew was the spot one ECM fuse *1 I guess I should have said. Not stud 1
 

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There,wolf...There,castle
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1,456 Posts
Discussion Starter #9
Think the problem has been found. Can’t get the video uploaded but ecm is toast. It was pulled and has a nice jingle inside. Tried one from another truck and fired up and ran.
 

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Premium Member
2006 LBZ CCSB Leveled, Hypertech Programmer, 2008 LMM WT, 2008 Gasser WT
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I would trace the wire from that fuse plus any grounds on the circuit from one end to the other looking for a loose connection or short.
 

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2006 LBZ CCSB Leveled, Hypertech Programmer, 2008 LMM WT, 2008 Gasser WT
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You think the ECM blew the fuse? Or, whatever blew the fuse fried the ECM?
 

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There,wolf...There,castle
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1,456 Posts
Discussion Starter #12
You think the ECM blew the fuse? Or, whatever blew the fuse fried the ECM?
I imagine the ECM shorted and that spike popped the fuse. There is something rattling inside it so somethings broke off. I guess it took enough and gave up. I don't see a spike in current blew a piece off inside the ECM. But I could be wrong
 

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2006 LBZ CCSB Leveled, Hypertech Programmer, 2008 LMM WT, 2008 Gasser WT
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207 Posts
Open it up and have a look...
 

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There,wolf...There,castle
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Discussion Starter #14

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2006 LBZ CCSB Leveled, Hypertech Programmer, 2008 LMM WT, 2008 Gasser WT
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As one of my favorite Youtubers says, "It's already fucked, you can't fuck it any more"
 

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There,wolf...There,castle
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Discussion Starter #16
A few pics for anyone interested.
 

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Premium Member
2006 LBZ CCSB Leveled, Hypertech Programmer, 2008 LMM WT, 2008 Gasser WT
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207 Posts
That'll do it...
 

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There,wolf...There,castle
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1,456 Posts
Discussion Starter #19
Yup, shes pooched.
I haven't been on here much but hope your doing good! It was a sad sight to see it sitting on the back of a wrecker. Had a rookie driver and this was his biggest haul to date but probably one of the best guys I've rode with. Made it a little easier on me. Should of got a pick of that.
 

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LHN...We ARE the Joneses
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26,264 Posts
Being one to build all of my own PCs, I'm totally amazed that the ECM & TCM on these things last more than 3 months.....much less 13+ years.
 
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