96bulldogpower Posted Friday at 02:22 PM Share Posted Friday at 02:22 PM Hey guys I have an issue with our main problem child again. Truck is a 12’ granite mp7. A bit of history, we got the truck with a burned ecm when we bought it, we replaced the ecm with a used one and it ran for a while, we started having issues with emissions components so we had it deleted about 3 months ago. Then truck ran great for 2 months then the ecm failed again this time it still started but only ran on three cylinders. We replaced the ecm yet again with a used one and had it deleted again and the truck ran great for 2 weeks. Today, we started the truck in the morning and it ran for 10 seconds then shut off, now if you try to start it only the dash lights up like usual but the engine doesn’t crank or start. I did the preliminary things like checking fuses and battery connections (new batteries three days ago), but nothing seems out of order. I’m having someone bring me my laptop later today to hook up and see what’s going on, but I’m already suspecting bad ecm again. Do you guys have any insight? What can be causing this truck to repeatedly burn ecm’s? Any tips on dealing with the no start no crank if it isn’t the ecm? It did start initially for 10 seconds before going dead. Quote Link to comment https://www.bigmacktrucks.com/topic/76364-another-mp7-no-crank-no-start-with-history-of-burned-ecm%E2%80%99s/ Share on other sites More sharing options...
96bulldogpower Posted Friday at 04:05 PM Author Share Posted Friday at 04:05 PM Well guys I got it hooked up and it’s not looking good. No hours on the hour meter and it has communication codes. This is classic of yet another burned ecm. Does anyone know why this truck keeps burning out ECM’s? ill do some more diagnostic on it later today when I have time just to rule out other variables, but im pretty certain its got a bad module. Quote Link to comment https://www.bigmacktrucks.com/topic/76364-another-mp7-no-crank-no-start-with-history-of-burned-ecm%E2%80%99s/#findComment-590363 Share on other sites More sharing options...
880joe Posted Friday at 06:12 PM Share Posted Friday at 06:12 PM Any chance you might have antifreeze or oil wicking into the ECM? That was an issue on the E7'S some times 1 Quote Link to comment https://www.bigmacktrucks.com/topic/76364-another-mp7-no-crank-no-start-with-history-of-burned-ecm%E2%80%99s/#findComment-590378 Share on other sites More sharing options...
96bulldogpower Posted Friday at 06:20 PM Author Share Posted Friday at 06:20 PM 4 minutes ago, 880joe said: Any chance you might have antifreeze or oil wicking into the ECM? That was an issue on the E7'S some times Ecm plugs are completely dry, I did injectors on this truck not that long ago and I saw oil in the connectors for each injector so I figured it was on borrowed time for a new engine harness, but no there’s no oil or coolant that has made it yet to the ecm connectors. Quote Link to comment https://www.bigmacktrucks.com/topic/76364-another-mp7-no-crank-no-start-with-history-of-burned-ecm%E2%80%99s/#findComment-590379 Share on other sites More sharing options...
Geoff Weeks Posted Friday at 06:20 PM Share Posted Friday at 06:20 PM repeated bad ECM's with comm codes would have me looking at the wiring harness also. My guess is something is cross shorting and frying communication. Going to be hard to find. 1 Quote Link to comment https://www.bigmacktrucks.com/topic/76364-another-mp7-no-crank-no-start-with-history-of-burned-ecm%E2%80%99s/#findComment-590380 Share on other sites More sharing options...
Joey Mack Posted Friday at 06:56 PM Share Posted Friday at 06:56 PM I guess he needs to unplug the E.C.U.'s and check for continuity on every pin to every other pin in each plug end. when he finds continuity, then he finds the 'short' This is tedious, but so is paying thousands to buy ECU's only to cook them. Im seein the Vehicle module and I think the injection control module are faulting. What is the ICM, again, I forgot. 2 Quote Link to comment https://www.bigmacktrucks.com/topic/76364-another-mp7-no-crank-no-start-with-history-of-burned-ecm%E2%80%99s/#findComment-590381 Share on other sites More sharing options...
fjh Posted Friday at 07:36 PM Share Posted Friday at 07:36 PM It’s not uncommon for bad wiring under the valve cover will shut down cylinders and werid stuff goes on! A place to look! just sayin 2 Quote Link to comment https://www.bigmacktrucks.com/topic/76364-another-mp7-no-crank-no-start-with-history-of-burned-ecm%E2%80%99s/#findComment-590384 Share on other sites More sharing options...
96bulldogpower Posted Friday at 08:50 PM Author Share Posted Friday at 08:50 PM I agree that it could be wiring related, I spent some more time with the truck trying to figure out what’s going on. The engine ecm is definitely offline, it won’t communicate with the laptop. Power and ground leading up to it seem fine from what I could test with what tools I had available to me. As much as I hate to “parts cannon” a truck, I think I’m going to try replacing the engine harness. It still needs an ecm though from what I can tell. I already took the ecm off, I’ll have it tested and repaired tomorrow if all goes well. Could someone please get the the correct part number for the engine harness for the truck? 2012 GU713 MP7 VIN: 1M2AX04C5CM011802 1 Quote Link to comment https://www.bigmacktrucks.com/topic/76364-another-mp7-no-crank-no-start-with-history-of-burned-ecm%E2%80%99s/#findComment-590388 Share on other sites More sharing options...
Geoff Weeks Posted Friday at 09:28 PM Share Posted Friday at 09:28 PM (edited) This is a little out of my experience, however I know someone who posts on a different board, He repairs "lightening strike" vehicles. One thing I picked up from him, that one bad module can pull the whole Canbus down giving the impression that everything is "dead". Once the one the one thing that is killing communication on the bus is disconnected the rest can come back to life. This requires locating where they are tied to the canbus wiring and removing one by one, until the bad one is found, re connecting one by one to make sure you don't have more than one. He also says to check the resistance between the hi and lo buss wires and look for a set resistance (150 ohm?) I'm not sure about the resistance I could check with him if you get that far. Higher is an open somewhere and lower is something on the buss is shorted. Edited Friday at 09:29 PM by Geoff Weeks 1 Quote Link to comment https://www.bigmacktrucks.com/topic/76364-another-mp7-no-crank-no-start-with-history-of-burned-ecm%E2%80%99s/#findComment-590392 Share on other sites More sharing options...
96bulldogpower Posted yesterday at 03:19 AM Author Share Posted yesterday at 03:19 AM Ok update: I remembered something just before the truck went down. The truck was frequently going into high idle around 1100rpm just randomly throughout the day anytime the parking break was set and the truck sat idling around 5 minutes. I figured it had something to do with the smart idle settings in the parameters, which cause the truck to raise the idle to maintain charging voltage when it sensed it was low. This prompted us to replace all the batteries since one was bad. Only three days before the truck went down. It was also only showing 13.2 volts at idle and the smart idle function triggers when voltage hits 12.8 volts and raises the rpm. Fast forward to this weekend, I took the ecm in for repair and they told me it was too badly burnt to repair, I still have the burnt ecm, it’s not repairable. I got another used replacement ecm and had it cloned with another that I have for this truck, got it back to the truck and installed it. I also installed an additional heavy gauge ground wire directly to the ecm because the oem ground strap that the ecm’s come with was looking pretty questionable. I got the truck started and I’m not sure, but now that it has additional grounding, the voltage on the dash now reads 13.7 volts. I don’t know if that’s coincidence or what. Anyway, the truck is set to return back to service tomorrow, I’ll update when I know how it behaves. 1 Quote Link to comment https://www.bigmacktrucks.com/topic/76364-another-mp7-no-crank-no-start-with-history-of-burned-ecm%E2%80%99s/#findComment-590496 Share on other sites More sharing options...
Joey Mack Posted 19 hours ago Share Posted 19 hours ago We used to run an extra ground for the EECU on E-Techs for similar issues.. 2 Quote Link to comment https://www.bigmacktrucks.com/topic/76364-another-mp7-no-crank-no-start-with-history-of-burned-ecm%E2%80%99s/#findComment-590499 Share on other sites More sharing options...
Popular Post 70mackMB Posted 13 hours ago Popular Post Share Posted 13 hours ago Those DAMN grounding issues, get you every time. .....Hippy 3 2 Quote Link to comment https://www.bigmacktrucks.com/topic/76364-another-mp7-no-crank-no-start-with-history-of-burned-ecm%E2%80%99s/#findComment-590510 Share on other sites More sharing options...
Popular Post Joey Mack Posted 11 hours ago Popular Post Share Posted 11 hours ago Its the Damned computers... and the grounds too... 😁 2 1 Quote Link to comment https://www.bigmacktrucks.com/topic/76364-another-mp7-no-crank-no-start-with-history-of-burned-ecm%E2%80%99s/#findComment-590518 Share on other sites More sharing options...
Popular Post The Heinz Posted 11 hours ago Popular Post Share Posted 11 hours ago I sent him the part number for his harness via PM, but I figured I'd put the part number for the oil wicking kit in public view in case anyone needs it. The part number is 85137983, available from your local dealer. Comes with everything needed to prevent the harness from wicking oil. 4 1 Quote Link to comment https://www.bigmacktrucks.com/topic/76364-another-mp7-no-crank-no-start-with-history-of-burned-ecm%E2%80%99s/#findComment-590519 Share on other sites More sharing options...
Geoff Weeks Posted 10 hours ago Share Posted 10 hours ago Kinda sounds like it was "finding ground" through the ECM circuits? 2 Quote Link to comment https://www.bigmacktrucks.com/topic/76364-another-mp7-no-crank-no-start-with-history-of-burned-ecm%E2%80%99s/#findComment-590522 Share on other sites More sharing options...
Joey Mack Posted 9 hours ago Share Posted 9 hours ago I have a question... Did you or anyone bypass the fuel lines going to the cooling plate on the EECU ? 1 Quote Link to comment https://www.bigmacktrucks.com/topic/76364-another-mp7-no-crank-no-start-with-history-of-burned-ecm%E2%80%99s/#findComment-590526 Share on other sites More sharing options...
96bulldogpower Posted 2 hours ago Author Share Posted 2 hours ago 8 hours ago, Geoff Weeks said: Kinda sounds like it was "finding ground" through the ECM circuits? I agree. I think that as these things age, the factory installed ground strap starts to lose connection until the ecm eventually burns itself from trying to find ground through other circuits. Just a theory though, I wish I knew for sure. 1 Quote Link to comment https://www.bigmacktrucks.com/topic/76364-another-mp7-no-crank-no-start-with-history-of-burned-ecm%E2%80%99s/#findComment-590554 Share on other sites More sharing options...
96bulldogpower Posted 2 hours ago Author Share Posted 2 hours ago 7 hours ago, Joey Mack said: I have a question... Did you or anyone bypass the fuel lines going to the cooling plate on the EECU ? Not sir, the fuel lines are still routed to the cooling plate like it came from the factory. Looks like this will end up being an electrical issue from what I’m gathering Quote Link to comment https://www.bigmacktrucks.com/topic/76364-another-mp7-no-crank-no-start-with-history-of-burned-ecm%E2%80%99s/#findComment-590555 Share on other sites More sharing options...
96bulldogpower Posted 2 hours ago Author Share Posted 2 hours ago Update, truck ran all day today and functioned perfectly. I’m still concerned about the truck burning this ecm as it’s the very last one I had in my parts stash. I’m ordering a brand new one tomorrow and I’ll have the ecm shop clone it again. Heinz provided me a part number for the whole engine wiring harness. My plan is to install the new harness and new ecm at the same time, I will also be installing the additional ground cable directly on the Ecm body like I have it now, can’t hurt anything I guess. I’ll put an order in by tomorrow for the parts and the truck is set to come back to the shop in a couple of weeks at which point I’ll get it all installed, as long as it survives until then anyway.. 1 Quote Link to comment https://www.bigmacktrucks.com/topic/76364-another-mp7-no-crank-no-start-with-history-of-burned-ecm%E2%80%99s/#findComment-590556 Share on other sites More sharing options...
96bulldogpower Posted 2 hours ago Author Share Posted 2 hours ago Not to be a cheap azz, I usually buy only OEM especially for specialty or critical parts like these. But this truck is bleeding us dry.. Have any of yall ever tried the knock off ecm’s on eBay? They look 100% identical and another listing shows the innards and it also looks identical to a real Mack/volvo ecm with no visible differences in the circuitry. Any reason why this wouldn’t work? I got quoted $3900 for an oem ecm blank.. trying to save some money if at all possible. Quote Link to comment https://www.bigmacktrucks.com/topic/76364-another-mp7-no-crank-no-start-with-history-of-burned-ecm%E2%80%99s/#findComment-590557 Share on other sites More sharing options...
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