nolant Posted April 4, 2017 Share Posted April 4, 2017 truck was berly running when i got to it i put my computer on it and was calling out #1&3 injectors cleared the code and it cleared up sounded good for about 5 min then right back to same codes. got it hooked back to the shop replaced those 2 injectors started it same problem so i figured engine harness the plugs looked pretty bad and were brittle well replaced it same problem. last thing i could think of ecm right swapped it with one we had off another truck that was running fine still same issue. im lost on this one. Quote Link to comment https://www.bigmacktrucks.com/topic/49395-2007-mack-mp7-injector-issue/ Share on other sites More sharing options...
Mackpro Posted April 4, 2017 Share Posted April 4, 2017 You know that the actual fault code was SID number and FMI number? Quote Link to comment https://www.bigmacktrucks.com/topic/49395-2007-mack-mp7-injector-issue/#findComment-366384 Share on other sites More sharing options...
nolant Posted April 5, 2017 Author Share Posted April 5, 2017 It was sid 3 fmi 5 Quote Link to comment https://www.bigmacktrucks.com/topic/49395-2007-mack-mp7-injector-issue/#findComment-366430 Share on other sites More sharing options...
Mackpro Posted April 5, 2017 Share Posted April 5, 2017 Heres what we see on most all FMI 5 injector faults injector Harness end connectors.pdf Quote Link to comment https://www.bigmacktrucks.com/topic/49395-2007-mack-mp7-injector-issue/#findComment-366439 Share on other sites More sharing options...
nolant Posted April 5, 2017 Author Share Posted April 5, 2017 ok i understand that but wouldnt a new harness from mack have the updated end connectors? because i already put a new harness on it. Quote Link to comment https://www.bigmacktrucks.com/topic/49395-2007-mack-mp7-injector-issue/#findComment-366447 Share on other sites More sharing options...
Keffer inc Posted April 5, 2017 Share Posted April 5, 2017 Fuel preasure good? Quote Link to comment https://www.bigmacktrucks.com/topic/49395-2007-mack-mp7-injector-issue/#findComment-366486 Share on other sites More sharing options...
nolant Posted April 6, 2017 Author Share Posted April 6, 2017 My computer is showing 95 Quote Link to comment https://www.bigmacktrucks.com/topic/49395-2007-mack-mp7-injector-issue/#findComment-366545 Share on other sites More sharing options...
Mackpro Posted April 6, 2017 Share Posted April 6, 2017 Sounds like you replaced everything. We had some FMI 7 injector codes due to engine brake pungers sticking. I'm still looking Quote Link to comment https://www.bigmacktrucks.com/topic/49395-2007-mack-mp7-injector-issue/#findComment-366581 Share on other sites More sharing options...
nolant Posted April 6, 2017 Author Share Posted April 6, 2017 thats what i thought..this one does not have engine brake. Quote Link to comment https://www.bigmacktrucks.com/topic/49395-2007-mack-mp7-injector-issue/#findComment-366587 Share on other sites More sharing options...
Challenger Posted April 10, 2017 Share Posted April 10, 2017 (edited) 1,2,3 injectors are on one bank. 4,5,6 are another bank. Maybe #2 shorted out 1 and 3. Switch 2 with 4,5,6 and see if the problem follows the injector. Edited April 10, 2017 by Challenger grammer Quote Link to comment https://www.bigmacktrucks.com/topic/49395-2007-mack-mp7-injector-issue/#findComment-366892 Share on other sites More sharing options...
Challenger Posted April 10, 2017 Share Posted April 10, 2017 (edited) Unrelated but your fuel pressure seems high. Is it at 95 at idle or running? Few years back I was working on a MP7 with low power. No codes everything looked ok. The fuel pressure was 95 at idle and over a 100 when running. I remember thinking, the more the better. Turned out someone put the fuel regulator at the back of the head instead of the front of the head. Switched them around and truck ran normal and fuel pressure dropped. Like I said unrelated but maybe useful info in the future. Edited April 10, 2017 by Challenger grammer 1 Quote Link to comment https://www.bigmacktrucks.com/topic/49395-2007-mack-mp7-injector-issue/#findComment-366894 Share on other sites More sharing options...
Challenger Posted April 10, 2017 Share Posted April 10, 2017 (edited) 51 minutes ago, Challenger said: 1,2,3 injectors are on one bank. 4,5,6 are another bank. Maybe #2 shorted out 1 and 3. Switch 2 with 4,5,6 and see if the problem follows the injector. To add more info. #2 could be the problem. It could be shorted and causing a problem which is knocking out injectors 1 and 3 which are on the same bank. Which would mean 1 and 3 injectors are fine and #2 was/is the problem the entire time. Try unplugging #2 and running the engine at idle. Disconnecting the injector will remove it from the bank. If the codes switches to only 2, its probably the problem. This might work and be a lot less time wasted then switching injectors around. Edited April 10, 2017 by Challenger Quote Link to comment https://www.bigmacktrucks.com/topic/49395-2007-mack-mp7-injector-issue/#findComment-366901 Share on other sites More sharing options...
nolant Posted April 11, 2017 Author Share Posted April 11, 2017 Thank y'all for all the help ended up being #2 injector I would have never thought it to be that. Quote Link to comment https://www.bigmacktrucks.com/topic/49395-2007-mack-mp7-injector-issue/#findComment-367041 Share on other sites More sharing options...
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