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2007 mack mp7 injector issue


nolant

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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.

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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 by Challenger
grammer
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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 by Challenger
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