LB7: Engine injectors losing electrical power.

hotrod-z28

New member
Mar 17, 2015
3
0
0
Florrissant
Here's the thing, it does it randomly cold or hot, idling or running down the road. The injectors 2,4,6,7 are losing power and also getting a p2146 code. While trying to check it out I unplugged the lower main harness plug while it was running, course it died, then plugged it back in and proceeded to clear codes. Starts back up and runs fine for a short time or doesn't do it again until the next trip. I keep my scanner in the truck just in case. While checking it again I found a wire on the upper plug that was broken, so I fixed it, from what I can tell it is the wire going to the boost sensor. Upon trying to start it after fixing the wire, it would not turn over, checking fuses it had blown the ECM fuse, replaced it and it blew again, I cut that wire I had just fixed and replaced the fuse and it started.
Question: is the two related or two separate issues, I've been researching this from the internet to repair manuals and have come here hoping someone might of had the same or similar issues. The truck has 255,000 miles on it but engine still runs like when I bought at 40,000.
Any suggestions and help would be greatly appreciated. '03 LB7
 
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2004LB7

Well-known member
Dec 15, 2010
2,656
26
48
Norcal
Did the injectors get replaced not long ago, like 10k mikes or so? Maybe one of the injector harness fasteners has come loose. Not too uncommon if not torqued right
 

TheBac

Why do I keep doing this?
Staff member
Apr 19, 2008
13,375
21
38
Mid Michigan
Moved to LB7 section. FICM wiring rub-thru by the mounting bracket would be my guess, but then it could be loose connections if the injectors had just been replaced, too.
 

hotrod-z28

New member
Mar 17, 2015
3
0
0
Florrissant
I changed the injectors at 216,000, I have 255,000 now. I went ahead and took apart all of the plugs and cleaned them, including the FICM plugs. I also check the grounds, so we'll see if that does it
 
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KyleC4

Tech
Dec 30, 2016
334
6
18
Bay Area
So I take it you fixed the MAP sensor wire that was rubber through and grounding out? You said you kept blowing the ECM fuse so you cut the wire you just fixed.....so is it fixed now or just cut? A grounded circuit is not good. May want to follow that and figure where it’s shorted to ground that’s causing that fuse to blow consistently unless you have then ignore what I said.
 

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