Possibly bad injector? Opinions Please!
Just got back from a very long trip towing a 7K travel trailer from Albuquerque NM down to Ft. Lauderdale Fl and back.
This was my first opportunity to run the Duramax for the long haul with some weight behind it. Anyway, when I started out I was gettiing about 12mpg at
75mph. I thought this was great but after about 500 miles the following occurred, The truck went into regen and completed successfully, the fuel economy dropped during the regen (expected). I stopped for fuel and reset all the mileage in the dic. I started back out but my mileage was averaging about 9.5 and at one point was down as bad as in the high 7.
I have an edge monitor so I know the truck was not in regen so I thought I would check the injector balance to see if it might shed some light on the poor fuel economy. I took 2 samples about 5 minutes apart, these were at approx 70mph, fully loaded and engine at temp:
Inj 1: -3.8 -4.3
Inj 2: 2.1 2.0
Inj 3: 2.0 2.6
Inj 4: 0.5 0.6
Inj 5: -1.9 -2.0
Inj 6: 2.0 1.7
Inj 7: 0.1 0.3
Inj 8: -0.8 -0.6
You can see Injector 1 seems to be having a problem, (no 5 is not great also) watching it I have seen it go as high as -4.6, when the engine idles Injector 1 hovers around -2+. This is got me a little baffled, and if this was an LB7 instead of an LML I would be fairly confident injector 1 is bad.
The regens that took place were all normal and were triggered by mileage and not soot, about every 750 miles. The other thing I noticed is the engine seems a little noisier since this trip. Perhaps it might be a result of oil breakdown from the long trip. I am considering taking it to the dealer to have this checked out but am concerned the dealer will just blow it off because no codes have been set and the truck does not seem to be blowing any soot or smoke. Also as I understand it GM wont even think about replacing an injector unless it at least Plus or Minus 4 all the time.
I would think a truck with only 32k would not have injector issues but perhaps I am missing something with this. One thing I forgot to mention is this is still running a stock tune and is not modded yet. I really need to get this sorted out before the warranty is gone. Any suggestions?
The Dark Knight: 2013 Silverado Extended Cab 2500HD LTZ, Z71, Z82, Z71 Apperance pkg, Black on Black, 20" Alloys, CTS,
Stock LML but to be deleted when the warranty is over
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