Pressure gauge installed. Pressure is solid during entire range of operation. Ran truck from a bucket of fuel looking for any air bubbles on the return line or performance changes. All stays the same, slight miss. Now I'm getting insite messages that the "ecm detects conditions in which the cylinder cut out test should not be run"
It's looking like ecm related. Not sure what else to test/check
Cummins n14 injector issue
Discussion in 'Heavy Duty Diesel Truck Mechanics Forum' started by Kenllah, Feb 1, 2021.
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What was your range of fuel pressure?
Kenllah Thanks this. -
Appx
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Did some more testing with insite and a fuel pressure gauge.
Fuel pressure bouncing from 120 psi to 130psi at 900rpm pto speed
Appx 135 +- 2psi @ 1091rpm
126psi at idle +-1psi
Initiate cylinder cutout test
135psi +-3psi rough idle no #4 injector response
Accelerator based cut out all cylinders 85-89 rpm difference EXCEPT #4 at only 11RPM difference.
125psi @ idle after test slight miss no smoke unplug #4 injector and she stumbles -
As a follow up I ended up sending the ecm off for testing to DSO Industrial. Exceptional service and very fast. Injector drivers in the ecm was my problem. I have all the tech manuals for this engine as well as cummins insite. It is kind of difficult because of the possibility of bad reman injectors. You can waste a lot of time and money playing swap the injector. I even hooked my injectors up to an oscilloscope to watch the waveform and they all looked good. I guess the timing from the drivers was just off a bit. There was also a ticking in the overhead that I could never get to stop no matter what I tried. That has also gone away with the new ecm.
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