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2013 Chevrolet Duramax, new fuel injector #8 no difference
Truck all of a sudden vibrated, loss of some power and a lot of smoke under medium throttle. New Bosh injector and programed to the truck, no difference, checked the wire harness using a noid light and it worked fine. It coded PO308 and PO284. could a return line be the culpret? Any other thoughts? Thanks
First I would probably do a relative compression test just to quickly rule that out as a concern. But, I believe all LML's have the CP4 which are knows to cause problems. Usually if I suspect that I will pull the MPROP out and inspect if for debris. However, if the truck still has the emission equipment it isn't a super easy task. You could also cut the fuel filter open and look for debris, but I have seen trashed pumps with not debris in the filter.
I only mention the cp3 vs cp4 because some people have converted it to run on the cp3 pump since the cp4 was actually designed to run on european diesel not american diesel. So if pump is not a upgraded cp4 version or retrofitted with a cp3 it would be something to look at. However with a specific injector code i would say to pull the line off to that injector and flush it out just to see if anything comes out that should not be there as a precaution. As debris can hold a pintle open causing the belching of black smoke. Also depending on the injector style you may be able to seperate the upper and lower half of injector to see if pintle has debris in it. The only down side to the high pressure pump feed rail is it claims to operate at 30000 psi so a typical fuel pressure gauge wont be reccomended for rail pressure readings. Hydraulic repair/parts shops will sell pressure gauges rated for that pressure (reccomend being over rated by 10000 psi so a 40000 psi gauge will work) and hard lines made to thread on your gauge to test pressure.
Now obviously you will still want to electrically test injector ohm test, current ramp test, power and control test and test each wire in circuit along with a visual inspection of wires. This would help to rule out a bad injector or injector driver or or wire issue as a problem. Let us know what you find
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