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Cpt
09-18-2014, 20:21
I have a new to me 2004 LB7 with 135,000 miles. Upon any type of heavy acceleration I get black smoke. Similar to when I had a built 6.5. The oil pressure also drops from 60 psi to 30 while cursing to just above the red while idling. The oil hasn't risen and does not smell like fuel. It smokes black when pulling a 4500 pound trailer up a hill and seems to load up.

I get 19-20 mpg while cursing at 70 mph.
Is this normal?

MajMike
09-19-2014, 10:48
Maybe the IP is turned up a little high?

Cpt
09-19-2014, 11:29
What does IP stangd for. Is this something I can adjust?

DmaxMaverick
09-19-2014, 11:52
What does IP stangd for. Is this something I can adjust?

IP = Injection Pump

Doesn't apply, as he meant it, to Duramax Diesels. It's specific to 6.2/6.5 Diesels.

Black smoke means more fuel attempting to burn than there is O2 to burn it. If your programming and equipment is stock, then the diagnosis should be simple. First, check the air cleaner. Dirty or restrictive in any way will cause black smoke, but should also cause the SES lamp (Service Engine Soon) to come on. Next, check the wastegate, making sure it is firmly closed. If the linkage moves at all, the actuator is broken or loose. To locate the wastegate actuator, find the rubber hose located at the compressor housing outlet (center/rear/top of engine, under the decorative cover). At the other end of that hose is the wastegate actuator pod.

If you have any power-adding equipment or programming installed, don't begin troubleshooting beyond the above before completely removing them. Then, repeat the smoky condition in full stock form.

MajMike
09-19-2014, 15:09
Doesn't apply, as he meant it, to Duramax Diesels. It's specific to 6.2/6.5 Diesels.

My bad.