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knocking noise in cyl 6 Help!
Hey members, new here. I have a "knocking" noise in my 1990 Dodge 250 Cummins 5.9 engine. I bought this truck with no noise, but a leaky injector pump. I replaced a seal, put it back together and now have a knock in cly 6. I goes away when I loosen the injector line. It in NOT noisy on cold start, but makes the knock noise after about 30 seconds. It stays after that. (Checked rod and main bearings, and they look good. No metal in oil, bottom of piston not cracked or cyl wall galled, checked valve tappet clearance, no issues!)
I switched injectors with cylinder 2 and the knock is still at cyl 6. Advancing the injector timing makes it louder. (turning the pump toward the top of the head) and quieter when retarding it. (turning the pump toward the oil pan).
What am I missing here? What is this "fuel knock" I keep hearing about, but still do not understand completely. Any ideas anybody? Can I damage the engine if I keep driving it this way? Thanks again for any help! DeVere