Engine: Cummins 8.3L
Complaint: heavy black smoke
Technician Notes: Smoke disappears when number 5 cylinder is disabled by cracking the line.
First, they brought us the injectors – no faults found.
Today they brought us the pump, with a request to bench test. Yup. Over-fuelled, all right. Idle output 0.8 mm3 on cyl’s 1-4 & 6. 27mm3 on cyl 5. We also found the rack traveled beyond 22mm, which for the non-technical guys out there, mean something’s broken inside. There’s a pin which is supposed to limit the travel. Usually when this pin breaks, it’s because excessive force was applied to the shut-off lever. However, the solenoid and lever on this pump all looked ok… at first.
Upon closer inspection, we noticed the solenoid had been replaced, and the lever removed and reinstalled to accommodate this replacement. When the lever was removed, the woodruff key (presumably) fell out or was removed then forgotten. In any case, it’s not there anymore.
This explains why the internal rack stop pin broke. The broken pieces of the pin fell into the rack teeth, causing the barrel rotating pin to break off.
Had the technician who replaced the solenoid noticed the missing key, we wouldn’t be doing this job today.