Diesel repair 101
Working-shop entry to diesel diagnostics — compression-test baselines, injection-system faults, and the cold-start wiring that gets a truck back on the road.
Trusted on the bench
Working-shop tech and first-time builders on what the track delivered against the actual job on the floor — accessory drives, cold-start faults, factory-diagram isolation, and the harness schematics that hit the bench rail.
I bought this after a Duramax came into the shop with a cold-start complaint the previous tech could not close out. The compression-test baseline and the return-line gurgle diagnosis chapter both lined up with what I saw at the rail on a -10°F morning. Closed the ticket in three hours.
I've been a Cummins tech for nine years and the injection-system wiring module still taught me something — specifically the lift-pump relay circuit that I had been testing wrong. The schematic reads are sharper than what I learned on the job. The track certificate confirmed to my shop owner that I am current on the platform.
Good intro for someone who spent ten years on gas and is making the jump to diesel. The injector pulse-width walk-through is the highlight — I now read a scan-tool graph without second-guessing. Subtracted one star because the cold-start fuel-rail pressure module could use more on 6.0L Power Stroke specifically.
I run a one-bay mobile truck repair outfit in northern Vermont. The cold-start material paid for the course on the first call — I had a Power Stroke that would crank but not catch at -4°F and the return-line diagnosis was spot on. Would like a future module on the 7.3L HEUI injector harnesses.
Bench-tech voice, not YouTube voice. The compression-test baselines module gives you a number to write on the work order, not a vague 'check the rings' hand wave. The injector wiring chapter alone was worth the price. I share the printable diagrams with my apprentices.