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Diesel diagnostics guides for working techs.
Free diagnostic guides written by working technicians — not SEO copywriters. Start with a procedure you can use at the bench today. No filler, no affiliate links, no “consult a professional” disclaimers.
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Diesel No-Start Diagnosis: Where Working Techs Actually Begin
A diesel that cranks but won’t fire has three failure points: compression, fuel delivery, and air. Here is the sequence working techs use to find the fault in under 20 minutes — starting where the diagnosis actually begins, not where most techs start looking.
Automotive Wiring Diagnostics: Start Under Load
A practical sequence for isolating electrical faults, running loaded-circuit voltage-drop tests, proving grounds, and tracing a factory wiring diagram.
Coming soon
More guides in the pipeline
These topics are in production — each one follows the same format as the diesel no-start guide: a real procedure, real spec numbers, and no hand-waving.
Wiring 101: Reading a Factory Schematic
How to trace a ground circuit from the connector back to chassis — the method OEM diagnostic techs use before they touch a probe.
Suspension Basics: Alignment Angles Explained
Camber, caster, toe — what each angle actually does to tire wear and handling, and when you need a two-axis alignment vs. a toe-only set.
Diesel Cold-Start Wiring Failures
Glow plug relay faults, ECM wait-to-start signal problems, and grid heater issues that all look like the same no-start symptom on a cold morning.
LS Swap Fuel System Fundamentals
Returnless vs. return-style fuel systems, pump sizing for the LS, and the regulator math that keeps rail pressure stable under boost.
Duramax Lift-Pump Diagnostics
The FASS / AirDog install checklist, pressure targets at idle and WOT, and how a weak lift pump kills CP3 pumps three years before their time.
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The full Diesel Repair 101 course covers injection faults, compression testing, fuel system pressure diagnostics, and more — with scored drills after every module.