Home » Duramax LLY » Duramax LLY – ENGINE DIAGNOSIS – Engine Stalling

Duramax LLY – ENGINE DIAGNOSIS – Engine Stalling


1. Air leaks in fuel lines.

2. Fuel filter partially plugged by wax formation, dirt/sludge, or partially water filled.

3. Misfueled, wrong fuel, or low quality fuel.

4. Restricted air intake due to plugged filter element, air cleaner, intake duct. Generally caused by extended off -road operation in dusty areas.

5. Fuel supply pump problem or restriction in fuel lines, injector pump, or injectors.

6. Fuel drain back or return lines restricted/damaged.


1. Check lines from fuel pump to injectors. Replace lines that leak or have damaged fittings. Tighten loose injectors. Bleed injectors afterward.

2. Drain off filter contents at draincock. Clean out fuel tank and lines if filter contained sludge. Clean out filter if full of wax or dirt.

3. Drain and refill tank. Drain fuel filter and bleed injectors.

4. Replace filter if necessary. Remove and clean out air cleaner body, intake duct, cap, hoses, and dust unloader.

5. Check fuel flow at pump and injectors. Supply pump minimum pressure is 5 1/2 psi. Replace worn, damaged, or failed parts.

6. Inspect and repair or replace lines, clamps as needed.


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