Author Topic: Extended engine service causing problems with HEUI Injection systems  (Read 80 times)

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Offline David.e.atherton

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This is something that all Caterpillar owners with 3126 A, B, E and C-7 and C-9 engines should be aware of. If an engine problem is diagnosed as injector failure or sticky injectors and HEUI pump not getting correct high pressure but replacement doesn't cure low power problem, cause may be the oil rail. This is can be caused  due to extended over due engine service (break down of engine and sludge build up present). Problem will show up as low power and hard starting. Many service shops overlook the high pressure oil rail and the build up of oil sludge. This may trigger event codes of 42-11 and 164-11 (Injection Actuation Pressure fault). But by now, we are throwing parts at the engine.

To resolve this, the oil rail needs to be cleaned. There are 2 large plugs at front and rear of engine that a 3/4" breaker bar will fit. Remove both plugs. Use brake clean and air pressure to clean the rail. A person would be surprised how much oil sludge is present. Then reinstall the plugs and be sure to use locktite on the threads.  To summarize;  If both event codes present along with new injectors and Heui pump and you still have low power your engine oil rail needs to be cleaned of buildup of sludge.
Dave Atherton Retired Cat Mechanic