IH maxxforce engine won't idle evenly - clues?

55 50 Ron · Mar 30, 2022

Asking for clues as to what to check for on an IH Maxxforce truck engine (actually in a school bus) that won't idle very well. It hunts up and down in RPM when it should hold steady at about 700 RPM. The hunting is from about 500 to 650 RPM. If is is accelerated to about 1000 RPM it smooths out reasonably well.

Thanks for any clues. (I'm not a diesel engine mechanic)

Phil9N3667 · Mar 30, 2022

Haven't worked on one since 2012, but could be fuel pressure fluctuating, cam/crank speed sensor. Check engine light on?

centash · Mar 31, 2022

Worn governor in the injection pump....causes hunting, as you describe

Ben

Welding man · Mar 31, 2022

A Maxforce is the one of the worst engines International ever built. Everyone in my area hates them and hardly anyone will work on them. We work on a lot of DT 466s and 466Es. You need a scanner. Get the codes and go from there. You will go broke throwing parts at this engine and you may never fix it. They have a lot of issues. Good Luck.

MARK ROBKE · Mar 31, 2022

That engine is controlled by an ECM, and you need a scan tool to diagnose it. Is there a check engine light staying on? Does it even come on when you turn the key on, before you start it? You say it smooths out 'reasonably' well- does it have a miss? Under load? Mark.

marloweg · Mar 31, 2022

engine is good it's the dam pollution crap on it that makes it a bad engine delete and remove that and thy are very good

Welding man · Mar 31, 2022

I agree to a certain extent, but very few people are willing to take the chance of the FEDS coming down on you if you get caught doing the delete. Fines and jail time if you get caught.

IH maxxforce engine won't idle evenly - clues?

55 50 Ron

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Phil9N3667

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centash

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Welding man

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MARK ROBKE

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marloweg

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Welding man

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