Cat 3126 "surging"

ohiomike08 · Nov 28, 2012

The straight truck I drive has a Cat 3126 in it, and today it started "surging" when ever there is a load put on the engine. The only time I really noticed it, was when I was climbing any uphill grade. The oil pressure and temp are fine. After running for several hours today, the check engine light came on, and the engine "shut down" and I couldn't get it to go more then 45mph. Stopped, shut it off, checked everything I could, started it back up, and it ran fine, other then the surging. Any ideas as to a possible cause???

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zorry · Nov 28, 2012

What year ? Recent pm ?

davekc · Nov 28, 2012

Could be several things. Is it cold? Fuel freezing or water in it. Check the fuel seperator and fuel filter. How old are they? Then look at air filter.
Then since it threw a code, what does the code say? That will narow it down if it is a speed sensor, low fuel pressure sensor, low air intake sensor which effects the turbo functions.
Lastly, make sure your tranny fluid isn't low. Gets too low it will cause a surge as well under load.
Any of those will "D" rate the engine.

ohiomike08 · Nov 29, 2012

Sorry, should have included this info in the beginning. 2000 FL80, just had the objectors rebuilt a month ago and a PM at the same time. I'm going to give everything a good look in the morning, when I have better light.

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comet_4298 · Nov 29, 2012

Stop and get the code looked at and go from there.

ohiomike08 · Nov 30, 2012

comet_4298 said:
Stop and get the code looked at and go from there.

If I don't get a load tomorrow, that will be my priority Friday.

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Deville · Dec 1, 2012

How many miles on the truck? Auto or manual transmisson? When was the last valve adjustment?

RETIDEPXE · Dec 1, 2012

Deville said:
How many miles on the truck? Auto or manual transmisson? When was the last valve adjustment?

All the above are good suggestions.

The most common thing on my Cat when surging and D rating on a climb is the Racor fuel/water separator FL uses, bowl has shrank slightly, o-ring on water drain plug shot (techs tend to over tighten this), bowl to housing o-ring not installed right, filter clogged from junk in bad fuel, usually a change in bowl and or filter takes care of it. The fuel/water filter will be 1/2 to empty when this happens but not low enough to see it thru the see thru if that makes any sense, it will still be full.

Deville · Dec 1, 2012

You know if you get in a jam you can use a regular closed ended fuel filter on that.

I have to check the drain pug on mine occasionaly it get's lose.