Reduce Engine Power Duramax

[Jrhummel6]

does anyone know the true fix for reduce engine power? this may happen once in a months time and some times it will happen multiple times 2 mins or 10 min apart. I normally just turn off the truck and re-prime the fuel, and it will be fine or sometimes it will do it again 5 min later. It does it only when on the highway or getting on the on ramp and giving it gas.

I even read that it will rest if you leave the truck off which I have done that before and it started and drove fine? I just don't get it, how is it loosing prime #1 and re-priming it will get it going again, but then 2 leaving it off for awhile it will fix it self?

Its not the fuel filter, I have read it could be the fuel pumps, injectors, the fuel body or fuel body connection, I have no idea!

Any help would be great tired of messing with it. I live in Plano if anyone knows a really good diesel repair guy close.

Thanks

[jmoore2006]

The hand pump on top of the housing would be my first place of looking. Especially if you use it to prime. I’ve had a few leak air in there and under a heavy load get the reduced power. They are a pain to track down for sure and make you hate a good truck. Good luck

[Strummer]

The hand pump on top of the housing would be my first place of looking. Especially if you use it to prime. I’ve had a few leak air in there and under a heavy load get the reduced power. They are a pain to track down for sure and make you hate a good truck. Good luck

This , the hand primer pump is easy to rebuild too . Takes maybe 20 minutes. The orings wear out . Also the plastic bleeder screw sucks I change mine out to brass ones . I have also had problems with the oring on the heater plug .

[Jrhummel6]

This , the hand primer pump is easy to rebuild too . Takes maybe 20 minutes. The orings wear out . Also the plastic bleeder screw sucks I change mine out to brass ones . I have also had problems with the oring on the heater plug .

I replaced the orings etc. on primer already

[Jrhummel6]

no help?

[bowhntrmatt]

Never had it happen. What year?

[125Dad]

The housing where your fuel filter screws on is cracked. My guess

[Low Fence]

I have an 01 duraflop that does this everyday. Has since it was new. They have replaced everything on it so many times I can’t count...still just goes to idle at road speed.

Only when pulling though. Empty, it has never done it

[Black Ice]

no help?

I just checked my Cummins manual and it said call the Duramax guy for his Allison.


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[Bassdeer]

What year? I have an 05 and my CP3 INJECTION PUMP went out, kind of acts like that. First I thought it was the Fuel Rail Pressure Sensor and changed that but no go.

[Pedernal]

I have an 02 that will lose prime or used to lose prime. I would rebuild the fuel pump filter/prime pump head and it would be good for a few years. About 5 years back I went to the second generation Duramax fuel pumpi filter/prime pump head and have not had a problem since. As stated above, some will develope a crack and lose prime. supposedly the second generation one is a better system and fits the first generation duramax you just have to get longer fuel lines.

My truck would never go into the reduced power mode however, occasionally it would not start until I would prime the system.

On several occasions I read that installing a fuel lift pump would resolve the issue. Additionally, I read it was really bad for the injectors to run on reduced fuel flow. I have 180K on my first set on injectors that need to be replaced.

[LivinADream]

Mine does this when the truck idles for a long time, or driving slow on back roads for a long time. Without getting up to highway speeds, it doesn't Regen, and the next time you do get up to highway speeds it throws it into reduced engine power.

I've also had the cracked fuel filter problem, bit it wasn't causing reduced power. It would just die a few seconds after cranking, then I would have to prime the pump and it would be good. Replaced the whole housing and haven't had trouble since.

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[stinkbelly]

How reduced is the power? Will it just not go or is it just really sluggish? What does it feel like?

[Acameron52]

Trade it in on a Powerstroke.

[Dale Moser]

Trade it in on a Powerstroke.

Then you can have reduced power all the time!