Duramax towing “engine reduce power”
 

I was towing from Cincinnati to BG. When I hit the hills of Ky my
truck shut down with the reduce power limp mode.
Had the truck towed home. I have replaced the fuel pressure
Relief valve. Also installing a Air Dog fuel lift pump and replace the 6”
Rubber fuel supply hose at the motor.
Just trying to cover all the bases
Has anyone else had this problem?
Truck runs good with no problems without trailer .

Thanks for any suggestions
David

Re: Duramax towing “engine reduce power”
 

Does it give any DTC codes? Mine did it and I would get "low pan rail pressure". I tried everything, lift pump, relief valve. The only thing that fixed it was replacing the injectors. I know that's not what you wanted to hear but I fought it for awhile before replacing the injectors.
Dan

Re: Duramax towing “engine reduce power”
 

I think the code was PO 87. and a code for high intake
air temperature
We was able to place a scanner on it while I was having
trouble and all the injectors was balanced and appeared to
be good.
But I not a diesel mechanic . If problem happens again
I was thinking injectors or cp3 pump. Both $$$ repair not
knowing for sure which is bad.

Thanks
David

Re: Duramax towing “engine reduce power”
 

Which model Duramax? I have had that issue on LLY's and it is usually the relief valve. Replacing them seems to help for a short time. I have found shimming the original with a .040-.060 washer works well.

Re: Duramax towing “engine reduce power”
 

It is a 2008
I found a shop that changes the valve from a 2 stage
Valve to a single stage.
The 2 stage opens at a high pressure and stays open till
The pressure drops below a low pressure setting

The single stage opens and closes at same set point

That my understanding of how the valves work.I could be
mistaken on operation of the valves

Re: Duramax towing “engine reduce power”
 

On my LBZ 2007 Silverado was getting a low fuel pressure code. And would only happen when towing the trailer. Took it to a friend who has lots of experience with these engines and run a diesel repair shop. Replaced the injectors and problem cured. Not sure if this is the same issue you’re having but thought I’d share my experience.

Re: Duramax towing “engine reduce power”
 

Mine is also an LBZ. I bought a tuner that would check balance rates too. But it only checks them up to 1500 RPM. I also installed an AirDog system. The only thing that fixed it was replacing the injectors. I was told that it has to do with how much fuel was being returned .
Dan

Re: Duramax towing “engine reduce power”
 

Thanks, can the injectors be sent and tested or is it a waste
Of time and just replace the injectors?

Looks like injectors are 350 to 450$ each for reman.