Hesitation or "cough" on acceleration

[kconnair]

One of my co-workers has an '05 Duramax 2500 HD crew cab - loves the truck except for one thing: under hard acceleration (full or close to full throttle) the truck hesitates. Is this the defueling I have heard about to preserve the tranny? If this is the deal, is there any way to improve it? Truck is not modified.

It almost feels like the wastegate has opened at the wrong time. Only seems to do it in first gear. It is significant, and it bothers him. If it is "normal" at least he will have something to work with.

Thanks,
KC

[DmaxMaverick]

His turbo doesn't have a wastegate. It is variable vane. The servo that controls it, or the connectors may need some attention. Defueling during shifts is normal, but it shouldn't fall flat while staying in gear.

Also, a fuel filter needing replacement, or an air leak will cause this. Always start with the filters (air and fuel), then move on to the electronicals.

[ckt]

My 05' did this. There is an updated program available through the dealership that takes care of it.

[up@12]

Is there a website you can go to find out what updates there are for your truck without using the dealership

[kconnair]

Thanks for the tip CKT!

My friend from work took his '05 in again about the problem, and after hashing it out, and knowing almost for certain that there had to be a fix and it was not normal, their lead diesel tech listened to what he was saying, and looked up tech bulletins, and found an answer under the title "surge". It said that the tech was supposed to treat it as if the ecu was loading a certain "hard" code even though it was not, and he fixed it with an ecu flash with an updated program. Seems to have worked. He will know for sure after a few warm days, it is masked when the engine and truck are cold.

KC

[kconnair]

The warranty code listed for the problem is 1015F. That should get the service writer in the neighborhood if you are having a similar problem.

Good luck,

KC