I just bought a 2003 duramax. Picking it up next Saturday.

I took it for a test drive today and the truck had no power for about 5 minutes or so.. I started it up and let it idle for about 10 minutes before I went out. It was cold today.. about +10F. After driving for 5 mins the power was there.. I love the truck and it's under factory warrenty still, so I bought it. Figured if it's not normal I'll get it fixed at the dealer.

Is this normal? Does the dmax prevent you from going over 40mph when cold (eventhough I did let it idle for about 10 mins)?

i've read something on the allison tranny at allison's web page. in cold operating temps it may inhibit some gears from operating until it gets to higher temps. it is a good idea for you to let the truck to warm up a bit before driving.

The transmission definately was not shifting but I don't think it was in a high gear. From a dead stop the truck moved.. Nothing great but it did move. I just couldn't get it up to speed. It felt like it was in 1st gear but just no power.. There was no need to shift gears at that speed.

:confused:

Had the same thing happening to mine today, truck feels like it's starved for fuel, you step on the pedal but it just dosen't want to go very well, but will still idle ok.
It's most likely caused by the fuel filter starting to wax up. Have the dealership change the fuel filter, espically if it's been a while since last change or if your not sure when it was changed, before you pick it up and put some conditioner in the fuel.
Or have the dealershp put it in the heated garage overnight and take it for a spin the next day, if it runs normal again then it was the fuel waxing, if not then it might be something more complicated.

I just bought a 2003 duramax. Picking it up next Saturday.

I took it for a test drive today and the truck had no power for about 5 minutes or so.. I started it up and let it idle for about 10 minutes before I went out. It was cold today.. about +10F. After driving for 5 mins the power was there.. I love the truck and it's under factory warrenty still, so I bought it. Figured if it's not normal I'll get it fixed at the dealer.

Is this normal? Does the dmax prevent you from going over 40mph when cold (eventhough I did let it idle for about 10 mins)?
What you describe is normal. These engines (any diesel) do not make power until they are warmed up.

Mine makes plenty of power fine, even this morning in -3 temp I had all the power I needed. It is a bit sluggish, but I have never had a problem getting up to speed or the like. I usually baby mine until the thermostat is at 130+ before I work it a bit harderer.

I vote for possible fuel filter waxing.

Mine makes plenty of power fine, even this morning in -3 temp I had all the power I needed. It is a bit sluggish, but I have never had a problem getting up to speed or the like. I usually baby mine until the thermostat is at 130+ before I work it a bit harderer.

I vote for possible fuel filter waxing.Ditto on making plenty of power. Because, my LLY makes pleanty of power when cold however, I do baby it until its up 130-40+ same as you just to get the engine fluids up to temp and flowing through the engine


:ro)

-3...10*F......that's just not right, but I suppose you guys are used to that stuff. When it gets in the 20's here I am thinking about summer already. I could definately see the need for fuel conditioners in those kind of temps.

Yeah,

I had that problem last spring while camping in the mountains at 8,000 ft. Temps overnight in the 20's. Got in the truck and someone was rushing me (I usually warm-up until the volts are up) and put her in gear and....whew what a slug! I was worried and tooled out to the main road slowly and finally after five minutes or so she got the power back. Never had the problem since, I think a little warm up keeps her happy!

Regards,

Monleywrench+

My only concern is that I did let it warm up for at least 10 minutes. As soon as I got the keys from the dealer I started it up and then checked the truck out.. Pop the hood.. check for leaks, play with the controls inside, etc.. If I started it up and just jumped right in it without letting it warm up that would be a different story. But I didn't. Strange thing was that the power did eventually come around. Would a waxing fuel filter cause something like that to happen? Very sluggish at first then work fine?

Also, I live in central NJ. Anybody know of a good GMC/Chevy dealer in the area? Someplace that see's a lot of Duramax's?

Thanks for all you help guys.. Really appreciate it.

Letting the truck idle for ten minutes before you leave does help the engine and internal fluids warm up, but it's not a cure for a gelled filter. Remember that the fuel filter is to the side of the motor, not in the warmest spot it could be like the old 6.5's were. So when you let the truck idle it's not doing much for the fuel filter, BUT when you drive it around some and build more heat the fuel recirculates back to the tank quicker and with more heat and eventually warm's the fuel in the tank and the fuel filter and in turn it un-gell's the filter. That's why after you let it idle and drove around some with no power the fuel evenually warmed up enuf to un-gell the filter and the power came back.
Try the truck again after the dealer put the truck in a heated garage all night and gave the fuel and filter a chance to warm up. If it has power right at the start than I am pretty sure it's the filter waxing up.
I have had truck's start, run down the road for 10 miles, and THEN start to gell up with reduced power and have to let the truck fast idle for 3 hours before I could make my way home.