Duramax Diesel - Help!

[littledenny]

Can someone help me diagnose a a sick Duramax?

Have a 2004 Chev, 1 Ton, with a Duramax. Been running pretty rough of late.

It tends to idle rough, and surges at 55 Mph ( like around 1700-1800 RPM.) Nearly rattles my teeth out with any kind of load, like a steep hill. Power's down, too. When I kick down a gear, seems to run just fine, and also seems to run fine cold, but when the engine warms, starts bucking again.

My first inclination was water in the fuel, but had the filter replaced, and drained the system, little help. I've tried dryers in the fuel, also. I'm in Georgia, so it's hovering 25-50 degrees out these days here, for what it's worth.

I'm beginning to think that it's clogged injectors, but I've only run it 29K mi.

Since I'm not much of a mechanic, thought I'd see if anyone else has had the experience and/or can suggest something I'm considering.

Please, no buy a Ford, or Dodge, or a horse jokes. I'm not a real happy camper on this one.

Thanks,

[Jeff D.]

Littledenny,I'm not very knowledgable on the Duramax engine,but I've a 6.5l TD Chevy that had similiar problems.It would "buck"under acceleration,and run roughly under power.It also would stall on occasion.The problem was a inoperative lift pump.This pump draws the fuel out of the tank,and "lifts" it to the injection pump.It is mounted on the left frame rail.It makes a fast clicking sound when operating correctly.

The 6.5 would run without this pump working,as the injection pump has it's own internal pump,but it can't supply enough fuel on it's own for proper running.

I can't even say if the Duramax has a lift pump,but it's a thought.There is a forum called "GM-Diesel" that may be able to help you figure this out better.I'm sure someones had similiar problems,and you might be able to find a past post that could help you.Be warned though,some of the guys there seem to enjoy ridiculing people.I've never posted for that reason.I've no time for the insults and belittling either.

The reason I joined here is because I saw so little of that.It seems Steve runs a clean forum,and I like that!Good Luck.

[Jeff D.]

I did some research,and it appears the Duramax doesn't use a lift pump,although some were recommending the installation of one.

It looked like the most likey causes for your symptoms were (1)a faulty fuel pressure regulator(approx $800.00 installed at the dealer) (2) restricted fuel filter (3) 1 or more defective injectors.

I guess you've ruled out the easy one.(filter)

[snonut12]

I hope it would be ok to post link to another forum. This one is dedicated to mostly Duramax owners. Try this: www.dieselplace.com

[xkvator]

2004 with 29k miles - should be covered under warranty

[salesrep]

Definetly give it a double dose of a good injector cleaner. I have seen it work many times before. After a couple of tank fulls and it doesn't help at least you will have likely eliminated one possible cause.

Off Topic.
Whether or not this is the cause. I feel that folks will see and hear about more and more injector problems due to the qualilty of #2 diesel fuel.

[will_gurt]

This is starting to sound like a possible algea problem. I, as well as Digger242j, can tell you how this Kobelco SR115 DZ ran before it was diagnosed as an alge contaminated fuel system. Do this, next time that you change the fuel filter, cut the old one apart, looking for a slimy sandy looking sludge on the filter membrane, it will be darker in color. It will comfirm this algea presence. All I had to do was add a algeside to treat the fuel and change the filter and clean the sediment bowl a few times.

Salesrep, have you ever heard of this kind of problem? I am at a loss for the name of the algeside , atthis point and time. I will look that up tomorrow and post it.

[salesrep]

Yes I have seen this before. Another cheap date if this is the problem. Good "catch" Will. I do not know the otc brand biocides. sorry.

[littledenny]

Thanks, Guys - one and all.

It's headed towards the dealer soon, and it sure better be under warranty. Hate to make the 80 mile trip, but I've grown accustomed to my teeth, and I'm over riding the bucking bronco. I'll update when things get looked at, I'd hate to find a cure, and not offer the advise to save others similar pains.

And Jeff - agree, Steve runs a pretty friendly group here, and it's rare. Most forums have a select group of clowns who feel obligated to kick the guy who's down. I'm also here because of the good folks with answers.

Thanks, Steve and thanks to the gang.

[Steve Frazier]

Most forums have a select group of clowns who feel obligated to kick the guy who's down.
You'll never find that happen here, at least not for long.....

Our goal is to provide you with an environment that you all are comfortable with, this is the way information can be exchanged. You, the members have made this easy for us so far, we've had to step in only on a rare occasion. I appreciate your compliments, but it's you guys who have made this Forum what it is, I've only provided the space. Thanks! :notworthy

I hope you get that truck figured out, I know first hand the frustration of a truck not running correctly!

[digger242j]

Most forums have a select group of clowns...


You'll never find that happen here, ...

That's right. All of our clowns are just run of the mill... :)

[littledenny]

Finally got around to finding some competent dealer help with my truck.

Turns out my problem was a wire running to the #8 injector control that was occasionally in just such a position so as to rub and short out - particularly while going uphill. Since it was shorting to ground, it didn't show up on the diagostics; so it took someone with a bit of snoopability to figure it out.

They fixed the wiring harness, and the truck is fine. Zero bucks to me.

Restores my faith in the trained mechanic.

[digger242j]

Always nice to hear the happy ending! :)

[Steve Frazier]

Restores my faith in the trained mechanic.
Trouble is they are few and far between these days! Too many "mechanics" rely on computer diagnostics, unless the computer can tell them there's something wrong they can't fix the vehicle. I get so disgusted when I have to diagnose my problems to the dealer using old fashioned reason and their mechanics are unable to find any problem.

Stay on good terms with your man, he's a rare find! Glad it worked out for you.

[nedly05]

It's nice to hear that it was not a major problem with the motor, I am a big fan of the duramax, my dad has on in his one ton dump, and I am hoping to have it in my next truck, glad you were able to get back in commision!

[Dozerboy]

You guys should check out the Diesel Place (http://dieselplace.com/forum/) it's the best GM diesel forum there is and has tons of info with lots of guys willing to help.

[salesrep]

:drinkup

[littledenny]

Thanks Guys, for all the responses, guess we can put this one to bed.

Good old fashioned mechanical ability won this one, and I'm happy to see that it is still alive and well out there in the market place. :bouncegri

[CAT ONLY]

besides that problem how do you like the duramax?