03 Duramax Rough Idle

[T-top87GN]

Started up the truck today and was very unhappy to find that it had a rough idle. The block warmer died this past week so I haven't been able to plug it in.

I figured it was just a little cold so I let it run for a bit and it was still idling really rough. A slight push on the throttle, not even enough to raise the RPMs, will smooth the idle out.

Anyone have any idea what's going on with this thing? It's just one more frickin' headeache I don't need right now.

 

[85HOT-T]

check the air cleaner. You really dont need the block heater, we only plug ours in when it is below 0 out. Heck we have not even pluged it in once this year.

Does it smoke at all? How rough is the idle? How long has it been doing this?

 

[dgreen1069]

One of the most common issues with any of the current diesels is a dirty fuel filter. It needs to be changed at least every 15k miles. How long has it been since your last filter change?

 

[T-top87GN]

Haven't checked the air filter yet but I will go down and check that in a bit.

The fuel filter was changed 10k ago.

There was ALOT of smoke when it was running this morning. After it started warming up it was fine, but there was still a tiny bit of smoke at idle.

 

[Turbo Indian]

post that question here http://www.dieselplace.com/forum/index.php

 

[Quick6'n'-K.C.]

What color was the smoke? Black or white?
How cold is it there?
Get some diesel 911 at your local truck stop and add it to you fuel tank if you get to the point where you think its just fuel related....
My 99 powerstroke wouldnt fire this morning,.. go figure, it was 15° out.
BW

 

[85HOT-T]

Just out of curiosity, is this your first diesel? The rough idle could be norma, diesels tend to be rough on a cold start up. If the temp in columbus is anything like it is here it was cold this morning. Ours fired up fine with no block heater, smokes good till it warms up, but what do you expect on a cold diesel engine.

 

[dgreen1069]

He's right, when it is really cold out you can expect your diesel to run rough until it warms up. It will also smoke quite a bit till things warm up. The smoke is usually whitish on a cold startup.

 

[TurboDave]

Haven't checked the air filter yet but I will go down and check that in a bit.

The fuel filter was changed 10k ago.

There was ALOT of smoke when it was running this morning. After it started warming up it was fine, but there was still a tiny bit of smoke at idle.

First of all, I'll disagree with those that claim a rough idle is normal when it's really cold out. Not so, or at least not normal.

When mine suffers that problem (once or twice a year, but my fualt), it's because the fuel was starting to gell up. Once it acted just like yours, rough idle, smoothed out with more accelerator. So, I took it out heading for the store, about two miles later, it really jelled up and totally shut the truck down.
Mostly my fualt because I didn't "dope" up the fuel enough for the weather. My truck likes to be "doped" at about twice the recommended blend. Once I started using at least twice the recommended blend of anti-gel, I haven't suffered any more problems.

 

[T-top87GN]

Thanks for all the input guys.

Yes this is my first diesel, but I have never had it run like this during the past 2 1/2 years I have had it. It's like it has a cylinder that is not hitting at all. I mean it's making the truck shake enough that the shifter it moving around. Give the accelerator a little step though ( and I mean little, the RPM's doesn't even go up at all) and the engine smoothes out and is fine.

I'll give the 911 a try but I add winter additive/cetane booster with every tank in the winter. I'm used to it running a little rough in the winter cold, but this is really rocking the truck back and forth from missing so hard.

 

[Quick6'n'-K.C.]

You do realize that chewy trucks are notorious for having injectors going bad on them because of crappy fuel filters.
If its under warranty, i hope you kept the reciepts for the fuel filter changes, or take it to them to get it the filter changed.

If it shakes real bad at idle, most likely bad injector. What kind of cetane booster are you using?
Try the 911 and see what happens, how cold did it get there?
PS, i put your link in my sig awhile ago because too many people were asking where to find that type of CD :biggrin:
BW

 

[T-top87GN]

Hey Bryan!

Yeah I know about the injector problems and I have one of the LB7 engines, it's a 2003.

It was pretty cold here the last couple of nights. I think it was around 10 last night.

I've kept the filters changed but doubt I have the reciepts. I change them myself and I use the Bladwin filters for the fuel and the oil.

I won't pay them a single red cent for a bad injector. I know all about the problems they have with them. If they tell me it's an injector I will change it myself.

Thanks for the link in your sig! I have been shipping a new version of the manual that now includes a program to install the whole disc to your hard drive. I have also changed the label from an inkjet printed label to a LightScribe label. I was planning on posting pics and info soon but just haven't done it yet. I guess I'll have to do it now since I mentioned it.

 

[T-top87GN]

Well I'm taking it to the dealer today. The problems I've had with this truck have made this all a little disheartening. I always figured, at leas the motor will run forever. Guess I was wrong on that was well.

I was planning on buying it after the lease was up.

 

[Turbo Indian]

I always figured, at least the motor will run forever. Guess I was wrong on that was well.

unless you are doing alot of towing diesels are not for you. I don't care what most think,but these small v8 diesels are not going to hold up like the ones in class 8 trucks. my old boss hated diesels and said he would never buy any of us one. 90+% of our work trucks went 200+k heck some of us had over 300k on gas motors. these were mostly 1 ton's that were over loaded & abused. why do I drive a diesel you ask? I do alot of towing, this new GMC will have a trailer hooked to it 95% of the time. if someone says well I bought it because it gets better milage than a gas, do the math. gas engine 13mpg diesel 16 mpg, ABOUT 3-5 mpg difference. the diesel is about $4500 option? you can buy alot of gas for $4500. also diesel is & is going to stay more expensive than gasoline for a while. damn I almost talked myself into a gas motor!

 

[suicide six]

Diesels require more maintenance than a gasser.Changing oil and fuel filters at same time is recommended.A clean air filter cant be overlooked.Injector pump lubricate with gas fill up is a good idea,along with some sort of tank cleaner included.You wouldnt believe the things that grow in that fuel.Rad additive once or twice a yr is aidful.These things are much more costlier than a gas vehicle just to prevent more costs.

 

[85HOT-T]

Diesels require more maintenance than a gasser.

We dont do a thing to ours but oil and fuel filter changes, diesel 911 here and there, and they run fine. We had one of those Awsome 6.5 POS rebuilt gas block engine deisels. Over loaded its whole life ran 300k with vrry little matinence. Just the usual, 2-3 injector pumps, again a POS, heads rebuilt once or twice and thats about it.

 

[Quick6'n'-K.C.]

Ive worked on diesel powered heavy equipment for about 12 years, the ONLY thing ive seen grow in diesel tanks is algea..that stuff is nasty.
HERE YOU GO..

http://en.wikipedia.org/wiki/Diesel


Algea, microbes and water

There has been a lot of discussion and misinformation about algae in diesel fuel. Algae is a plant, and it requires sunlight to live and grow. As there is no sunlight in a closed fuel tank, no algae can survive there. However, some microbes can survive there. They can feed on the diesel fuel.

These microbes form a slimy colony that lives at the fuel/water interface. They grow quite rapidly in warmer temperatures. They can even grow in cold weather when fuel tank heaters are installed. Parts of the colony can break off and clog the fuel lines and fuel filters.

It is possible to either kill this growth with poison, or eliminate the water, a necessary component of microbial life. There are a number of poisons on the market, which must be handled very carefully. If a poison is used, it must be added every time a tank is refilled.

Regardless of the approach there is still a risk of filter clogging. When microbes die their skeletons may still be in the tank. Once a microbe colony grows there will be a persistant problem.

 

[buickpower]

that is crazy, never even heard of that before! is that common?

 

[Quick6'n'-K.C.]

Diesels require more maintenance than a gasser.Changing oil and fuel filters at same time is recommended.A clean air filter cant be overlooked.Injector pump lubricate with gas fill up is a good idea,along with some sort of tank cleaner included.You wouldnt believe the things that grow in that fuel.Rad additive once or twice a yr is aidful.These things are much more costlier than a gas vehicle just to prevent more costs.

I dont have to worry about the injector pump lubricant
My cummins uses DIESEL FUEL to lube the main injector pump and i change my oil every 3-4K and fuel filter every 15K...

What i think you meant to say is IF a diesel engine breaks it will cost the owner more money to repair than IF a gas engine breaks because when diesel engines break, they usually break the bank :biggrin:

Knock on wood, other than buying mine, it hasnt dipped into the piggy bank for repairs since i purchased it. Just turned 39K last week.

The algea is common, but mostly in equipment that is filled from jobsite fuel tanks with the algea in the water... Not so common at your local fuel stop.
BW

 

[T-top87GN]

Well I just got it back from the sop and they could not reproduce the miss.

I'm guessing I just had a clog, I dunno.

I had them fix the block heater too and go ahead and change the oil while it was there.

$360 later here I am. Oh well.