Exhaust smoke at idle

[Captain Mal]

Starting to smoke a lot during idle only. The engine tows and runs cleanly above idle. Changed oil brands and quickly went back to Rotella. It still emits blue smoke at idle only.

Just towed from Pittsburgh to Palm Beach, Fl. Grossed 18 thousand lbs. with NO oil consumption. Truck has lots of power and gets great fuel mileage. Added various types of magic ju ju to the fuel hoping it would clean the injectors. There may be a slight improvement, but 2K miles of adding additives and it is still throwing out lots of blue smoke at idle.

Truck is out of warranty with over 120K miles on it. My dealer is in Pennsylvania but I live at my winter house in Florida. I'm on my own, what do I fix?

'01 GMC D/A 4x4 ext. sb

[Kennedy]

I guess I'd first see about getting it hooked to a Tech 2 to see if there are any irregularities in the injector balance.

[Captain Mal]

John,

Thanks for the idea on checking injector balance.
Super busy the next three days with fishing charters then Monday I must head to PA and pick up a unit going to New Orleans. I will continue with the fuel additives. If the problem persists and I make it back, the Tech 2 at some dealer will get plugged in.

Now, I'll have to find a local Tampa dealer that will cooperate in a resposible manner. It sure would be nice to have good 'after-market' repair for these engines.

'01 GMC D/A ext.sb 4x4

[pinehill]

Captain Mal,

Try Dimmitt Chevrolet in Clearwater.

[Captain Mal]

Pinehill,

Wrote that down. If I'm still smoking with the additional 3,000 miles that will be on by next Friday, I'll go there. It's got to have more personal service than huge Ferman in Brandon.

I live in Ruskin but often cross the 'bridge'.

Thanks,

'01 GMC 2500 D/A 4x4 ext. sb

[Maverick]

Mine smoked at idle last fall at the 98,000 mile mark and turned out to be #1 injector bad and stuck open and was dumping fuel into the cylinder. Glow plug was soaked when pulled. Check to see if fuel in oil. I wouldn't notice anything at all when up to speed though. Is there a big puff of smoke while in park if you hit the go go pedal? Mine did. Injector was fixed under warrenty and no other problems so far. 117,000 miles.

[OMBS]

ME AND MY BUISNESS PARTNER BOTH HAVE TRUCKS WITH IDENTICAL CHIPS,EXHAUST SYSTEMS AND AIR INTAKE KITS.HIS TRUCK HAS APPROX.25,000 MILES ON THE ODOMETER AND JUST STARTED SMOKING BLACK AND HAS A ROUGH IDLE AT TIMES,MOSTLY COOL ENGINE, BUT SEEMS TO BE GETTING WORSE.BOTH TRUCKS ARE SERVICED AT 10,000 MILES ON THE FUEL FILTER.WE RUN BOTH ON THE 110 HP SETTING FOR DAILY DRIVING AND MINE HAS NOT DEVELOPED THE PROBLEM,BUT HIS ACTS UP ON OR OFF THE CHIP AND ALWAYS CLEARS UP ON ACCELERATION AND NEVER AFTER THE ENGINE GETS WARM.NO CODES HAVE BEEN SET,BOTH TRUCKS ARE WELL MAINTAINED.COULD THIS BE A SIGN OF INJECTOR PROBLEMS?

[More Power]

1- Is air getting into the fuel supply lines & system? Can you pump air out of the fuel filter on a daily basis?

2- Unless you've just changed it, change the fuel filter.

3- Are both trucks running the same fuel?

4- Are there any codes being set?

5- If this is reproducible for the dealer, have them perform a cylinder balance test and check the fuel rail pressure.

6- Is there excessive vacuum in the fuel tank after sitting overnight?

MP

[Lone Eagle]

I would eliminate the chip as the source of the problem first. Later! Frank

[OMBS]

THANKS FOR YOUR RESPONSE.IT ENDED UP BEING THE BULLY DOG DOMINATOR.WENT BACK TO THE SPEED SHOP AND GOT AN EXCHANGE UNIT PLUGGED IT IN ,TRUCK RAN GREAT.CALLED BULLY DOG AND TALKED TO RUSSELL AND MIKE THEY TOOK CARE OF EVERYTHING.I HAVE READ ABOUT OTHER CHIPS AND PROBLEMS ON THIS PAGE BUT VERY FEW TIMES DO WE HEAR ABOUT THIS KIND OF CUSTOMER SERVICE.THANKS AGAIN FOR YOUR RESPONSE.

[Brayden]

I got my 2500HD CC SB 4x4 at the beginning of february. It has almost 10k miles on it, and as of late it has developed a rough idle, and wants to lunge against the brakes in traffic. It also smokes noticeably white. It does it when cold and hot, but only at idle.

It also feels like it's down on power below 1800 rpm's or so. Seems as if the VGT isn't mapped correctly with the fueling. Will EGR and a cat make black diesel smoke turn white? I ordered Kennedy's exhaust for an '03 to get rid of the cat, and I also ordered a pyrometer and boost gauge to help me better diagnose the problem.

Any help is appreciated. Especially techs who may know about possible software updates, etc.

Would it be advantagous to have a oil sample?

Thanks,

Brayden Fleece

[Kennedy]

Just FYI, you will likely want to fix this before doing the exhaust. The missing cat will likely be the first thing to get blamed.

Thought it said on the order 2004 LB7 Federal emissions!


Dealer can play with Tech 2 and alter EGR and turbo functions to see if it affects the smoke...

[Brayden]

Does anybody else have this problem?

Is there any way to defeat the EGR? Electronically or mechanicaly?

Thanks

[Brayden]

Nobody is experiencing this with their LLY?

[Kennedy]

At the moment, there is no defeat for the EGR that I am aware of.

Without getting into details, this is not a simple matter of unplugging it or blocking the passage.

[White Truck]

Brayden,
I have seen the symptoms you described caused by a partially restricted injector. The balance rate on the affected injector was +15. It also had a P0401 (Insufficient EGR flow) All were corrected after replacing the injector.

DKB

[Brayden]

Yeah I took it in to the dealer and we spent about a half day trying to reproduce it, and when I went to leave it started doing it.. Got it on digicam, and then pulled back into the bay and put it on the tech II. Number 4 injector was lagging behind almost 10 ms. So we're going to replace it here soon.


Thanks for the info!!

[lafrance]

04 Duramax, 2weeks old, 1400km,
Stopped at light idling, notice copious amounts of blue smoke coming from tail pipe. Engine running normally and no ses light on.Drive truck some more and it goes away, nothing visible for rest of the day...... Thoughts or ideas appreciated.
Thanks, Evan Miller.

[Kennedy]

May turn out to be an injector, but at this point, I'd see if it reoccurs. Could also be EGR related. I've seen this before, but like you said it cleared itself up.

A quick trip to the dealer wouldn't hurt. With any luck, they'll hook up Tech 2 while you wait...

[Joe Duffiney]

Three times now I have had blue smoke at idle. All three times not completely up to operating temp maybe 160 or so short trip through campground or 1 mile to atm machine. 2 out of 3 bad surge in rpm. As soon as I accelerate all is normal for a few weeks. All stock except for cat fuel filter pre/oem.