Blue smoke on LMM

[1blubyu]

After I pumped diesel this morning I drove off from the station and the truck started smoking blue from the tailpipe. The smoke was visible from an 1/8th of a mile down the road. I decided to keep on going and it stopped smoking after about 5 miles.

Made a stop at the closest chevy dealer but the manager said if there aren't any codes there isn't much they can do.

This is an LMM with 2500 miles. Should I be alarmed?

[DmaxMaverick]

Welcome to the Forums!

Could have been a DPF regeneration burning off junk in the pipe. Have you experienced a regen before? At any rate, the dealer could have plugged in the Tech II and told you when the last regen was. If the timing was right, that would explain it.

Other than that, it could be a number of things. Even a glitch. The truck is still new, so there's no telling if the dealer won't work with you. They can be that way. We should (and probably do) expect more from them after spending 1/2 a house on a vehicle.

[D_R_C]

After I pumped diesel this morning I drove off from the station and the truck started smoking blue from the tailpipe. The smoke was visible from an 1/8th of a mile down the road. I decided to keep on going and it stopped smoking after about 5 miles.

Made a stop at the closest chevy dealer but the manager said if there aren't any codes there isn't much they can do.

This is an LMM with 2500 miles. Should I be alarmed?

The one thing we all should be alarmed about is "if there aren`t any codes there isn`t much they can do".

I am so sick of this comming out of GM`s service departments mouth`s I want to puke on them everytime they tell me this.
What happen to the real mechanics,there are none at GM`s I`ve been at,if there are no codes,which there can be some problems that are not linked to give codes.
This new breeds have no clue on what to do in a real mechanics trouble finding situation.

Example !
All of a sudden my charging system on my new Denali was only putting out 12.1 volts 2 dealerships,8 days in the shop.
No codes,everything checked out OK except GM from the factory installed a 615 CCA battery,a little small for all the stuff on this vehicle.

The second dealer did put in a new battery (700 CCA which is the replacement from GM) ,"BAM" everything now is working properly,voltage is 13.1-14.5 gas milage increased,trans shifting better,but they would not leave the new battery in unless I paid for it.
#%!*& "say what"
I went out and bought my own battery and now everything is working awesume,
And now both dealers can kiss my back side on future business from me.
Especially the dealer I bough 2 vehicles from the same day spending $110K.
The mechanics at this dealership don`t even up-date themselves on "anything" with the new vehicles that have come out.
"Very,very sad for a dealership to operate like this"

Oh and back to your ? "sorry for letting off steam"

Yes ! I would be concerned,mine has gone thru several regin`s,once every tank full which lasts about 20 miles, and I have 4800 miles and never had anything like that happen.
Keep a eye on it,and good luck on finding a dealership that has a old school mechanic and hope for one that has done some research on the future engine.

[More Power]

After verifying there are no codes (current or in history), and if a service manager is convinced of a problem, even an intermittent one, he might have pulled the truck into a service bay and:

1- Performed a VNT vane position re-learn (this excercises the vane position and sensor components and verifies their operation).
2- Performed an EGR valve re-learn (this excercises the EGR valve and position sensor components and verifies their operation).
3- Checked rail pressures (commanded and actual).
4- Checked injector balance.
5- Measured vacuum in the fuel system at the test port (checked for filter and/or fuel supply restriction).

I'm not sure what GM's reimbursement policy might be for dealer labor if there are no codes. This might explain why dealers are reluctant to perform more checks without codes being set.

Jim

[D_R_C]

I'm not sure what GM's reimbursement policy might be for dealer labor if there are no codes. This might explain why dealers are reluctant to perform more checks without codes being set.

Jim

That is where the problem is for "all of us consumers",the dealers claim that they do not get paid for checking out a vehicle unless there are codes to suggest repair.
If there is no codes,then they worked on the vehicle with no pay,they claim.
What they will not accept is,there are issues that can happen that don`t send codes.

Example:
My 03 Ford 6.0 dropped a valve,cause when mechanic R&R the head gaskets he did not get #7 rocker lined up properly it wore the keeper then dropped the valve.
He did the R&R with the engine in and cab on,which I feel was wrong since # 7 is practicly underneath the pass. feet.
The engine ran extreemly rough but NEVER SET A CODE.

Thank God the Ford mechanic had the common sense that there was a real problem without looking for a trouble code.

On my Denali with GM if the battery tests 11.7 or lower it would have set a code but at 12.1 GM says that is considered testing ok.
What pissed me off more than anything was the second dealer suggested that I BUY a new battery for my new car and my problems will be solved.

Any person that has any automotive voltage knowledge knows that any volts under 12.5 volts on a battery needs charged and re-tested.
And on all new vehicles the computer controls just about everything these days and proper voltage is needed to operate everything at optimum performace.

This makes me very nervous the way GM operates when issues comes up.
I can only hope and pray that my DMax holds up without major isssues,and find a dealer that has mech/techs that keep themselves up-dated on the future as well as old school.

[JohnC]

Apparently, at least on our Yukon, the PCM, under certain conditions, elects to shut the alternator off and run on the battery for a while.

[Mark Rinker]

JohnC - any idea why the PCM would elect to do this?

[D_R_C]

Actually this process is in the owners manual.
The reason is to increase and help in longer battery life :confused:
But there is a recent bulletin that states the charge might drop to no lower than 12.6-13.1 at times helping with this longer life battery mumbo jumbo.
The bulletin is for all 07 Cad,Yukons,Tahoes,Suburban, only the SUV breeds.
The problem I have is GM puts something as small as a 615 CCA battery from the factory in a vehicle with so many options.
And I could not convince the dealer that 12.1 Volts is lower that 12.6 that is stated on the bulletin.
But the replacement at the dealer if they was to break down and do a customer right is 700 CCA,interesting.:confused:
I bought the replacement for the 07 D-Max LMM which is the same group 48 size that has 770 CCA.
I am out $125 and my time waisted,but no more issues with my wife having to call me and/or road help to start the Denali.