Excessive Smoke....

[BlackMaxx212]

I'm running an 03 Chevy 2500HD LB7 as a daily driver - it sees about 120 miles a day. I've recently noticed much more white smoke than usual. It's just started to get colder here in Indiana, so I expect some smoke, but not this much. It only happens at idle. I can sit at a stoplight and get look back and see a huge cloud. I have also noticed that the coolant temp doesn't get past 175-180. If it does happen to jump over that mark, it comes immediately back down.

Can someone confirm my thoughts for me - I have had the injector balance test done and was told it was good. I have not yet pulled a glow plug to see if it's drenched in diesel, but that is on the plate for this afternoon. I'm also thinking maybe a thermostat issue. any other thoughts??? Any advice you can offer would be greatly appreciated!


/BlackMAXX212

[BlackMaxx212]

I should clarify too - It's not eating oil or coolant. Oil doesn't smell like fuel either. It's running 15W40 Rotella T - no synthetics. All stock parts with the exception of the K&N OEM replacement air filter. Thanks!



/BlackMaxx212

[Mark Rinker]

How many miles total? Sure sounds like you have an injector hanging up. Both of my DMaxes have had warranty injectors recently, both had clouds of whitish smoke (unburned fuel) present. The smell of raw diesel in the exhaust is the clear indicator.

GM has extended the 200K warranty to include 2003 models. Search on this forum for more information, and you'll get the info needed to make sure this is a freebie fix.

If you are over 100K, you might want to do glow plugs, thermostats, and inspect the waterpump carefully for any signs of leakage while the mechanic is under the hood with everything apart. My 2001 shucked a waterpump a few weeks after the injectors were replaced.

You should ditch the K&N filter before service work at a dealership - they tossed mine and replaced it with OEM, claiming that it was causing a code to be set on the Mass Air Sensor.

[BlackMaxx212]

Can do Mark. I've got an OEM air filter around just for that reason!

I am at 135,000 miles, and I've owned it since roughly 68,000. This is the first thing I've noticed that has been outside the diesel norms. I expect some smoke (drove a 98 Cummins before the 03 Duramax). This is just too much. I was fearing hydrolock or perhaps a bad fuel rail (hence the balance test). I do have the fuel odor to the smoke. Would that bad injector throw a code? Or should I try to talk the dealer into getting all 8 under warranty and paying for the thermostat and plugs?

[DmaxMaverick]

The balance test will rarely indicate anything "wrong". There are many more parameters that need to be looked at to get the whole picture. PWM, desired/actual rail pressure, desired/actual FPR pressure, desired/actual FPR duty cycle and voltage, and the list goes on.

When the injectors fail, it usually means either more or less fuel is being returned as is normal. Injectors can either leak internally, or externally. An external leak will fill up the crankcase. An internal leak will overfuel a cylinder, and cause smoke, and usually a knock.

Don't worry about hydrolock. The amounts of "overfueling" aren't close to what is necessary for it. Even an injector that is stuck full open can't dump in enough fuel to hydrolock a running engine. I'm not saying it can't happen, just that it is so unlikely we should be worrying about other things long before it becomes a factor. The FPR is passive, so when you turn the key off, the FPR dumps rail pressure (or is supposed to, anyway). Also, by the time you have that much leakage, you will be having a permanent limp mode, and probably only one bank even firing (engine protection mode).

[BlackMaxx212]

Thanks for the advice guys! I called in to my dealer, and the truck will have an appointment early next week. I explained my issue of the smoking, and they said one (or more) of the injectors could certainly be at fault. I will see how they want to deal with it. I only want to make one change at a time (the system engineer coming out in me). I will be heading down the injector road first. I'll post back and let you know how it turns out!

Thanks again!!!!!!!

[BlackMaxx212]

I got the appointment all set at the dealer for Monday (04 DEC 2006). The Service Manager seems to agree that it is over-fueling and is probably injector related. He also said that if one injector is found bad, they will automatically do all 8. He's got the parts on hand already, and if found faulty (which he seemed to think one would be based on the symptoms), the truck gets new injectors all the way around. We'll see!

[Mark Rinker]

You may want to inquire regarding the injector lines as well. Early design allowed condensation to pool around the flare nut, causing corrosion. When the line is disassembled, and subsequently reassembled to a brand new injector, the bits of rust and crud can find their way into BAD places.

There was a guy on Ebay selling OEM takeoff sets, but I just searched and don't see any listed currently. GM retail for set of 8 lines is nearly $1000 - and I was told they weren't covered under warranty when I had my two trucks done. If they give you that runaround, I have an extra set I'll sell you. Email me at mark_rinker@hotmail.com

I think even an old set of lines could be cleaned up properly with a good parts washer and some careful cleaning of the flare nuts. However, injector replacement requires a SUPER clean environment, and starting with a fresh set of injector lines is probably the best way to go if you have rust or corrosion in this area.

[JohnC]

Check the oil to be sure it hasn't been diluted with fuel!

[BlackMaxx212]

Thanks Mark! I don't think they'll do that to me. That dealership is usually pretty good about that stuff. I've had good luck with them in the past. If they do go there though, you will be hearing from me!!!

JohnC, the oil is good (so far). It's not eating any and It's not "making" any. No fuel odor in the oil either. We'll see what the shop says on Monday!

[GRGaither]

I have a '02 LB7 w/216K miles. Injectors were replaced at 167K for excessive smoking. Started smoking again at 215K, just as bad as before. Really bad white smoke at idle and acceleration.
Local diesel mechanic suggested trying some 4-Power by Conklin. 16 oz. in a 1/4 tank of fuel, followed by 3 oz. of Diesel Power by Conklin in a tank.
Did this on a trip hauling a trailer to Ohio, all smoke was gone when we returned to Indiana.
Smoke has not returned and is running great. I am a believer.

Gary R. Gaither
Kokomo, In.
grgaither@aol.com
'06 GMC 3500 LBZ
'02 GMC 3500 LB7

[jbplock]

Gary,

Interesting ... your good results peaked my curiosity :) ... just checked the Conklin website (http://www.conklin.com/catalog/products.asp?p_divID=1050&p_catid=49&p_divname=Vehicle+Lubricants&p_catname=Fuel+Conditioners) and noticed that according to the 4-Power MSDS (http://www.conklin.com/products/msds/1545-1.msds.pdf) it contains 20-40% methanol which is not recommended for GM Diesels. I don't doubt your results but I don't think it would be wise to use the methonol based 4-power on a regular basis.

:)

[BlackMaxx212]

I agree with jbplock on that - I am of the opinion that alcohol is a bad idea as a whole in any diesel additive. When it burns off, it produces water as a by-product of the combustion. That can't be good for the fuel lines or any other metal parts (moving or not) that it comes in contact with - especially in a closed system. The results GRGaither had were great though! I'll still run that by the shop guys in the event they give me a hard time with the injector replacement tomorrow. MarkRinker - I haven't forgotten about the fuel lines either. If they send me around that side of Robin Hood's barn, I'll be in contact!

Thanks to everyone for their input!!! I'm learning at ton about the Duramax that will help me make it run as good if not better than it should!!! I'm not new to the diesel scene, but every bit of input from other folks running the same or similar motor helps!!! Thanks!!!

[BlackMaxx212]

UPDATE:
I just got the truck back today after a new set of 8 injectors (covered by the new special policy on the 2003's). Numbers 7 and 8 were both WAY out of spec. I also ended up with a new injector sleeve on #7 and new fuel lines and was told by the dealership those were covered as well. They didn't show up on the bill anyway :) THE SMOKE IS NOW GONE! Only smoking appeared on cold startup when it should. THe dealership was really on the ball about the whole thing. Nothing to complain about at all - they were all class. Courtesy vehicle and all per the policy (no cost to me) - no questions asked.

Thanks to everyone on this forum for your input and advice!! I'm still going to put some more miles and a few more cold starts behind it and see how it behaves.

Thanks again!!!!!

[GRGaither]

Let me clarify the use of Conklin's 4-Power in my '02 GMC LB7. I was aware it had menthanol. This truck has approx. 215,000 miles when it started smoking really bad. The previous injectors were replaced under warranty at 160,000 miles, because of excessive smoke. No warranty replacement was possible at this time, because of the miles on the vehicle. Being faced with replacing the injectors at my own expense, approx. $1,500 to $4,000 depending on who does it, I felt I had nothing to lose. If it didn't work, I replace the injectors, if it did, I saved a lot of money.
I felt that only a one time shot of 16 ounces to a quarter tank of fuel was not enough to cause problems. It is not recommended for continuous use. Directions say once every 4,000 to 8,000 miles.
It cured the smoking with one 16 ounce application and saved me the cost of injectors and a week of down time.

[DmaxMaverick]

I don't see a problem with ocasional use of methanol. The Duramax fuel pump is not near as sensitive to lubrication quality as the previous Stanadyne D pumps. Continuous use could cause problems with corrosion, but I don't think there will be any short term effects. That's great it worked for you. Nothing wrong with saving a little (or a lot of) money. I would have done the same thing in your situation.

[BlackMaxx212]

Given the situation if it had been me, I think I would've done the same thing - alcohol in the additive or not. Injectors aren't cheap, and the downtime for the work to replace injectors isn't short.....

[Mark Rinker]

I wish this thread had started earlier, would have tried it first on one of my two LB7 Dmaxes that just got new injectors. You would think that if this could solve or extend the life of failing/plugged injectors, GM would have a treatment less expensive than replacement!

(Then we'd all be bitching that they use this cheap workaround to push us over the 200K mile warranty mark...)

[BlackMaxx212]

Isn't that the truth Mark! We'd still have new injectors in the end though...... Those extrusion seals and injector sleeves seem to be quite problematic as a whole on the LB7's according to the shop guys that did my new set. The LLY's have issues with pins, and I don't know about the LBZ's, but I'm sure they have their gotchas too. They still work too well for me to give up!

[Mark Rinker]

Agreed. The Dmax's overall are a great product and we are just now starting to see clear trend lines in engine maintence as we reach the 7th year of production!

I wish there were a way to make the injectors easier to access and replace, making them more of a user-serviceable item. Something that could be easily reached by pulling the front wheels and the fender wells sorta thing, instead of removing nearly all the accessories and wire harnesses from the engine.