LesJ

[LesJ]

no tagI have a 2004 LB7, 114K miles, and pull an 14K Alpenlite 5-er.the engine runs good and has a lot of power, but if it sits and idles for a while, when I get under way it emits blu-wht smoke for about a mile. Then it clears up and even under heavy load does not smoke. New injectors at 75K miles,Dealer installed. Are the injectors worn out again or is there something else wrong????

[Kennedy]

This does sound like it could be injector related, BUT I have been hearing more and more lately from CA LB7's (EGR equipped) with issues so I might be inclined to start there with testing.

[More Power]

Sounds like you may have an injector that is leaking fuel into a cylinder, which accumulates and then burns off at higher power settings.

An injector balance rate test should show which injector it is. You could do a couple of things at that point... 1- Try a fuel treatment that helps clean the nozzle. 2- Change just that injector.

A while back I spoke with a midwest fuel shop that also services these engines. The owner told me that ATF used as a fuel treatment tends to keep combustion byproducts from accumulating on the nozzles. He discovered this after changing a set of injectors for a customer who ran ATF as fuel treatment for a long time. They discovered the nozzles were clean when disassembled for rebuild. In addition, he says a pattern emerged when changing injectors for a "white smoke at idle" complaint. In those trucks, the nozzles had a lot of combustion residue buildup, which he theorizes interferes with the nozzle sealing. The AFT injectors didn't have that.

I don't know... There are two camps concerning the use of ATF. I'm OK with it in a truck that doesn't have a catalytic converter or diesel particulate filter. The various additives in ATF could poison the rare earth elements used in each. A 2007+ certified fuel treatment would be safer, but I don't have any definitive info about their effectiveness in keeping nozzles clean.

Jim

[LesJ]

Thanx for the tips. I thought injectors should last longer than 40k.

[chrisinkanata]

More Power - any indication of how much ATF was added? I would suspect a similar result with Stanadyne.

[Kennedy]

I'm not so certain this would be your injectors although it does lean that way. I've seen the LLY trucks do this intermittent blue smoke when almost new and it was EGR related.

That said, I also see this same scenario play out over and over as it seems some get 40 k others 120k etc. It repeats almost with certainty at the same or even shorter intervals and I attribute it to local environmental conditions: ie Fuel quality. Why else would it vary AND repeat consistently?

Tech Tip: http://www.kennedydiesel.com/docs/Duramax%20Injector%20Failures.pdf

[More Power]

More Power - any indication of how much ATF was added? I would suspect a similar result with Stanadyne.

When I use it I add a quart per tank. Can't prove it or quantify it, but my sense is that my LB7 runs a little smoother and with less idle surge after/while using ATF.

Incidentally, a while back a fellow told me that he had been using high concentrations of cleaned/filtered/recycled used ATF in a stationary diesel genset. The engine was eventually disassembled for rebuild, and they discovered some piston deterioration that he attributed to the use of ATF. The edges of the piston crowns were eroded. Maybe it was or maybe it wasn't due to ATF. He thought it was. In any case, I've not heard from anyone who regularly used a relatively low concentration of ATF who reported any effect on the pistons - like a quart in 26 gallons.

The currently available commercial diesel fuel treatments should provide the same or better results. The benefits with those include other things like cetane improvers, added lubricity, injection system cleaners, fuel stabilizers, corrosion inhibitors, and more.

Jim

[gimpyhauler]

I just need to add my '07 LBZ (175,000mi) used to produce a dark smoke cloud anytime I stepped on the pedal more than "necessary." I'd leave a dark cloud behind me. Passing a vehicle would put them through a dark cloud as I passed. Recently bought a diesel additive from Kennedy. Now it doesn't seem to matter what I do, I can't get it to produce a dark cloud anymore. I've done nothing else that would change the cloud production. I'll stick with what seems to work for me.

[lmholmes11]

Gimpy hauler my LBZ does the same thing as yours did. I have 66k miles on it.