Blue Smoke Issue

[Homesteader]

I'm puzzled about my blue smoke symptoms. I've seen blue smoke at idle 3 times; heavy blue smoke when I accellerated from idle those 3 times.

I've used 1 quart of oil since the last change in about 3,000 miles (Rotella Syn). Dealer says injectors and compression are good. I'm at 90,000 miles on my '03 LB7 (CA) and haven't used oil before. I believe I have a fuel dillution issue from injectors that happen to be behaving now. I am puzzled by 2 of the 3 occurances that took place just after an oil change. Once at 85,000 miles and just yesterday when the dealer changed oil at 90,000. Pretty impressive blue smoke, but yesterday there was also a massive cloud of grey smoke. This was just after leaving the dealer's oil change. Is it possible that there is oil collecting during the crankcase fill, allowing it to get into the intake? We're watching the oil level now, hoping to establish either consumption or dillution, but the after-oil-change blue smoke is strange. Any thoughts?

[Mark Rinker]

Welcome aboard!

Never heard of this one, but it sure sounds like oil getting into the intake during the change process...possibly CA emmissions equipment EGR valve related?

A good 'driveway test' to determine if you are loading up with fuel is to idle the truck for 30 minutes, then take a test drive with moderate acceleration, immediately upon leaving from the idle location. (Please plan ahead for a safe location to do this test - i.e. don't go ripping through your neighborhood on my account ;) )

If you get a cloud of blue/white/grey smoke on that first acceleration after idling, but it clears up, you most likely have an injector dumping fuel at idle that is collecting in the exhaust system. It should then be apparent to any quailified technician when they examine injector return rates with a scan tool...

[Homesteader]

The results of an extended idle and drive off were just like you described. The puzzle is the rates were all in spec prior to leaving the dealership. I've heard that testing in park vs. neutral will alter results. Can the scan tool info be intermittent and multiple scans be required? What would I need to constructively communicate to a tech regarding an attempt to try again (He's already spent a day on my behalf including a compression test)?

The EGR and Cal emission issue could be associated but I doubt it. Too much opportunity to throw a code and none exist. I'm a bit pushed in that all the Chevy dealers I know are closing and I'd like get this done before heading back to Montana in July, and certainly before I run out of warranty in September.

[Mark Rinker]

Possibly a stuck/bad EGR valve, rather than bad injectors? This is where my knowledge on the topic ends - from an operator point of view...

Maybe one of our GM techs will chime in here.

[Homesteader]

The injectors are unloading at idle and fuel is going into the ehaust. The "post-oil-change" querry I had is simply the fact that the truck would idle while it warmed up and the oil was checked. While they're just not bad enough to justify replacement yet, I'm sure they will be bad before the warranty expires.

[NutNbutGMC]

The injectors are unloading at idle and fuel is going into the ehaust. The "post-oil-change" querry I had is simply the fact that the truck would idle while it warmed up and the oil was checked. While they're just not bad enough to justify replacement yet, I'm sure they will be bad before the warranty expires.I don't get it. When would be a good time to replace a failing component?

These early LB7s are continuing to deterioate with life expectancy. Been through 4 sets myself.

[mattb5150]

Did the dealer tell you the injectors were "unloading during idle" ? I think I may have same issue.

Matt

[Homesteader]

Yup. Had a conversation with them describing what was happening and what to expect. They will get worse over time. My best hope is to make certain they do before the 7 years runs out as I only have until October. Meanwhile, it seems that the crankcase oil darkens sooner and I've got the after idle smoke. Otherwise no ill effects.

[mattb5150]

Just dropped off mine at the dealer, mine is also smoking heavy black smoke upon acceleration, I mean heavy. We'll see what they say, estimate to diagnose $185.

[mattb5150]

The #7 injector is the culprit, but of course it does not exceed the values for GM to cover the replacement. Mark Rinker, how have you used the Sea Foam? I bought 2 pints, kind of leary of filling the fuel filter with it.

BTW I was on Hwy 101 yesterday and a Chevy Dmax was ahead of me blowing black smoke like mad at highway speeds I mean BAD! I would think the California Air Resources Board could go after GM (Government Motors) for gross polluting!

Matt

[Yukon6.2]

Hi
Seeing how it's goverment motors now,it wouln't mater,the goverment has it's own rules,completly different than the rules that the average person has to follow:rolleyes:

[Homesteader]

If it's Government Motors, I wonder if I can take it to the Motor Pool at one of the local military bases.

[Duramaster]

Keep driving and see if it gets any better. This type of fuel treatment will sometimes fix injectors (like flushing gas engine injectors) and other times it just turns out to be a band aid.