OMG it isn't the injectors, but what is it

carjcapt

New member
Jan 22, 2016
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02 LB7 with 230+ miles started to blow (kinda white) smoke at idle then when gassed bunch of blue (oil) smoke until at speed then clear and is still running great but the mileage is down about 1 mpg.

Took it to a shop and they determined that the injectors are fine (replaced at 170K). Looked for oil residue in the intake hoses and found none. Not sending fuel into the crankcase.

They determined its the valve guides or cups are bad sucking oil into the combustion chamber causing the blue smoke.

Suggested that I just drive it while putting in a quart of lucas oil with every oil change.

Do I need heads...or just blow it up...

Help....
 

prostreeter600

Street rodder
Jul 18, 2010
893
7
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Dallas Tx
I had the exact same problem on an LBZ , mine was a hole in the intake runner of the head . I got a bit carried away with porting . It was the external side of the intake runner not the dividing wall. So at idle where it's like a normally aspirated engine it would suck air in and in doing so it would suck oil from under the valve cover section of the head . When I gassed it driving it , it would clear up due to it now having boost (positive pressure) but my PCV reroute hoses were plowing oil due to boost pressure getting into the crankcase . Welded it up and all was good .
 

Chevy1925

don't know sh!t about IFS
Staff member
Oct 21, 2009
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I would suggest the check and make sure the pcv in the alternator bracket isn't plugged
 

THEFERMANATOR

LEGALLY INSANE
Feb 16, 2009
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What test did they do to determine the injectors were ok.
What he said. My bet is still injectors with those symptoms. Balance rates only tell part of the picture. And if they're not correcting the balance rates, then find a shop that knows how. Also make sure they check them with the rail pressure ramped up to 160. I've seen SEVERAL trucks that have had clean bills of health from dealerships have bad injectors, so just because 1 shop said they're good, that doesn't gurantee they are.
 

Brent@LDS

Vendor
Vendor/Sponsor
Aug 23, 2011
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Wisconsin
What he said. My bet is still injectors with those symptoms. Balance rates only tell part of the picture. And if they're not correcting the balance rates, then find a shop that knows how. Also make sure they check them with the rail pressure ramped up to 160. I've seen SEVERAL trucks that have had clean bills of health from dealerships have bad injectors, so just because 1 shop said they're good, that doesn't gurantee they are.

X2^^, I agree!
 

delong_1

<< my work
Dec 5, 2008
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Blue smoke isn't injectors... Not saying they aren't bad being an lb7. With those miles turbo seals, valve stem seals, guides, rings etc are all well used and probably letting some oil get burned.
 

THEFERMANATOR

LEGALLY INSANE
Feb 16, 2009
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Blue smoke isn't injectors... Not saying they aren't bad being an lb7. With those miles turbo seals, valve stem seals, guides, rings etc are all well used and probably letting some oil get burned.
Blue smoke CAN be injectors. I'm not saying it couldn't be burning oil and causing blue smoke, but with the other white smoke at idle, my bet is still on injectors. Blue smoke is oil burning, but diesel is fuel OIL. So bad injectors CAN cause blue smoke.
 

carjcapt

New member
Jan 22, 2016
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Want to thank all responses.

The smoke at idle doesn't smell like raw fuel. The shop plugged in a ODB scan tool and determined the balance was good. As far as the turbo is concerned we pulled all the hoses and found no oil residue. Being an old mechanic from the 50s and 60s is does have the signs of valve guides and/or valve stem seals. Having said that it runs very well and will run at red line in 5th gear with nary of any smoke white, blue, or even black

I think I'm going to run it for mosquito control and at oil change use a little Lucas oil with the delo any one recommend atf in the fuel???

Tks again
 

carjcapt

New member
Jan 22, 2016
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I would suggest the check and make sure the pcv in the alternator bracket isn't plugged

Again the FNG is asking for some advise. Nothing has change (haven't had it worked on either). I did look at the tube where the PCV is located and found it wet with oil but not enough to get any drops to the floor.

It is still starting and running fine as a mosquito control truck for brief amount of time upon acceleration and it blows Blue smoke then goes away followed by the lovely black smoke of burning just diesel. The oil level hasn't change and did the white paper test to determine if there is a diesel fuel stain along with the Delo oil it was negative.Attached is a photo of same

The smoke at idle is mostly white with a very faint blue tinge then oil blue upon initial acceleration.

We sold our 5th wheel and hopefully get funded tomorrow if it happens we will have the opportunity to go by Van, Texas have Top Notch Diesel take a look.
 

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carjcapt

New member
Jan 22, 2016
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Dropped off the 5th wheel and on the way back home stopped by to see Josh at Top Notch. With some OBD diagnosis Josh determined that the #2 cylinder injector is toast. So I have some decisions to make, get new tires, replace one injector, or 4 or all 8, and last but not least sell it to a person that I would tell about all the problems and get ???? dollars. Its still a good truck no damage except for wear and tear, 233000 miles, one owner (me) with all records (if that means anything at this point)

What to do?????
 

carjcapt

New member
Jan 22, 2016
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Just to let everyone know Josh is a first class Gentleman and if he wasn't 200 miles away he would be my mechanic. A stand up guy.
 

clrussell

pro-procrastinator
Sep 23, 2013
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Dropped off the 5th wheel and on the way back home stopped by to see Josh at Top Notch. With some OBD diagnosis Josh determined that the #2 cylinder injector is toast. So I have some decisions to make, get new tires, replace one injector, or 4 or all 8, and last but not least sell it to a person that I would tell about all the problems and get ???? dollars. Its still a good truck no damage except for wear and tear, 233000 miles, one owner (me) with all records (if that means anything at this point)

What to do?????

Put a set of tires on it, a set of good Bosch injectors in it. And drive the wheels off of it. I'm sure it's paid off so throw $4500 at it and drive it a few more years.