LB7 Intermittent Exhaust Haze - Chevy and GMC Duramax Diesel Forum
01-04.5 LB7 Duramax Powertrain Discussion of components that are directly involved in the power production and all that is needed to get and keep the truck moving . Engine , Transmission, Etc.

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post #1 of 11 (permalink) Old 07-09-2019, 07:29 PM Thread Starter
 
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Exclamation LB7 Intermittent Exhaust Haze

Hello all,

Need any advice I can get. Bought my first diesel about a month ago, its a 2003 GMC Sierra CCSB Lb7 one owner completely bone stock(well it mostly is as of now). It has an exhaust haze at idle that is sometimes almost non-existent and sometimes easily noticeable. Its not a full on white smoke. I've had the balance rates checked and there is no fuel in oil from what I can tell. I've been reading up on so many possible things and could use some real world advice. It doesn't appear that anyone has been in the engine at all so I'm assuming injectors!?!?

Thanks in advance for any knowledge sent my!! way

2003 GMC Sierra LB7 CCSB 4x4
S&B Air Dog II 4G 165 Beans Sump
For now...........
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post #2 of 11 (permalink) Old 07-09-2019, 07:33 PM
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Could be injectors, cups, could be headgaskets. What were the balance rates? Tested return rates?

My name is Nic
2012 qcsb 6.8L cummins, 48re swapped, ratchet shifter with pcs vb
2011 GMC Sierra 2500 CCSB LML,
Lil ole single s400, fuel,
supporting mods,
rancher tuned,
Various parts from SDP, WCFAB, LDS, DHD, FREEDOM RACING ENGINES GDP, EXERGY, ATS.
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post #3 of 11 (permalink) Old 07-09-2019, 07:54 PM Thread Starter
 
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Balance rates were damn near perfect all but two were less than -1/+1. Two were around 1.5/2.0. Didn't get the return rates checked as it was a buddy of mine scanning it on his lunch break where he works. I read somewhere excess air in the fuel could cause it but I can't find a leak anywhere. Not even at the fuel filter head. I planned on installing my Air Dog next weekend and bypassing the filter head to see if that would make it go away. It runs great aside from the haze/smoke.

2003 GMC Sierra LB7 CCSB 4x4
S&B Air Dog II 4G 165 Beans Sump
For now...........
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post #4 of 11 (permalink) Old 07-14-2019, 09:31 AM
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Sorry to hear about the hazing .

It would be of interest to know more about the truckís history and mileage.

As you have probably learned through search, statistically VCO injectors in our LB7s seem to begin showing signs of failure (hazing or long crank times or both) at around a 70k cycle. YMMV, of course.

Also, search balance rates and you will learn they tell only part of the story on injector failure.

High return rates are typically caused by erosion of the ball and seat in the injectorís internal return circuit. Iíll let you explore that further on your own.

Finally, the dreaded ďhazing at idleĒ is most often an indication the injector nozzles are not sealing properly, allowing fuel to drip when they should be off. The accumulated, carbonized fuel on the tips gradually deteriorates the spray pattern and along with excess fueling, most notable at idle, causes the hazing. Above idle, the tiny amount of dripping fuel is largely inconsequential and owners can be frustrated because other than idle haze and some loss of mpg, the truck seems to be operating well. I tolerated that situation for months, till my wife became too embarrassed to ride in the truck.

Again, based upon the experience of many other owners Iíve read about here, I feel comfortable saying injector replacement is in your future and recommend you investigate SAC injectors as replacements. They were used in all Duramax following the LB7.

Keep in touch. A wealth of accumulated knowledge and experience here.

Best

2003 GMC Sierra 2500HD SLE ExtCab CA Emissions; 155k; Allison 1000 w/Transynd X2 Flush & Fill; 8' bed; AFE/CAI; MBRP 4" Exhaust; Side Tint, 33% VLT, rear, Limo; Smittybilt Stainless Side Nerf Bars; Sprayed-in Bed Liner; MadJack Fuel Filter Access Door; Regular Used Oil Analysis (latest available on request), Blackstone Labs; EGT/Boost Gauges; Dual Chrome Dipsticks, JC Whitney; Stainless Steel fuel filter head bleeder screw; New WP and Hydroboost; Billet Aluminum Fuel Filter Housing Spacer; Professionally repaired instrument cluster (new steppers and lamps); Does anybody ever read this s%#t?; Injectors under warranty @ 70k; 2nd set DIY @ 155k
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post #5 of 11 (permalink) Old 07-14-2019, 10:11 AM Thread Starter
 
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Thanks Steve. I have been researching a lot and had came to the same assumption. The truck had 181k when I bought it and I’m currently at 183k. I negotiated a pretty good deal on it because I figured it either needed injectors or would in the near future. Don’t have much of the trucks history as it was traded in to the Chevy dealer I bought it from and wasn’t a private owner type of situation. The car fax shows a lot of periodic maintenance but none of it is detailed or says “injector replacement”. I have been looking at injectors due to fear of a leaking one costing me an engine. Who carries SAC injectors and is a reputable place to source them? Thanks for the info it’s greatly appreciated !!!

2003 GMC Sierra LB7 CCSB 4x4
S&B Air Dog II 4G 165 Beans Sump
For now...........
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post #6 of 11 (permalink) Old 07-14-2019, 03:31 PM
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Yo Chuck,

While a very few owners have checked in with high mileage LB7 injectors (150k), they are as rare as teddy bear poo.

Maybe someone did a DIY injector job on your new ride, which would explain no paper trail.

$5,000+ at a dealer, somewhat less at indys and maybe $2500 DIY.

Most of our faithful vendors monitor this Forum (enlightened self-interest ) and offer their products when they read of owners with problems.

Search is quite effective and you should be able to track down suppliers quickly.

Finally, VCO, LB7 injectors originally became available in oversized fuel delivery (expressed as %) and required engine management tuner hardware to take advantage of the higher flow rates. I believe I recently read here of VCOs that provide OEM fuel delivery but donít recall the supplier.

Best

2003 GMC Sierra 2500HD SLE ExtCab CA Emissions; 155k; Allison 1000 w/Transynd X2 Flush & Fill; 8' bed; AFE/CAI; MBRP 4" Exhaust; Side Tint, 33% VLT, rear, Limo; Smittybilt Stainless Side Nerf Bars; Sprayed-in Bed Liner; MadJack Fuel Filter Access Door; Regular Used Oil Analysis (latest available on request), Blackstone Labs; EGT/Boost Gauges; Dual Chrome Dipsticks, JC Whitney; Stainless Steel fuel filter head bleeder screw; New WP and Hydroboost; Billet Aluminum Fuel Filter Housing Spacer; Professionally repaired instrument cluster (new steppers and lamps); Does anybody ever read this s%#t?; Injectors under warranty @ 70k; 2nd set DIY @ 155k
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post #7 of 11 (permalink) Old 07-14-2019, 03:40 PM
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Lincoln diesel specialists is who you're thinking of.
Paging @[email protected]
[email protected] likes this.

My name is Nic
2012 qcsb 6.8L cummins, 48re swapped, ratchet shifter with pcs vb
2011 GMC Sierra 2500 CCSB LML,
Lil ole single s400, fuel,
supporting mods,
rancher tuned,
Various parts from SDP, WCFAB, LDS, DHD, FREEDOM RACING ENGINES GDP, EXERGY, ATS.
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post #8 of 11 (permalink) Old 07-14-2019, 04:25 PM
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Quote:
Originally Posted by SilverGorillaLML View Post
Lincoln diesel specialists is who you're thinking of.
Paging @[email protected]
https://lincolndieselspecialties.com...injectors.html
[email protected] likes this.

04 GMC LB7 2500 SAC 45 injectors DSP5 EFI live from LDS, ported air inlet. 4" MBRP droning exhaust.
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post #9 of 11 (permalink) Old 07-16-2019, 06:40 AM
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Check us out here at LDS for all your injector needs.

https://lincolndieselspecialties.com...injectors.html

Looking for LB7 Injectors?
Check these prices out!

......... Lincoln Diesel Specialties
Phone: 920-361-7700


Click here For,
LB7 Injector Install Instructions
post #10 of 11 (permalink) Old Today, 08:26 AM Thread Starter
 
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Exclamation Lb7 Injectors

Ok, long time overdue replying to this thread as work has been retarded busy. I got my Air Dog installed a while back and failed to turn down the FPR on the Air Dog itself started the truck and immediately blew the "water in fuel" sensor out of the bottom of the fuel filter. 🤣😂 That made a mess real quick!! Ended up bypassing the filter head, truck is running great. Installed a PPE boost increase valve. Have down pipe, turbo horn and 4in exhaust (its my daily don't want it to be obnoxiously loud) on order.


Going to pull the trigger on injectors in the next day or two....... With that being said need some advice.

Do I go NEW Bosch, SAC 00 or SAC 45%?? I do plan on doing an intercooler, drop in turbo, tuning and all the piping in the near future.

Can I run the 45% for a short period of time until I get tunes? I would hate to do injectors and need bigger ones a couple months down the road. Are the S&S remans any good? I've been looking at them primarily on DMAX store and Lincoln Diesel for a while now.

Send some knowledge this diesel newbie's way.

Thanks
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