Community Forums

MJFZ · 12-20-2014, 06:31 PM

My 2003 Silverado with the LB7 Duramax has run flawlessly since I bought it new 119,000 miles ago. The past few months it has started to blow white smoke at idle and from a quick web search it seems injectors are a common cause to this problem. I know I need to address this before the injectors get worse and dump fuel into the crankcase and I know this is not an inexpensive repair. So a few questions-- can anyone recommend a competent Duramax shop in the Washington DC / Northern Virginia area? Has anyone had all 8 Injectors replaced, and what was the cost? Has anyone done this job themselves and what advise would you give, should I decided to undertake this replacement myself?

Thanks,

Mike

Piker · 12-20-2014, 07:53 PM

I had an '02 Silverado with the LB7 that i bought used in '08 and drove for about 3 years. It had ejector issues when I bought it - exhaust hazing at idle mostly, and weird injector tick/knock that came and went. I had a local shop that is familiar with diesels pull all the injectors and refurbish the ones that were bad (3 bad ones) - cost me about $2500. Ran good for quite a while... no hazing, and no noises.

2 years later, the truck started with the hazing again along with the weird tick/knock. Left me stranded one day in a walmart parking lot cause it wouldn't start. PPE tuner showed rail fuel pressure wouldn't build high enough to start. It did finally start, drove it home, and tore it apart myself this time.

I can't remember exactly how I did it, but I think I used a ball bearing inside a fuel line fitting to plug off each injector individually until I found the one that would let the engine start when it was plugged off (allowed rail pressure to build). I then swapped that injector out. I believe I ended up replacing 2 injectors @ $250 each for refurbished ones.

Replacing injectors is something anyone with a little mechanical ability can do... It's just not that much fun... the engine compartment on those trucks is pretty jam packed making it tough to reach certain bolts.

I sold the truck shortly thereafter... not because of the issues I had with it... just because I didn't need it anymore. Even though I had some problems with that engine, it was a really nice truck. The duramax/allison combo is a great running drivetrain...

-cheers

Road · 12-21-2014, 08:14 AM

Being a GM tech I have installed more than my share of those injectors. All 8 will cost you @$6000 through a dealer and I have never had a issue with a injector that GM sells but they are only good as the installer so shop around for the best most experience tech to install them. I have been using Diesel Logic injectors on the last few that I have done in my shop at home and very pleased with their injectors. It's a big job what ever you do get a good tech and do right the first time. Replace the glow plugs too. Also I have found running out of fuel will cost you a set of injectors fuel is what cools and lubricates them. Good Luck

Ray,IN · 12-23-2014, 08:35 PM

I had to have all 8 replaced while on the road about 60 miles from home. I had it hauled to the nearest Chevrolet dealership for repair. The service manager loaned us a car until repairs were completed a week later. Total repair bill was just under $5,000. They installed 8 GM OEM injectors; said only 2 were bad, but if more went bad later, that bill would also be large. The largest item was labor, due to removing all the stuff preventing valve cover removal/replacement. That was at 80,000 miles, now have 130,xxx miles on my truck, running great.

andy29847 · 12-24-2014, 05:30 AM

I have the same thing sometimes. My truck is running great (108,000 mi). My smoke seems to come and go - mostly smoking at idle after running down the highway for a while. I have a 4 step plan. 1st is get an oil sample analysis checking for fuel in the oil. Second is to change the fuel filter and fill the new filter with Seafoam. This should give my injectors the same cleaning they would get from a dealer service. Third is to take my truck to a shop for analysis. Injector balance rates and fuel pressures are part of the formula for diagnosing injector problems. Last is to replace all injectors if service is required.

fvstringpicker · 12-27-2014, 01:34 AM

The LB7 had weak injectors;so much so GM extended their warranty. Bad news is your SOL because it was 200k miles or 7 years, whichever comes first. Around west Georgia the injectors and installation averages $800 each.
Have you checked your crankcase for diesel in the oil? One way to do this is touch your dipstick to a paper towel, oil will stay in center and if contaminated with fuel the diesel will leach out in a larger ring than the oil. The white smoke can be caused by other issues.

DDDonkey · 01-01-2015, 08:34 AM

Find a good independent shop, I had all 8 of my replaced for under 4k a couple years ago. I believe if was 2k for injectors, $500 in other parts, then labor. When I sold the truck it had 176,000 miles and ran great.

Motor7 · 01-25-2015, 01:58 PM

I have an '03 D-max that is now in for injectors for the first time @ 100,000 miles. There are a few theories floating around as to why the injectors go bad, but i think the injectors themselves were guilty of a design flaw. Keeping trash out of them is a priority, so adding a CAT filter to filter out more gunk in the fuel seems to help. Replacing the metal fuel lines may or may not help(they are $500) and some say that the coating on the metal flakes off and goes into the injector. So, some mech's clean the lines, others replace them.

My guy works for a local Chevy dealership in East Tennessee and does injectors on the side at his own shop for $2500 installed and re-using your cleaned hard fuel lines. I'll let y'all know how it runs when I pick it up this week.

andy29847 · 01-25-2015, 05:36 PM

I stopped at the local (small town) Chevy dealer and learned that they would check my injectors for $75. They checked them last Friday, and they need to be replaced (108,000 mi). The price they are quoting is $5000. Lucky for me, I bought a service plan when I bought my truck a couple of years ago. Monday, the people who run the service plan are going to send their own mechanic to verify the local mechanic's findings. Here's hoping the process works for me.

Ray,IN · 02-07-2015, 07:16 PM

Quote:

Originally Posted by andy29847

I stopped at the local (small town) Chevy dealer and learned that they would check my injectors for $75. They checked them last Friday, and they need to be replaced (108,000 mi). The price they are quoting is $5000. Lucky for me, I bought a service plan when I bought my truck a couple of years ago. Monday, the people who run the service plan are going to send their own mechanic to verify the local mechanic's findings. Here's hoping the process works for me.

Keeping my fingers crossed for ya. Been there-done that. FIW, my replacement GM injectors are working fine, 50,xxx miles later.

Ray,IN · 02-07-2015, 07:18 PM

Quote:

Originally Posted by fvstringpicker

The LB7 had weak injectors;so much so GM extended their warranty. Bad news is your SOL because it was 200k miles or 7 years, whichever comes first. Around west Georgia the injectors and installation averages $800 each.
Have you checked your crankcase for diesel in the oil? One way to do this is touch your dipstick to a paper towel, oil will stay in center and if contaminated with fuel the diesel will leach out in a larger ring than the oil. The white smoke can be caused by other issues.

$800 will not even cover the labor for a LB7. Everything in the way of removing the valve covers must be removed first. Then the valve covers themselves must be removed to access the injectors and high-pressure lines.

Motor7 · 02-07-2015, 11:10 PM

I picked my truck up today. Besides the injectors he found the "common" hole in the aluminium Downpipe which rubbed against the steel power steering line. He had that TIG welded. I also had him drop the transfer case and install a Kennedy pump anti rub kit, and do a complete fluid change on the Allison replacing with a Allison approved syn oil. His bill was $2,750 and he warranties then injectors for a year.

I bought a CAT 2 micron fuel filter and adapter which goes on tomorrow in place of the oem 4 micron one.

No smoke, truck runs great, so far so good!

Road · 02-08-2015, 04:57 AM

Wow that's a great deal for you sound like your mechanic needs to go up on his prices though enjoy

jenandjon · 02-08-2015, 04:58 AM

I have a LBZ. I use Donladson filters. Get them from freightliner. NO adapter needed and you dont loose you water sensor. Just as good as Cat and half the price of GM.