Duramax LB7 Injector Failure Explained - Diesel Insights

You've heard about LB7 injectors and how they're prone to failure. In this episode of Diesel Insights, DT's Nick Priegnitz explains the manufacturer shortcomings that created part of the problem. The other issue is that the injectors are located under the valve covers requiring a hefty price tag to fix. Nick also describes the importance of keeping tabs on injector balance rates with an Edge CTS 2.
LB7 owners are probably aware of the need to keep an eye on their truck's injectors. If not, hopefully, this video will highlight the importance of staying up to date on the injector health of your LB7.
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[@klondikenewfie6430]

Everything I’ve ever researched, read or seen in regards to injector failures were caused mostly by contaminated fuel (water, dirt,air,) There’s a reason GM introduced a 200,000mile warranty on injectors. As long as a Filter change Was done every 20,000 Like he said in the video, low lubricity ever since mid 2006. All injectors for the duramax from 2001-2007 were designed for low suffer Diesel (500 ppm ) not ultra low silver diesel ( 15 ppm). I own a duramax and have over 540,000 on original injectors. I also don’t trust big fuel companies saying they use lubricity additives in their fuel. I use XP3 Additive. 1oz every tank And sometimes added a couple ozs of a high quality 2 stroke oil

[@highdesertjohn]

I love the abundance of information I all of your guys videos, you are bringing the power to the people by sharing your knowledge I know we all appreciate it, thanks fellas, and I look forward to purchasing from you in the future.

[@Duramaxtuner]

We really appreciate your kind words, High desert John. That's our goal - share what we know to help you make decisions. Again - thanks a ton for the comment - it means a lot to us!

[@SP33D3M0N03]

"Torque them using a torque wrench, for the love of God!" Hahaha shit had me rolling

[@alabama7636]

Thank you for the great video simple and to the point.

[@drygraphite]

My old LB7 needed injectors at 80K and again around 170K. I just had my LMMs done two weeks ago at 183K. Now on to a full EGR delete to chase off a P0401..The joys

[@traceylockhart1847]

I just changed injectors. Cant get it to run. Scanner says open circuit. What causes that

[@white24valve]

First again!!D.T. number 1 in the country! And a LB7 topic..my favorite!!

[@daletractor6637]

Great video!!

[@dieseldad5192]

GREAT INFO!

[@morgantreasure7387]

Nice video, thanks. I have a 02 with 240,000 and still ripping! Hopefully the injectors will hold out with the regular maintenance I have done. Best truck I have ever had, hands down!

[@Duramaxtuner]

For sure - good luck!

[@hey_youtubeim_back2159]

Doing a job on an lb7 with 241k on the clock. Get ready...your on borrowed time

[@paul_omalley]

Good info here! Love your videos!

[@Duramaxtuner]

Thanks Paul!

[@jamesdeanvegas]

I got a haze kind of but I have a full open exhaust. Not sure if that matters. But I also run a tune and my balance rates are good. So not sure if injectors are bad.

[@gwebster77725]

This the second time I’m having to replace mine gotta love a damn lb7

[@bfe671]

Gavin Webster when you replace your injectors you need to do all the other fuel system upgrades; CP3, lift pump, better fuels, etc. just like the guy in the video says.

[@dandonaldson3819]

My 2001 2500HD Had The Injectors Were Replaced By Recall & A DealerShip, Replaced Them All With All Modifications That Were Done 2 the Truck 🙏🏻👍🏻

[@TimsWorkshopTJY]

Just replaced my 2001 LB7 at a top notch shop. The new injectors work great. Plenty of power and no more smoke. We tow a 32ft 5th wheel with it. The shop gave me the diesel additive they use and put some in every fill up. In case you are wondering I had 150k on it.

[@cd1538]

Just came to grips that my 01 LB7 needs injectors at 192k mileage

[@TimsWorkshopTJY]

just make sure to put the additive in every fill up and it will last you along time if you don't get on it like i see some guys do. the Heads do go out too and gaskets so take it easy on it. fyi

[@4g63tpowered]

Straight forward!

[@Dannkyu]

How do you know that the injectors are new than 2007? I just bought a set of new Bosch injectors and wanted to know if it's written on the injector.

[@jesusrico2347]

thanks for the information you share

[@Duramaxtuner]

You bet!

[@Sembrandolasemilla777]

So whenever you change the injectors you have to drain the crankshaft?

[@johnv1038]

I know this is an old vid, but if y’all are still paying attention I’ve got an LB7 250k and I’ve had the number 7 injector shit the bed twice in 50k miles. Is it possible there could be some sort of a harness issue? All the resistance values are good, and I’m super ocd. About my maintenance schedule. I got a lift pump and two 2mic cat filters, and a 10 mic cat separator. Any info would be a great help thanks!!

[@jeromeg3890]

Thanks for the video , i have a 2015 Chev Duramax just lost my fuel system for the second time first at 66,000 km and now at 166,000km just 6000km over my warranty . $12,000 repair bill here in Canada , i have had several duramax's in the past but this will be my last. They had a good truck there a ruined it trying to get more horse power and better fuel milage out of the same engine , should just lift it alone .

[@vatoloco1776]

I have an 05 Chevy 2500 HD Duramax it has 260,000 miles and replace fuel filter to a cat conversion clean my injector every 50,000 miles with x66p injector cleaner. With live efi tuned on demand program deleted egr I smoke mustang all day . Also tow a 3 car hauler part time . You just got a lemon 🍋 . I have a barber that got a new 2020 Ford 2500 .3 engines in a year no tune all stock 🍋.

[@TheSRMproject]

Just spent 7500 on my '03 DirtyMax on 8 new boshe injectors, gaskets and ARP studs. I blew a head gasket and said screw it im gonna do it all while its torn apart.

[@Duramaxtuner]

Sounds like a well placed investment.

[@TheSRMproject]

maxo kream nice man. Not a bad price either. My mechanic sent my heads out to esentially be rebuilt . Running smooth and sexy now.

[@johncasor9698]

on my 2005 duramax with 278k miles the head gaskets failed so i pulled off the heads and when do i have the injectors serviced or changed out??? engine runs great but maybe because of the spray tiny holes are now bigger from wear and i do not need them to get to the point where they shoot a full stream out and drill a hole in the piston... have you ever seen a injector drill a hole in the top of a piston ???

[@keithhendrix9338]

Is there any video you guys can recommend me to to change out a fuel pressure regulator on a 2002 Chevy 3500 LB7

[@drewkring9600]

Keith Hendrix not to be rude....but it’s KZbin....just type it in. If you can’t figure that out, it’s probably a little to difficult of a repair. I was going to do mine, but I just paid a mechanic to do it on half the time. It’s not very simple

[@sirsweetness8332]

Good video. Looking to buy a Duramax

[@turtlezed]

i WAS looking to buy a Duramax but after watching a few vids on this engine I think I' will look at something gas instead.....

[@JasonY02]

Could yall make a video explaining the injector degree spray pattern. People have tried to explain I just get lost

[@Duramaxtuner]

We can put that on the list!

[@MultiScrot]

im looking to to replace my injectors do you have a opinion on good injectors i should get? im not looking for race injectors or anything just decent injectors that will do the job

[@Duramaxtuner]

We only deal with the best, Exergy Performance: duramaxtuner.com/fuelsystems.html

[@radosawbitans1523]

Super.

[@jamespollock3668]

What's your opinion on a lift pump? I heard that will help injectors also

[@Duramaxtuner]

Yes. Lift pumps can help, for sure.

[@codyyellott117]

Lift pumps are a must

[@LouieD-nl9ih]

Hey I will be changing my injectors soon I’m looking to get to that 650hp Will the stock Bosch injectors make that or do I need 30 or 60 over injectors thank you

[@bobbybushong9551]

U need at least a 30 over

[@Blackneck1994]

Do you guys think the VCO design plays a part in premature LB7 injector failure? If I'm not mistaken, LLY and newer engines have SAC nozzles?

[@Duramaxtuner]

Not really. We produced a podcast with Exergy Performance, makers of performance fuel systems (including injectors, pumps) and they talked in great detail about the LB7 injector and some of the known issues - here's the episode: traffic.libsyn.com/dieselperformancepodcast/exergy.mp3

[@stevewaclo167]

Nick, while the reasons for LB7 injector failure you list are accurate, I'm sure you will agree those problems are common to all injectors, yet LB7's continue to be the most failure prone among all manufacturers. That being said, my research and discussion with an engineer at Bosch indicates the hazing problem (hot start issues are another issue) is related to the VCO (valve covered orifice) design of the originals which requires continuous internal contact of the pintels to the nozzle. Leakage during the "closed" cycle causes buildup externally, with resultant poor spray pattern. I have yet to find a product that deals with that failure mode. One more thought, LLY injectors switched to an SAC design (look it up) and injector hazing issues, in my understanding declined dramatically. I'm due for a new set at 155k (originals at 75k under warranty). Thanks for your good advice!

[@dieselman6.664]

Steve Waclo clearly Bosch is going to say it isn’t there design with curtain things. Hazing at idle is 95% if the time due to tuning or injector problems. The Bosch injectors are rated at 2 micros the duramax is at 8-12 at best on oem. With cat adaptors you can get it down to around 4 micros. The problem on the duramax in the fuel system are in two main parts. Poor filtration and no low pressure fuel pump. Both can be fixed by simply adding a lift pump. People would rather save $700 dollars than add what their truck needs from the start.

[@turtlezed]

i remember a time (in days very much gone by with mechanical injection) when injection pressures were around 150 atm and even then injectors were being pulled at fairly low mileages.....now the fuel is worse, the pressure in rails has sky rocketted and the factory filters have not really improved , to the point where people are fitting their own setups because factory filter just doesnt cut it........they dont want them to last....its got to the point where i am teetering on the dge and may just opt for a gas engine instead and have average motoring bills like normal people do....

[@dieselman6.664]

turtlezed unfortunately your right they don’t design things at the factory to last anymore but the good thing is that with all the diesel techs around the US that want to be called the best they have created competition and actually designed parts that are almost failure proof. Sac nozzles for example not existent on lb7 till a tech made them then even the oem was redesigned on the lb7 to a sac nozzle. Competition and not putting cheap parts to replace is the key to millions mile trucks

[@tommyt2854]

@@dieselman6.664 I just picked up a bone stock 1 owner '03 that's "making oil" (I knew that when I bought it, still on the back burner for repair) What are some areas/mods you feel I should address? Thanks.

[@stevewaclo167]

@@tommyt2854 Go to Duramax Forum for enlightenment, loiter for a bit, use "search" then ask good questions..

[@traviscoppersmith8405]

I have a 2003 LB7 and I have a haze should I just Chang my injector tips?

[@Duramaxtuner]

With an LB7 we never suggest changing just the tips. That is most likely not where the problem is. Also, we suggest properly diagnosing the injectors before replacing them. Check balance rates, look for fuel in the oil.

[@danthompson1467]

I did all this and it ate dam injectors like candy . Got rid of it after 6 sets of injectors went to the 6.0 gas best thing I ever done

[@Duramaxtuner]

That's heart breaking to hear. Maybe you can look at a newer diesel when you're done with the 6.0L.

[@kdbritt48]

I would like to know what injectors yall recommend? I replaced them and only got 80 thousand miles out of them and they need replaced again. Thanks

[@Duramaxtuner]

Exergy Sportsman Injectors have the best we have used. 815-568-7920

[@charlesswearengin2404]

VGT Lighting Bolt turbo solenoid $450.00 It's suppose to increase 5 to 12% boost, faster spool, quicker torque, cleaner burn, less soot, and better mpg by changing the vein position. Any response to this? Saves the cost of a turbo swap and labor involved. I think this new, and I'm very interested in it.

[@slabaugheli]

Question. For the lbz would you recommend replacing the high pressure hard lines? as you would the lb7. Or are they two completely different horses? Thanks for the vid! Great stuff.

[@SP33D3M0N03]

Eli Slabaugh all common rail fuel hard lines are a "one time use" line. They match to each injector/port on your fuel rail when you torque them down. It's always highly recommended to change them. But, sometimes... if you're good you can get away with it. You didn't hear that from me, because reusing lines is bad advice.

[@white24valve]

Nothing is better than new

[@turbosupra2jzdragracingtob249]

What more important? Injector cleaning or fuel Lubricity?

[@codyyellott117]

Turbo Supra 2jz drag racing Toby Gear Head kinda the same thing keeping good fuel addictive and make sure to have them cleaned they will last

[@tracykooken2606]

I DIDNT KNOW ANY 03 DURAMAXSCAME WITH water seperation ... its not in my manuel nor mentioned in any sevivie stuff !!! y r they not making a better REPLACEMENTS ??

[@cohenb7695]

I just had my truck tuned and strait piped and it just started sputtering and blows white smoke when it sputters any ideas of what it could be?

[@Duramaxtuner]

Could be cold weather, could be a few things. Check for codes or take it into a reputable diesel shop.

[@benbuttars5594]

S&S diesel just announced that the SAC00 injectors replace that factory failure completely. Have you heard anything about that? If they have fixed the problem, my injectors are on the way out and I would kill to have injectors that lasted a long time

[@Duramaxtuner]

They sound great but, we have not worked with those yet.

[@codyyellott117]

Just saw these want some input before buying them

[@white24valve]

I use Optilube...red label..yellow label..orange label!!

[@lwilliam22]

DuraMAxFanatic q6

[@SCRAMBY18]

Would a lift pump eliminate premature injector faluire?

[@whocaresaboutme29]

No

[@whocaresaboutme29]

You need a netter fuel filter system.water and separate fuel filter.big rigs have filters galore..if chevy put sum great filters on the duramax would be great..

[@davidphillips3953]

The sheer number of people happy they can go 100,000 miles on a $5000 set of injectors is mind blowing!

[@obscurefortress7831]

The sheer number of people that'll buy transmissions or new heads and gaskets every 50k+ miles lmaoo. you choose what you like and deal with there known issues.

[@misterspot1552]

Bubble

[@ec7945]

What if you have none of those symptoms but a very very hard to see haze at idle?

[@Duramaxtuner]

Injectors may have bad balance rate.

[@ec7945]

@@Duramaxtuner any way to correct it?

[@mikekopisz1227]

Fuel additives and doing the Caterpillar fuel filter mods and nothing,but top-tier fuel will help these injectors last FOREVER.....biggest issue is caused by US diesel caused by EPA regulations...and due to the fact,that these parts are primarily designed in the UK,they are tested with UK fuel,which has a ton more lubricant in its fuel(more sulfer).....I actually recommend adding fuel additives to any diesel...whether it's a common rail,a HUEI or even an old school mechanical...being seeing a lot of common rails' having pump failures lately...and its because of the fuel...and it's always the roller bearing on the piston tappets (lifters)... basically, completely trashes the entire fuel system....I have Deutz 2.9 with a single piston,I'm working on right now.Metal EVERYWEAR...I'm not even going to bother rebuilding the injectors,cause of scoring..So,Yeah...if you own ANYTHING with a diesel...start adding additives!!... Great video👍

[@justinbouy3153]

My duramax is surging at idle do you think it's more likely injectors or fuel pressure regulator?

[@justinbouy3153]

It's an lb7

[@Duramaxtuner]

@@justinbouy3153 check your fuel pressure regulator

[@terryscott7563]

Wow

[@1979gmcummmins]

Interesting. The older injectors such as 12 valve this didn't happen

[@Duramaxtuner]

True!

[@Ben-et8wh]

so on my cts2 it says to check when engine is cold at idle, is this true? I find the colder it gets the worse my rates are at startup, give the engine even 1 or 2 minutes to run and the rates go down a lot. and then at proper operating temp they are great. so not sure what to make of all this.

[@Duramaxtuner]

We recommend waiting until the engine is at operating temperature before checking balance rates. If you have any questions, feel free to give us a call 815-568-7920.

[@irredeemabledeplorable5227]

Any reproduction injectors with HARDENED ball seats?

[@MrFred-xb8sm]

Bought a brand new 03 duramax and always had acdelco filters, additive and needed new injectors at 36k miles. At 100k another one failed and kept pouring fuel washing a cylinder, destroying itself.

[@Duramaxtuner]

Sorry to hear about that.

[@DougDimadome]

Welp looks like im not buying the lb7

[@Romans--bo7br]

Matthew Stewart.... I have a 2002 LB7..... and changed mine with NEW Upgraded Bosch injectors, with 256,578 miles on the Original injectors, and only ONE of the Original injectors was starting to have balance rate values of around -2.4 to +3, and now at 302,157 miles I just changed the FPR (Fuel Pressure Regulator) a few weeks ago as it was starting to sporadically cause the engine to do quick surges at idle.... the pump is still Original as is EVERYTHING else and I have Zero leaks, weeps or any other issues from the radiator to the rear end.

[@nou8257]

Your biggest issue was prob that stock filter system

[@williamsantiago7303]

Hey buddy my name is William🤝, great video and VERY INFORMATIVE. Maybe you could help me, I have a Ford F250 pick up truck 2011 powerstroke 6.7l that I bought new back then. I take VERY GOOD CARE of it but in 2019 I retired the truck and it just sits in the driveway and it's got 113,000 EASY GRANDMA miles, never dogged it out and oil and filters have ALWAYS been changed on time. I always keep it with a full tank. Well every 3 months or so I'll drive it to work for a week and then park it for another 3 to 4 months or longer and that went on for 2 years. Here lately I too have that grayish white smoke you're talking about in the video. Before I retired it on March of 2019 I had a new fuel filter put in it because I wanted to retire it with a new one, so that new filter I just took it out this weekend after just sitting and it looked pretty bad so could that filter be partly the problem with this smoke and it only happens at idle. The truck ran PERFECT before retirement. A truck with these miles and history, do you think I might be looking on replacing a injector or could I maybe try pouring a diesel cleaner in my new filter chamber and run it to see if it was just cleaning needed? Anything suggestions I would really appreciate it. Sorry this was so long friend. 🤝

[@Duramaxtuner]

I would look into the CP4 high pressure pump. Can it keep up with peak rail pressure demand? Check the mProp screen and see if it has any debris.

[@williamsantiago7303]

@@Duramaxtuner Hey buddy, thank you for the fast reply and the info. I will try to look into what you said. 👍

[@mikelime514]

I’m an LB7 owner been there done that!!! 😂

[@Duramaxtuner]

Sorry to hear that.

[@mikelime514]

Duramaxtuner It’s all good. I love the LB7 but sometimes I wish it was an LLY for a few different reasons.

[@Bradygoodz]

Additive additive maintenance and additive, fresh filters and additive. Period. It should be mandatory for any lb7 owner at this point in the game. Ulsd is garbage. How hard is it to keep the injectors lubed. It's kind of the EPA's fault that we have to perform this weekly pump ritual...Been preaching it for years.. tcw3 and power service mixed. I'm gunna make fuel tank door stickers, "shitters full". Market that shit and sell the hell out of it.

[@white24valve]

NorthTexasFarming haven't ever used 2 cycle oil in Duramax..always ran it in my Cummins trucks...and have always changed oil and fuel filters 3 to 5,000 miles..cheap insurance to me..my 02 LB7 has 339,300ish miles.. absolutely love it!

[@ParkerBeast1999]

NorthTexasFarming explain your weekly ritual to me in detail

[@Jacobtaylor1775]

@@white24valve How is the ole girl doing a year down the road? Mine is about to roll 250K and want to keep her going.

[@white24valve]

@@Jacobtaylor1775 doing good..rolled 357,000 miles the other day!!

[@Jacobtaylor1775]

@@white24valve That's awesome! I'm actually replacing my front end steering bushings, ball joints, tie rods/ ends, and all that stuff.

[@jorgeigualt7162]

My Silverado 2006 with a Duramax has 540.000 miles .except for thermostats and glow plugs engine has never been touch.has original injectors. And get 19.3 miles p/g average between city and hwy.and is always with a load.This coming Wednesday is going into a shop for first time.I accelerated hard when I was going 55 mph.and engine became on limp mode and check engine light came on. Next day engine was checked and showed Code P0087

[@Duramaxtuner]

Start with a Race Plug, but it could be a low pressure side supply issue or it could be a CP3.

[@acres90]

So, stay away from an '03 duramax with 145k??

[@acres90]

@MegaStick93 yeah i hear ya...it looked like a brand new pickup. But the asshole used car lot sold of before I could go look at it

[@turtlezed]

thats the thing, how are you gonna know what life its had? probably an edge to check the balance would be a good idea if going to look at one of these ....how much are they?.....and thats the beginning of the shelling out ........, ive read some stories on here, youre gonna need a second mortgage to keep one on the road....

[@GIGABACHI]

Injectors under valve covers on an engine jammed into a toy truck engine compartment . . . not so brilliant. F-THAT. One of the few reasons I HATE WORKING on over the road diesels. Does the I-6 6.7L Cummins have the same setup ?

[@isaacrecord6162]

JIGA BACHI yeah it’s under the valve cover but they’re super simple to get to

[@buffalodiesel1809]

cummins injectors are … under a cover.... the 6.5 chevy diesel's injectors are out in plain sight... no cover to remove Ford injectors are also under cover.....

[@randyhughes5160]

What crap.use a torque wrench but no one gives the torque for the hard line

[@DuncanMargetts]

Two stroke oil.. cheap lubricity. 200:1 mix

[@white24valve]

No Cetane in 2 cycle oil...when I was a Cummins owner..used lots of that stuff

[@nickcrane8329]

www.fuelexpert.co.za/2-stroke-oil-in-diesel-technical-study.php read this and you'll change your mind

[@cdsmit27]

How does that compare to Lucas upper cylinder lubricant?

[@jadebylund7061]

The main reason I won't ever modify my diesel truck. Injectors fail bad enough on their own and are so expensive to replace. Honestly modern diesels are less reliable today mainly because of the finicky injectors on new trucks

[@rhunter3406]

The cp4 on the fords and chevies cause total fuel system failure. Had it happen to 2 lmls where I work. 15000 EACH!

[@turtlezed]

kindof makes you wonder why anybody would want to own a diesel engined vehicle....the days of diesel are numbered and it will be resigned back to commercial use only one day and all passenger cars will be petrol/hybrid or electric....or we'll all be riding bikes.....pedal bikes not motorbikes....

[@tommyt2854]

@@turtlezed wouldn't hurt my feelings if we went back to horses! Seriously though, I agree. Maybe not our lifetime, but.....

[@wazza33racer]

Dont get diesel fuel when a tanker trailer is unloading at a gas station.........the gravity unload is still able to stir up and disturb the water and sediment in the bottom of the storage tanks and if you are getting diesel from a bowser at the same time, you will get water in your tank. Even OEM filters have a rated efficiency at so many microns at 60%........so you will need at least 2x 2 micron filters in series to have acceptable filtration at 2 micron and change them often.

[@shawnp8429]

I bought a brand new 2020 in 2021 all they had because virus.. this Denali 3500 HD is nothing but a problem and has been in the shop as much as the road..50k miles and overheating, Radio not working. Injectors twice now, Exhaust heater went bad and its non stop problems.. GM will not buy this 97k dollar problem back.. I got screwed big time buying this truck.

[@Duramaxtuner]

Sorry to hear that.

[@whocaresaboutme29]

What about a 2 micron fuel filter water separator??? Uh the factory filter just sucks ass.it causes the damage..period..!! Gm got sued by sum money hungry lawyers in 05.and gm lost..had to upgrade a pos fuel filter that made them millions in injector repairs..had to give a free filter to all duramax owners..upgrade to a tandem fuel filter..

[@johnameil3411]

One option would be to sell the truck and buy a Cummins and spend the money saved on ammo,

[@nathanmarzolf9596]

John Ameil until you have to spend even more money on a dodge tranny and new front end. Now if you put a cummins into a chev or Ford that would be a good truck

[@johnraymond5817]

Money saved ? A new transmission every year and front end every other year. Lol

[@nou8257]

Only if you buy a manual transmission Cummins auto's are a joke

[@tommyt2854]

@@dustygadsby522 lol! Put a smile on my face; I can't wait to get back to work and call someone a "penis wrinkle"!!

[@aldenrichie]

Cubic millimeters? Lol

[@Duramaxtuner]

LOL?

[@aldenrichie]

Duramaxtuner just giving yall a hard time about calling it "MM3"

[@Duramaxtuner]

Thanks for reaching out - appreciate hearing from you - even though you want to give us a hard time. LOL.

[@PHOTOGRASPER]

What a shitty company. Definitely my last Chevy ever.