Another Duramax down

[02greysixer]

Well, truck is broke and it's broke good. Went on a trip last night to visit a friend and concert about 200 miles from my house, truck ran great on the way down. I even behaved myself and went the speed limit the whole time and never turned the motor over about 2300 rpm. Went to leave the concert to head home, truck took a little longer to start then usual but didn't think anything of it. Well then it started skipping a little, kind of like turning the key off and on really really fast. It did this and got progressively worse the whole way home. Got up and decided to change the fuel filter, it took forever to start this time. But when it started it seemed better so I took it for a drive, that's when it happened. I took off and shifted 2nd to 3rd at about 2300 rpm, still had a little skip but not as bad. Then I got back on the gas and the boost gauge started going crazy, and the motor went to rattling and skipping like crazy. Also started blue/white smoking. No check engine light and all the gauges read normal. (60psi oil pressure, about 160* on temp guage) any ideas what happened??


Sint frum tha orijinul smert fone

 

[coldLBZ]

Does it smoke out of the oil fill cap when running?

 

[JMDuramaxLB7]

Sounds like you may have hung a injector open. I had one stick and it rattled, smoked and missed just like you described. Mine also had no check engine light and all gauges read normal. Good luck and keep us updated. Alaso don't run it more than you have too. A hung injector will melt a piston real quick.

 

[02greysixer]

Does it smoke out of the oil fill cap when running?

Don't know, I will go check that out.

And would a hung injector cause the boost gauge to bounce from like 10-20 real quick?


Sint frum tha orijinul smert fone

 

[xcablb7]

boost reading is prob all over from erratic fueling

 

[Kspen90]

Damn i hope its just an injector buddy

 

[SSchmi5519]

Return the truck to stock tuning. Report.

 

[fishsmith]

I have a lmm in the shop doing just about the same thing.


Sent from my iPhone using Tapatalk

 

[02greysixer]

I am relatively sure it's an injector issue. The smoke smells like unburned diesel fuel and there's no blow by coming through the oil cap. I forgot to say I dropped the tune down to the 65 horsepower setting because the truck seemed louder than it was before. Just returned it to stock, still loud, shaking and smoking grey at idle. Clears up when revved. I just returned it to stock and still doing same thing. Guess I'll start researching injectors


Sint frum tha orijinul smert fone

 

[SmokeShow]

You just reported that you tried running some 2 stroke oil didn't you?

If so, that could be something to do with it because it sorta flushes the fuel system out. So any build up in places may have been broken free & caused a hang up in your injector?


Sorry to hear you're having issues though.

 

[Atouchofgrass]

Sounds like you have an injector issue.

 

[02greysixer]

You just reported that you tried running some 2 stroke oil didn't you?

If so, that could be something to do with it because it sorta flushes the fuel system out. So any build up in places may have been broken free & caused a hang up in your injector?


Sorry to hear you're having issues though.

I just thought of this and was going to ask y'all if that'll happen or not. I bet that's what it was, this truck belonged to a logging company and was his work truck so god knows what kind of fuel he put in it. I'm sure it's had it's fair share of off road run through it and me actually treating it well trying to clean it up has gotten to the injectors . Oh well, guess that's why I only paid about 1/2 blue book value for it. Is it ok to drive to the dealership? I don't have the ability to check which injector is bad. Dealership is about 30 miles away.


Sint frum tha orijinul smert fone

 

[Kspen90]

There are lots of members on your area, im sure one of them would check your rates with efi live. Maybe post a thread titled help with your location and im sure someone will reply:thumb:

 

[02greysixer]

A friend of mine owns a shop about 10 miles from my house. He said he's got the ability to find which one it is. Taking it there tomorrow, after I call the dealership that supposedly put 4 new injectors in it about a year ago and verify. If they did replace one side then hopefully it's just the other side went bad and I can get by just doing 4. If not I will probably do all 8 and maybe go with some 40 or 60 over ones


Sint frum tha orijinul smert fone

 

[Kspen90]

A friend of mine owns a shop about 10 miles from my house. He said he's got the ability to find which one it is. Taking it there tomorrow, after I call the dealership that supposedly put 4 new injectors in it about a year ago and verify. If they did replace one side then hopefully it's just the other side went bad and I can get by just doing 4. If not I will probably do all 8 and maybe go with some 40 or 60 over ones


Sint frum tha orijinul smert fone

I wouldnt go with 40% overs unless you have the money for efi live now, knowing what i know now i would have gone back stock when i did mine. Over 800hp has been made with stock injectors and intake. Once you go with bigger injectors standard tuners and chips no longer work correctly and efi live tuning costs more. If i were you i would put that extra money towards a clutch. Just my $0.02

 

[616samuel]

it's an lb7, they are widely known to throw injectors. could be one of the older 4, could be one or more of the new 4 as well... never know which one will want to go next

sorry about your luck!

 

[Kspen90]

Have you ran it low on fuel recently?

 

[JustinD]

Mine sounded like that when it hung an injector open too.

 

[02greysixer]

I wouldnt go with 40% overs unless you have the money for efi live now, knowing what i know now i would have gone back stock when i did mine. Over 800hp has been made with stock injectors and intake. Once you go with bigger injectors standard tuners and chips no longer work correctly and efi live tuning costs more. If i were you i would put that extra money towards a clutch. Just my $0.02

Good point, probably just stick with stock parts for now. I know that clutch isn't going to last forever.

And I did run it low on fuel a few times. I was rushing all over hells half acre last week and low fuel light came on 2 or 3 times before I could get to my gas station. Me and my dad have always used the same station and he's never had a problem. It's a sunoco truck stop and they're about 10-15 cents cheaper than every other place in town so I don't like filling up anywhere else if I can avoid it.


Sint frum tha orijinul smert fone

 

[MACKIN]

You just reported that you tried running some 2 stroke oil didn't you?

If so, that could be something to do with it because it sorta flushes the fuel system out. So any build up in places may have been broken free & caused a hang up in your injector?


Sorry to hear you're having issues though.

Hmmm Why do you think that about the 2-stroke oil? Is there any validity to that or just a assumption?