LMM sluggish/smokey once hot at 2000rpm

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DuraRI

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Aug 9, 2018
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Rhode Island
Hey guys, figured I ask you guys for some help. A little back ground I am a diesel mechanic by trade and have built a few duramaxs and I am pretty familiar with them. However my latest build/truck has me a bit lost.

I bought a 2010 LMM that had a bad motor, I had a freshly completely rebuilt LB& so I figured I would utilize the bottom end of the LB7 for the 2010 truck. Heads for the LMM where sent out and completely redone. Block is studded and has an LML oil pump. I removed all the egr/DPF equipment, and put in Bosch reman injectors with 30 over nozzles. topped it off with a freshly rebuilt and upgraded (Fingers vanes, billet comp wheel, 10 blade turbine, ported housing) LLY turbo. Got it tuned from a reputable tuner (not today EPA).

Truck idles smooth, has decent power and no smoke when first driving. However once it warms up it will start to "hold back" as i ease into the throttle...around 1800-2000rpms it will puff some white smoke and chug...if i push the throttle more it pushes through and clears up and takes off. Rail pressures are good....desired and actual are right on par with each other. MAF seems to be doing what it should ( I did clean it as a hail mary fix) as well. MAP sensor is reading boost (maxes out around 89in HG). Has new filters (CAT). Full disclosure I havent installed my pick up tube and lift pump on to the truck, but as I am not seeing a rail pressure drop I am skeptical it will fix it (I am going to put it on in the near future). I am leaning towards maybe a boost leak??? Any thoughts or experience would be greatly appreciated!

whew...sorry for the long post...wanted to give as much detail as I could.
 
Bdsankey

Bdsankey

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DuraRI said:
Hey guys, figured I ask you guys for some help. A little back ground I am a diesel mechanic by trade and have built a few duramaxs and I am pretty familiar with them. However my latest build/truck has me a bit lost.

I bought a 2010 LMM that had a bad motor, I had a freshly completely rebuilt LB& so I figured I would utilize the bottom end of the LB7 for the 2010 truck. Heads for the LMM where sent out and completely redone. Block is studded and has an LML oil pump. I removed all the egr/DPF equipment, and put in Bosch reman injectors with 30 over nozzles. topped it off with a freshly rebuilt and upgraded (Fingers vanes, billet comp wheel, 10 blade turbine, ported housing) LLY turbo. Got it tuned from a reputable tuner (not today EPA).

Truck idles smooth, has decent power and no smoke when first driving. However once it warms up it will start to "hold back" as i ease into the throttle...around 1800-2000rpms it will puff some white smoke and chug...if i push the throttle more it pushes through and clears up and takes off. Rail pressures are good....desired and actual are right on par with each other. MAF seems to be doing what it should ( I did clean it as a hail mary fix) as well. MAP sensor is reading boost (maxes out around 89in HG). Has new filters (CAT). Full disclosure I havent installed my pick up tube and lift pump on to the truck, but as I am not seeing a rail pressure drop I am skeptical it will fix it (I am going to put it on in the near future). I am leaning towards maybe a boost leak??? Any thoughts or experience would be greatly appreciated!

whew...sorry for the long post...wanted to give as much detail as I could.
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Did you put the LBZ/LMM reluctor wheel on? Any codes?
 
D

DuraRI

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Aug 9, 2018
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Rhode Island
I haven't, not a bad idea, I may contact them and see if they're willing to weigh in . It did it on the stock tune as well as the custom tune though.
 
Bdsankey

Bdsankey

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DuraRI said:
I haven't, not a bad idea, I may contact them and see if they're willing to weigh in . It did it on the stock tune as well as the custom tune though.
Click to expand...

They will be able to point you in the right direction. Regardless you'll have to take a datalog or some type of further info for us to help diagnose it.
 
Bdsankey

Bdsankey

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DuraRI said:
They are Bosch remain......from pensacola... :eek::mad:
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ZeroGravity58 said:
Swap injectors to good injectors. I don't understand why everyone still buys from this place. They are cheap for a reason.
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BINGO! I cannot stress enough how important it is to buy ONLY from someone with a good reputation and a passing mark from Bosch. I don't have enough fingers and toes to count the amount of times I've replaced bad injectors from Pensacola Diesel due to a customer being cheap and installing them themselves. If a customer wants my shop to install injectors and won't let me source them I won't do the job as I don't want my name tied to crap quality products.
 
Bdsankey

Bdsankey

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DuraRI said:
what does everyone recommend for injector dealers? I like to be certain this is the issue before buying new ones.
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Any of our site sponsors can get you setup with a quality injector. LDS is the largest site sponsor in terms of injectors, give Brent a call.
 
D

DuraRI

New member
Aug 9, 2018
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Rhode Island
Bdsankey said:
Any of our site sponsors can get you setup with a quality injector. LDS is the largest site sponsor in terms of injectors, give Brent a call.
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I will. I still like to be sure that is in fact the problem first. I rather not spend $4k and still have an issue. I am going to log some data on it tonight and see what the tuner has to say. I can post it here as well if anyone cares to look at it.
 
gmduramax

gmduramax

Shits broke
Jun 12, 2008
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Nor cal
DuraRI said:
I will. I still like to be sure that is in fact the problem first. I rather not spend $4k and still have an issue. I am going to log some data on it tonight and see what the tuner has to say. I can post it here as well if anyone cares to look at it.
Click to expand...

It’s the injectors 30% is tiny and will run on the stock tune just fine. Hopefully you can return the ones you have.
 
juddski88

juddski88

Freedom Diesel
Jul 1, 2008
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Chesterfield, Mass.
I'm not sure there is enough data here to jump on the bad injector train. Nobody asked if the truck is making a big change in fuel quantity when this starts to happen, or pulsewidth, or timing, or what the desired vs actual vane position is doing. These are all relevant variables. A crap turbo will even feel sluggish and cause excess smoke.
 
gmduramax

gmduramax

Shits broke
Jun 12, 2008
4,048
231
63
Nor cal
juddski88 said:
I'm not sure there is enough data here to jump on the bad injector train. Nobody asked if the truck is making a big change in fuel quantity when this starts to happen, or pulsewidth, or timing, or what the desired vs actual vane position is doing. These are all relevant variables. A crap turbo will even feel sluggish and cause excess smoke.
Click to expand...

“Once it warms up it puffs white smoke” nothing will cause white smoke except injectors
 
juddski88

juddski88

Freedom Diesel
Jul 1, 2008
4,655
119
63
Chesterfield, Mass.
Weird, maybe I'm the only one who has had white smoke from a broken piston, bent rod, or a bad turbo. But in this case he said it clears up, which I would not expect from a whole set of crap injectors, which is why I think more data is needed
 
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