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2001 Chevy Silverado 2500HD 4x4
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Discussion Starter · #1 ·
Hey guys new to Duramax’s (use to 7.3 powerstrokes lol), and new to the site. I’m chasing a possible injector problem on my truck. I bought it about a week ago. If they need replaced I’ll do so but I don’t want to spend that kind of money if it’s not the problem. I’ve got a friend that is the service manager at my local GMC Cadillac dealership so we hooked it to their Maxxis. I am adding a screenshot of what we found. If you guys could give me some insight on what you see it would be greatly appreciated. The truck smokes at idle. If there’s fuel in the oil it isn’t “obvious” so I’m not sure there. It is very sluggish and has a surge or “miss” on hard acceleration. Again any help would be appreciated. These readings are at operating temperature and idle
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Everything on your attachment looks fine. You have almost 5000 lbs fuel pressure at idle. You need to do the 'bottle test' aka the fuel injector bypass test. Search the forum for more info on the bottle test. This will tell you if your injectors are bad and need to be replaced.
 

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Yeah, your balance rates look good, but that doesn't tell the complete story. If not for the driveability issues, I'd say your numbers looked good. Can you monitor desired vs. actual rail pressure while you make a few full throttle runs? It's possible the FPRV might be popping off too early, dumping HP fuel to the return system. More common on LLY/LBZ, but still possible. If not, the CP3 might be weak.
 

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2001 Chevy Silverado 2500HD 4x4
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4 Posts
Discussion Starter · #4 ·
Honestly I think I’m going to go ahead and replace the injectors anyway. Called and talked to someone at LDS and I believe that it’s the injectors. Plus it won’t hurt anything to replace them if they’re not bad. The guy I bought it from said the injectors were replaced 30k miles ago but he lied about several other things so I imagine that was a lie too. Also if it’s not the injectors I can at least eliminate that and it’s the most expensive part so there’s that lol
 

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2001 Chevy Silverado 2500HD 4x4
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Discussion Starter · #5 ·
I do appreciate the insight. And if it’s not the injectors I’ll post back and we’ll go from there
 

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Former GM Tech and parts
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The balance rates look good, but balance rates only tell part of the story- a return rate test will tell you if the injectors are returning too much fuel and causing an incorrect fuel dispersal to the cylinder and causing the smoke. Unfortunately the return rate test isn't exactly an easy thing to do, and most of the time people (including myself) bypass that test and just replace the injectors because 95% of the time (if not more) that is the cause. LB7 trucks usually don't have a problem with the rail pressure relief like the LLY/LBZ/LMM trucks. If you monitor the actual vs desired rail pressure and the actual is not keeping up (a few hundred is ok) then the injectors could just be returning too much fuel to keep the pressure up where its supposed to be
 

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2001 Chevy Silverado 2500HD 4x4
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4 Posts
Discussion Starter · #7 ·
Ordered my Bosch reman injectors from LDS. Going to put those in and go from there. I’ll update when I start tearing it apart and what not. I appreciate the help guys
 
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