LBZ Nightmare

Sims

New member
Sep 12, 2020
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2007 Silverado 3500 with LBZ. So far this year I have had replaced under aftermarket warranty.
New....all OEM parts
Fuel pressure relief valve
Fuel pressure regulator
Driver side fuel rail
Fuel filter head
Fuel lines
Injector return lines.
New exhaust manifolds
Cp3
And finally New Turbo
I have had this truck since 39,000 miles and currently has 76,000. It has never been tuned or beat. last night driving home the P0193 code popped up. Does anybody have any advice on this problem please? After all the troubles with this truck this year I’m considering just getting rid of. This all started this year.

Thank You
 
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Sims

New member
Sep 12, 2020
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I’ve known the owner/tech of the shop for years. It just seems like one thing after another with this truck. It all started in January with low fuel pressure and It put me in a limp mode six hours from home.
I was told that the injectors are operating within specs. Would EGR excessive flow trigger fuel pressure sensor code? Truck doesn’t smoke or anything.
 
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gmduramax

Shits broke
Jun 12, 2008
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Nor cal
I’ve known the owner/tech of the shop for years. It just seems like one thing after another with this truck. It all started in January with low fuel pressure and It put me in a limp mode six hours from home.
I was told that the injectors are operating within specs. Would EGR excessive flow trigger fuel pressure sensor code? Truck doesn’t smoke or anything.

Take it to another shop. It’s not the trucks fault it’s not being diagnosed correctly.
 

Sims

New member
Sep 12, 2020
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After reading the forms and talking to a few guys I know I found it hard to believe myself that the CP3 was bad. It was not a catastrophic failure. When it went to the shop it was low fuel pressure. Kept putting me into limp mode and then it kept getting worse. They replaced the fuel pressure relief valve then went to the fuel pressure regulator in a few weeks later they replace to CP3. This drug out for a few weeks because of my warranty company had to send an inspector out before they were OK with the charges. They usually take from 3 to 5 days to get to the shop after you call them. I drove the truck to the shop besides being on limp mode it was running fine no smoke no missing no nothing.
 

2004LB7

Super Moderator
Staff member
Dec 15, 2010
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Norcal
With the right diagnosis, they could have had the right part replaced the first time. I would have checked for air in the lines and performed a return rate test. With that you could get a good idea on what part(s) to replace without doing unnecessary work.

As gmduramax said, take it to another shop that knows what they are doing. You may know your mechanic for years but your mechanic needs more years before he would touch mine truck. Not trying to knock him but it shouldn't be that hard. You may like him but he's making you hate your truck
 

Sims

New member
Sep 12, 2020
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I agree. Makes me sick to my stomach to even look at it in the driveway lol. i’m going to reach out to a few other guys I know around here to see were a good diesel shop is at. Preferably one that has a guy into Duramax Engines.
Thank you for your response.
 

Dallas S

Active member
Jun 17, 2009
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Alberta
Most people will do a balance rate test and claim the injectors are fine... There is more to testing injectors then a simple balance rate check. Just ask if they can provide you with the return rate quantity. We have seen an large increase in high return rates over the past couple years. Time seems to be more of a killer then mileage.

I would be watching fuel supply vacuum, logging the truck and watching DFRP, FRP, and Fuel regulator duty cycle % closely. If the pump pulls vacuum(3-8" HG), and the CP3 pump regulator is going wide open(%5) I would be testing each bank of injectors for high return.
 

Sims

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Sep 12, 2020
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OK I will check into that thank you for your advice I really appreciate it. On a sidenote I drove truck today went on a 2 Hour Rd. trip getting on it every now and then not a spit. Spudder or miss. Ran like a champ. Didn’t even put any smoke out when I put peddle down but the check engine light is still on.