Irratic Duramax Behavior

[Shawn T]

I currently own the truck in the sig. 06 LBZ duramax. I have had a couple minor issues:

 

1. Got some bad fuel and now have an ugly fuel knock, especially when cold.

a. Tech checked rail and injector pressures, would have to start parts-changing to try and find the noisy injector, so just living with it.

 

2. Every now and then, when I stomp on it, complete loss of power until I let up and feather it. Has only happened about half a dozen times. Changed the fuel filter hoping that would fix it and it happend 1000 miles later. wierd?

 

3. When the temps here reach in the mid 90's and up the fuel filter just hemorages fuel out of the water drain and it usually takes about 5 seconds on the starter to fire it up. Filter is relatively new, about 5000 miles on it.

 

4. I have a Dynamax free flow muffler with CAT removed. Everytime I pull a trailer and tax the motor a little, I get an SES light. After about a day of normal, no load, driving it disappears.

 

Any thoughts on these minor issues? Please help, nothing can ever be duplicated at the dealer and I'm tired of paying deductables.

[Shawn T]

I currently own the truck in the sig. 06 LBZ duramax. I have had a couple minor issues:

 

1. Got some bad fuel and now have an ugly fuel knock, especially when cold.

a. Tech checked rail and injector pressures, would have to start parts-changing to try and find the noisy injector, so just living with it.

 

2. Every now and then, when I stomp on it, complete loss of power until I let up and feather it. Has only happened about half a dozen times. Changed the fuel filter hoping that would fix it and it happend 1000 miles later. wierd?

 

3. When the temps here reach in the mid 90's and up the fuel filter just hemorages fuel out of the water drain and it usually takes about 5 seconds on the starter to fire it up. Filter is relatively new, about 5000 miles on it.

 

4. I have a Dynamax free flow muffler with CAT removed. Everytime I pull a trailer and tax the motor a little, I get an SES light. After about a day of normal, no load, driving it disappears.

 

Any thoughts on these minor issues? Please help, nothing can ever be duplicated at the dealer and I'm tired of paying deductables.

 

anyone? Please some advice, I'm stumped

[gmtech4]

its not hard to find a bad injector with a tech 2 scanner ,so they are full of it ,

 

you also have a code that has to be scanned and diag'd by an experienced dirtymax tech,they work for a GM dealer or a good diesel shop

 

sorry but that's what needs to be done ,you may be eligible for a dirtymax warranty

 

and you have extended warranty .leave it there 'till its fixed

[Shawn T]

its not hard to find a bad injector with a tech 2 scanner ,so they are full of it ,

 

you also have a code that has to be scanned and diag'd by an experienced dirtymax tech,they work for a GM dealer or a good diesel shop

 

sorry but that's what needs to be done ,you may be eligible for a dirtymax warranty

 

and you have extended warranty .leave it there 'till its fixed

 

Stil under warranty. So get this. I borrowed a scanner tonight and hooked it up using the diagnostics. I ran the fuel rail pressure actual vs. expected and when I would hammer on it, expected values would climb to about 12,000 psi, actual would follow and then crash! The actual would just crater down to about 3500 psi and the truck would just fall flat on it's face. This has been going on for about 8 months now. I finally just had to take matters into my own hands. I did this a number of times until finally the SES light came on and the truck went into an almost powerless mode. I limped it home and pulled the code. 0087 fuel rail pressure too low. I had to reset it because it would barely move. Looking back I guess I should have left the code failed because I am pretty sure I will get the "cannot duplicate" excuse.

 

Bad injector?

Bad injector pump?

This started occuring and I immediately changed my fuel filter and it did not remedy it. Anyway, I can imagine a clogged filter inhibiting fuel flow but not just cutting it off all together when under hard acceleration. I really started to tell when the allison tranny started to shift horribly.

 

I'm frustrated as hell. I'm going in tomorrow first thing to see if I can duplicate it. I have tried and never been able to. But this truck definately has a serious issue. Any suggestions what the problem is so I can throw it at the mechanic to have him check?