Chevy/GMC Duramax 01-04 LB7 Discussion of Chevy and GMC Trucks with LB7 Duramax Turbo Diesel Engines

Replacing Duramax LB7 Injectors 01-04 tips and hints

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  #111  
Old 03-25-2011, 05:52 PM
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it could also be a loose line or air getting into the system. like your thinking. did you prime up the fuel system till the pump got impossible to prime?
 
  #112  
Old 03-26-2011, 02:16 AM
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Yeah - I went back after work and re-primed and pumped it up and tried to start it, but no luck and no increase in FP.

I thought it might be the line from the filter housing to the pump(?), so I replaced that - no luck

I tried re-seating the filter, but no luck.

When I pulled the bleed screw again and re-primed, I started pulling bubbles through. - when I closed the screw, re-primed and opened again I got more air.

Im pretty sure Ive just killed my priming pump, cause now its leaking.
 
  #113  
Old 03-26-2011, 04:51 AM
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Originally Posted by RandomGuy
Yeah - I went back after work and re-primed and pumped it up and tried to start it, but no luck and no increase in FP.

I thought it might be the line from the filter housing to the pump(?), so I replaced that - no luck

I tried re-seating the filter, but no luck.

When I pulled the bleed screw again and re-primed, I started pulling bubbles through. - when I closed the screw, re-primed and opened again I got more air.

Im pretty sure Ive just killed my priming pump, cause now its leaking.

the filter housing cracking can happen, and does keep the truck from starting, they offer rebil kits for them at the dealer.
 
  #114  
Old 03-29-2011, 09:57 PM
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Heavy duty, put a wrap on the job and the truck is running nice. Many thanks for the write up. It needed a lot less special tools than I suspected. The Injector puller was a slight hold up but I was lucky to meet up with Bobby, of Bobbies diesel injection, Florence SC. What a super guy to talk to, and was glad to have his ear as I worked the job, and he loaned me the injector puller. All is back together, running like a watch, and I think I may be back to the 19mpg mark.
My truck is a yankee truck and was driven in the salt for 5 years, most of the allens were pretty nasty, and spent extra time making sure I did not bugger the heads on the pulloff. Drivers side was very tight especially back by the firewall. So tight made a 5mm allen socket by cutting off a old 5mm and using a 1/4 drive socket wrench to get into the tight spaces.
I kept telling myself to take pics but only got one on each side as the valve covers came off.
Although it took a few weekends, it was nice as many of my students never thought of me as mechanically inclined (math teacher), so that has been fun to have as a side conversation with them.
take care all, probably till the next project.
riegej23
 
  #115  
Old 04-07-2011, 10:58 AM
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Im back and I think Im just about to the monkeys with tools phase.

I couldnt find a dealer rebuild kit, but I did find a guy here on the other side of town that was selling biodiesel rebuild kits. - I got that over the weekend and just tried to fire things up again this morning.

One of the things the guy pointed out to me while we were talking was the valve next to the alternator that lets you burp the fuel system. He said the dealer uses it to suck the air out, which sounds like a great idea, except I had no means to do it.

I installed the new o-rings, put it back together and installed it on the truck. - The fuel system primed up fine and after some cranking and playing with the schrader(sp?) valve next to the alternator, the fuel pressure started to come up.

I kept priming and burping and eventually the pressure hit as high as 1643psi, but the truck never started. At that point I think the o-ring went south again. The pressure had been staying high, but now it dropped back down to the 2-300psi level.

What kind of fitting is this? Can I vacuum the fuel system myself? I have one more rebuild kit and feel like Ive gained a little ground, but want to plan my next move a little.

---AutoMerged DoublePost---

Plan, Schman.

I rebuilt the pump at lunch and then with the help of a neighbor, I primed up the fuel system and now the pressure gets up past 7xxxpsi. It still drops back down when the engine isnt cranking, should it hold pressure?

It coughed for a second like it might start, but failed to with another 15 seconds of cranking.

Im putting a charge back in the batteries and then Ill be ready to try again.

I notice that the balancing flow rate on 3,4 and 8 are at min (-512) value. Should I be worried about that? Anything else I should be checking?

---AutoMerged DoublePost---

Im getting foam at the bleed screw again. - It primed up just fine. No foam. Per efilive, the fp was over 7k at some point, so I should have enough fuel pressure. Pressure drops back to 200-300 psi within 60 seconds (I never paid attention this before, so I dont know if the rail should maintain pressure).

After 5-6 attempts to start and screwing with it, I'm pulling air at the bleed screw again though.
 

Last edited by RandomGuy; 04-07-2011 at 10:58 AM. Reason: Automerged Doublepost
  #116  
Old 04-07-2011, 07:51 PM
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is your bleed screw damaged in anyway?
 
  #117  
Old 04-12-2011, 02:00 AM
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Default valve adjustment?

hey im new to the forum awesome right up 2500hd. ill be using it for my injector change on my 03. just wondering if you have to take rocker arms off? couple guys at work claim you do? and also was gonna buy injectors from a company called lincoln disel specialities was wondering if any one heard of them or had any experience with them? any help is appreciated.
 
  #118  
Old 04-12-2011, 06:32 AM
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no you dont need to, you can fit a pry bar under then to pry the injector out
 
  #119  
Old 04-12-2011, 06:19 PM
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ok thankx.
 
  #120  
Old 04-18-2011, 06:35 PM
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Correct, The rocker arms can stay on.

I work for Lincoln Diesel so my opinion might be biased, but 90% of our customers come from Diesel Place: Chevrolet and GMC Diesel Truck Forums so you might get a bit more feedback on there.

Good Luck with the job!

- Titus
 



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