2001 Duramax LB7 Knocking
Re: 2001 Duramax LB7 Knocking
Do you have a Tech2? I believe I can monitor fuel rail pressures and potentially disable one injector at a time to troubleshoot.
Re: 2001 Duramax LB7 Knocking
I guess I’ll call the injector place and see if they can help me diagnose either cp3 or identify the bad injector.
Re: 2001 Duramax LB7 Knocking
I can get my hands on the tech 2 yes but it isn't with me right now. Do you want me to get it?
Re: 2001 Duramax LB7 Knocking
I will get it this Wed.
Re: 2001 Duramax LB7 Knocking
Stopped at Metro Injection Service this morning. They plugged in a Tech 2 and dropped out selective cylinders. Less-notable-idle lope/drop when dropping cylinder 4 than all others.
Injector balance rates showed cylinder 4 was "different". Still in-spec as less than 5% per the technician at Metro, but he was suspicious of it anyhow because of the idle drop.
He checked commanded vs. measured rail pressure and thought all was good there.
They tossed me a new injector (I expected to need to buy it and get credited once I brought the old one back) and sent me on my way. I also snagged a driver's side heat shield that they happened to have on the floor and tossed the tech $20 for both the "free" diag and heat shield.
Hopefully swapping just the #4 injector solves it finally. This is exhausting (or was that the manifold?)?
Yes the pics are awful - I didn't want to tie up the technician anymore time since this was kind of a freebie.
Injector balance rates showed cylinder 4 was "different". Still in-spec as less than 5% per the technician at Metro, but he was suspicious of it anyhow because of the idle drop.
He checked commanded vs. measured rail pressure and thought all was good there.
They tossed me a new injector (I expected to need to buy it and get credited once I brought the old one back) and sent me on my way. I also snagged a driver's side heat shield that they happened to have on the floor and tossed the tech $20 for both the "free" diag and heat shield.
Hopefully swapping just the #4 injector solves it finally. This is exhausting (or was that the manifold?)?
Yes the pics are awful - I didn't want to tie up the technician anymore time since this was kind of a freebie.
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Re: 2001 Duramax LB7 Knocking
I don't know that you would have gotten a free injector so easily if you just brought Tech 2 pictures. So I guess that's something.
Re: 2001 Duramax LB7 Knocking
Yeah - I would’ve had to drive there to get the injector anyhow, so very little extra time spent and I had a “free” consult.
Re: 2001 Duramax LB7 Knocking
I guess I will still borrow the tool and you can use it to verify repair. Definitely would have been nice to get a before shot on balance...
You could always reinstall the old ones.
You could always reinstall the old ones.
Re: 2001 Duramax LB7 Knocking
Replaced injector 4 last night. Found a hunk of crap - hard like a small rock or hunk of corrosion in the injector inlet. Haven't test fired yet.
Re: 2001 Duramax LB7 Knocking
That's pretty wild. And concerning.