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Chris (aka-Moose)
Chris (aka-Moose), Technician
Category: Chevy
Satisfied Customers: 47631
Experience:  16 years of experience
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Hal, I am also a master tech with no experience on the

Customer Question

hello Hal, I am also a master tech with no experience on the durmax lb7. I bought one drove it a month went to the store came out and it would not start. After doing much research I finally figured out I had zero pressure from the injector pump. I took it off and found some debri that looked like a fiber seat in the overflow valve. Thinking that was it i bought another overflow valve, installed it and started getting 60 lbs of pressure. I found the pump is supposed to put out around 400lbs while cranking. I searched for information and felt that the piston pump for some reason was not pumping. While diagnosing on the bench I managed to break the driven gear. I found a used pump with gear for close to the same price as the gear and bought it. I tested it and it put out the higher pressure. I put in on the truck and it fired up. I put everything back together and ran it a few times, let it sit overnight to make sure it did not loose prime and it started this morning. after startinga few times I ran it for about 45 minutes sitting then let it sit a while. Went to start it again and no start. There is no pressure coming from the pump, measuring it from the high pressure pump outlet (same as first pump). To have the same problem with a completely different pump suggests I have not found my problem. I have good flow from the filter/primer. I already put a new pressure regulator on when I first installed the used pump and it was running with the new regulator. What would keep the pressure from going from the gear pump to the piston pump? What am i missing?
Submitted: 1 year ago.
Category: Chevy
Expert:  Chris (aka-Moose) replied 1 year ago.

Welcome, I'm Chris (aka Moose). I normally log in after 3 pm central everyday. Please let me know exactly what you need from this conversation so I can provide EXCELLENT 5 STAR service.

Did you flush all the lines to and from the pump and injectors. These pumps do not like trash. When a pump goes out there is now metal chips in the system and if not removed they too will ruin the new pump.


Once you have selected a rating at the top of your page view for my first answer to grade my assistance. All follow up responses are free and welcomed. Ask me about a phone call if you prefer that service.

Thanks Chris

Expert:  Chris (aka-Moose) replied 1 year ago.

Hello again Chris here,

I am contacting you because the post has not been closed or rated. We have 7 days to get a post rated before it times out. When a post times out, that means its no longer on my active list (if you reply I never know it.) You have already paid the fees to get this question answered, but it appears your not pleased, or need more help.

Let me help some more. Is there anything else you feel I could offer so you would be pleased with my help. I have the option to call you if that would be better.