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I'm working on a 2014 mack mp7. Vin as follows 016738 model…

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I'm working on a 2014...
I'm working on a 2014 mack mp7. Vin as follows 016738 model no gu813. The truck is acts like it I is losing prime and very hard to start. I have to pump it up at primer pump. When it cranks the dpf gets red hot very quickly and the truck starts missing very badly. No engine light. The computer won't connect to ecm. Where do I start??
Submitted: 1 year ago.Category: Medium and Heavy Trucks
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Answered in 2 minutes by:
7/8/2021
Technician: Mike Mcmillan, Shop Foreman/Triage Tech replied 1 year ago
Mike Mcmillan
Mike Mcmillan, Shop Foreman/Triage Tech
Category: Medium and Heavy Trucks
Satisfied Customers: 6,627
Experience: Volvo/Mack Master Tech, Certified with Cummins, Eaton, GM, Hino, Detroit Diesel
Verified

Hello and thank you for using Just Answer. My name is ***** ***** I’d like to try and help. I am sorry that you are having issues with your truck. I know this can be frustrating. Please allow me a few moments to look over your question and I will be right back with you.

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Technician: Mike Mcmillan, Shop Foreman/Triage Tech replied 1 year ago

On your issue, I would check the return in the fuel tank and see if you see air bubbles in the tank while trying to crank the unit and after it starts. I am sure you will. This is an indication that the injector cups are leaking. What happens in the DPF when they leak bad is it allows all the extra fuel to go out of the exhaust and causes the DPF to heat up beyond what it normally is since the ecm can only control the fuel flow from the 7th injector. The injectors will need to be removed and inspected for any damage.

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Customer reply replied 1 year ago
It's only running for a few seconds now but never saw any bubbles
Technician: Mike Mcmillan, Shop Foreman/Triage Tech replied 1 year ago

It will need to be ran usually longer in order to see the air in the unit. Since you have to pump the primer that is an indication of a fuel issue

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Mike Mcmillan
Mike Mcmillan, Shop Foreman/Triage Tech
Category: Medium and Heavy Trucks
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