How JustAnswer Works:
  • Ask an Expert
    Experts are full of valuable knowledge and are ready to help with any question. Credentials confirmed by a Fortune 500 verification firm.
  • Get a Professional Answer
    Via email, text message, or notification as you wait on our site.
    Ask follow up questions if you need to.
  • 100% Satisfaction Guarantee
    Rate the answer you receive.
Ask Matt Your Own Question
Matt, Engineer
Category: Car
Satisfied Customers: 20368
Experience:  Honors degree in Mechanical Engineering, worked 8 years as a Formula 1 engine engineer.
Type Your Car Question Here...
Matt is online now
A new question is answered every 9 seconds

Isuzu truck NPR hd diesel: I have a 2007 Isuzu diesel NPR hd

This answer was rated:

I have a 2007 Isuzu diesel NPR hd truck, 70,000 miles. Very hard to start, must manually push priming button on top of fuel filter assembly to start. Once started will idle and run moderate power acts like air or bad fuel. No air in system, fuel inj cleaner added and replaced filter twice. Is there a possibility if bad wiring of bottom of fuel separator in filter?

sounds like it may have developed an air leak on the fuel supply pipe from the tank to the engine. The engine has no separate lift pump and relies on the built in one in the injection pump. If a leak has developed on the fuel suction pipe then air entering the system will air lock the pump.

Try pumping up the fuel using the hand pump in the engine bay on the filter housing, then crack off / loosen each injector pipe in turn while cranking the engine and getting an assistant to operate the primer. This will expel air from the injection side and the engine should fire up. The problem will be cured by checking the supply pipe along its length for signs of leakage and repairing any you find.

If you daub each pipe joint with heavy grease and the issue goes away then wipe the grease away one at a time to highlight the problem joint

Matt and 6 other Car Specialists are ready to help you

Related Car Questions