new member post

thebruce

New Recruit
Owner/Operator
Hello to all.
I just joined this forum hoping to find a sounding board (and some advice) on how to repair my old 2004 diesel Isuzu NPR-HD box truck. I've had it for 5 years and 40K miles (135K total as of today) and this is the first time it has broken down. Apologies for the cross post and thanks for the repost tip. I followed a thread from another board to get here.
I think my problem is fairly simple. It began by overflowing the fuel filter. I have replaced it but cannot seem to get the lines bled. (no it does not have a hand pump). I am getting fuel to the filter but not to the injectors (I cracked all 4 of them but no fuel). The vacuum assist cutoff appears to be wokling when I roll the key and I think I can hear the electric fuel lift pump.
My off-year manual doesn't exactly match the truck but mentions a bleeding process that includes a return line from the injector pump.
My thinking is that I need to bleed the air out of the lines but after several attempts to mechanically pump to the injectors (with the starter) absolutely no fuel come thru. This makes me think the cutoff valve isn't opening or the line to the injector pump is blocked (or the injector pump is bad).
If this was my tractor I might spray diesel into the air intake but I'm not sure I should atomize fuel into the turbo.
Anyone feel like chiming in to correct my thinking.
Thanks in advance.
thebruce
 
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Hino123

Expert Expediter
Researching
No electric fuel pump, and the vacuum pump runs off the back of the alternator. Remove the inlet to the fuel pump, install a test line directly into a separate container of fuel, (or tou can run it in the tank if you have the saddle tank) crank the truck over and verify it is sucking fuel, then crack one fuel line only slightly to purge any air. If it still will not run you have an issue with the high pressure pump forward, if it does run you have an issue on the low pressure suction side of the system. It is basically splitting your fuel system in half to isolate the issue. I never recommend starting fluid but as a last resort. Make sure the glow plugs are disconnected if you go that route. Good luck and let us know how you make out.
 

Hino123

Expert Expediter
Researching
The 2004 manual states you DO have a hand primer. See the attached bleed procedure. If this is not the fuel configuration on your engine then it is not a 2004.
 

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