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Discussion Starter #1
Hi all! New member here looking for some help.
I've got a 2006 GMC W4500 (Isuzu NPR) that has developed the infamous p0087 and p0093 diagnostic codes.
p0087: Fuel Rail/System Pressure Too Low
p0093: Fuel System Leak Detected Large Leak
These codes are only triggered under high load such as when going up a hill at 65mph. The truck goes into limp mode when these codes are triggered and has to be power cycled for it to run right again.
This first started about 2 weeks after I changed the fuel filter and so my first thought was I over/undertightened the filter but I bypassed the filter and the codes were still triggered. Some online say to change the suction control valve so that's what I did. However when I put the new SCV in it ran very rough so I put the old SCV back in and it ran smooth (codes are still thrown under load though). Both the new SCV and the old upon taking it back out for inspection have had their inner seal trashed by the place they mate to. In my picture there should be a seal where my finger is pointing to. Does anyone have experience with these?
Sidenote: I ordered a SCV for a Vauxhall Astra or something because it's the same part but cheaper.
GM part#: 98043686
Isuzu part#: 8-98043-686-0
 

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Discussion Starter #3
I did, though not cheaply. Going off memory: the closest dealer changed the #1 fuel injector, SCV, fuel rail pressure sensor (can't remember for sure on this) and the sedimenter/seperator filter. I'm not entirely sure all this was necessary but they certainly fixed the problem. They did say to only use Geniune Isuzu sedimenter filters as they said aftermarket (I put a WIX on previously) "flow too well". I was skeptical of this but out of fear of another problem I've done just that and not had any issues since. I do remember in my research that many people had trouble directly after changing their filter so perhaps there is truth in this. Good luck.
 

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Thanks for the help with this. I ended up changing the SCV (Suction Control Valve) and Pigtail leading up to it. Dead pedal issue / no accelerator / loss of accelerator / no throttle response in my 2006 Isuzu NPR-HD has been resolved. Sorry for all the keywords, but I figured I'd write back this way so that it would help others with the same problem since there is absolutely no info on this on the web.

SOLVED: ISUZU NPR HD - Loss of throttle response / dead accelerator / no throttle / dead pedal
 

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Thanks for the advice, I am having the same problem. I have tried replacing fuel rail pressure sensor, a fuel injector, and I am still trying to diagnose this issue. My mechanic has recommended purchasing a new fuel pump, but I would like to exhaust all other options first. Where did you purchase the SCV & pigtail? Thanks again for the help.


Thanks for the help with this. I ended up changing the SCV (Suction Control Valve) and Pigtail leading up to it. Dead pedal issue / no accelerator / loss of accelerator / no throttle response in my 2006 Isuzu NPR-HD has been resolved. Sorry for all the keywords, but I figured I'd write back this way so that it would help others with the same problem since there is absolutely no info on this on the web.

SOLVED: ISUZU NPR HD - Loss of throttle response / dead accelerator / no throttle / dead pedal
 
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