97 Cummins loss of power/fuel pressure

J

JSconi

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Jun 9, 2011
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I have a 97 with a nv4500, 62/71/14 over a s475, fass 220gph, 4k gov springs, laser cut dv's, DDP stg 4s, usually run around 60psi at the pump. When I get to about 2500rpms the fuel pressure drops to 35psi until I snap the throttle and then it goes back up to 60psi. It won't build boost very good either usually I'm around 85pounds of boost at WOT but not seeing over 45pounds now. The truck is also backfiring at times and misfiring it happened after I got fuel; was wondering if I might have gotten bad fuel, gelled up? or if something could have happened with timing or the valves possibly? I'm stumped right now and any help would be appreciated
 
check to make sure there is no water is the fuel filter
check timing
check boost for boost leaks ,
if you don't find anything i would pull the front cover make sure you didn't loose a crank or cam key. That were i would start
 
any white smoke out of the pipe?

backfiring, and that most likely equal slipped timing...
 
I would start with your fuel filter. You should be able to tell a decent amount from that
 
Last edited:
Have u checked the return valve on the pump? I would agree also w slipped timing ...how new are ur componets? Compounds, pump, FASS, etc... whens last time u set ur valves ...also why are you running a 220 FASS
 
Have not checked the overflow valve. Fass is less then 2 weeks old, compounds have been on alittle over a year. Valves were done about 10k ago. And what do you mean why a 220?
 
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