fuel system problems
#1
Registered User
Thread Starter
fuel system problems
trying to figure out what's wrong with my truck (97 cummins). it seems to run fine at or under about 1/2 throttle, starts fine, idles fine, no smoke. when it needs more than that, ie: in a higher gear going up hill, the rpm's and power just start to drop off until i downshift into a gear low enough that it will go with only 1/2 throttle or less. i have checked the fuel lines, throttle linkage, and intercooler boots and there are no visible problems, but don't have the tools to run a fuel pressure test. from the research i've done, it seems to be one or more of the follwing fuel system components. the commentary is from a mechanic i know.
""Lift pump- can only deliver enough fuel for low
> throttle operation?
Cheap, fairly easy to replace. Most need it by 100k
anyway (especially with running bio)
> Pre-filter/heater - leaking air into fuel and/or
> dirty filter screen?
Pre filter, maybe. Leaks, probably not (would have to
be a BIG leak as it should be pos fuel press and lift
pump would pull enough (~7psi) to see a squirt.
> In-tank intake filter screen -dirty
Probably not. I've pulled the sender units and never
seen enough crap to clog it.
> Fuel shutoff solenoid
Probably not unless the diaphragm came apart inside
the IP. Replacement is about $60 (includes parts/labor
- I get the genuine Bosch SO's cheap)
> Fuel overflow valve
Forget that. That's post flow anyway. Slight chance it
could be bleeding off press pre-IP, but doubtful.""
anyone have any other ideas or know if i can add or eliminate options?
many thanks
""Lift pump- can only deliver enough fuel for low
> throttle operation?
Cheap, fairly easy to replace. Most need it by 100k
anyway (especially with running bio)
> Pre-filter/heater - leaking air into fuel and/or
> dirty filter screen?
Pre filter, maybe. Leaks, probably not (would have to
be a BIG leak as it should be pos fuel press and lift
pump would pull enough (~7psi) to see a squirt.
> In-tank intake filter screen -dirty
Probably not. I've pulled the sender units and never
seen enough crap to clog it.
> Fuel shutoff solenoid
Probably not unless the diaphragm came apart inside
the IP. Replacement is about $60 (includes parts/labor
- I get the genuine Bosch SO's cheap)
> Fuel overflow valve
Forget that. That's post flow anyway. Slight chance it
could be bleeding off press pre-IP, but doubtful.""
anyone have any other ideas or know if i can add or eliminate options?
many thanks
#3
Registered User
The overflow valve is the one part that wears out more than any other on a 12 valve.
Unless you have access to a fuel pressure gauge setup just replace the overflow valve
You won't find a better price than here.
Precision Diesel Injection and Turbo Inc.
Marty Tompkins
888-734-7349
$35 + $7 shipping and handling.
Unless you have access to a fuel pressure gauge setup just replace the overflow valve
You won't find a better price than here.
Precision Diesel Injection and Turbo Inc.
Marty Tompkins
888-734-7349
$35 + $7 shipping and handling.
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