Cummins Diesel Forum banner

1999 won,t idle unless 1/2throttle

1K views 14 replies 6 participants last post by  atasirudy 
#1 ·
hope someone out there has ideas!? I've got an old fedex truck for a work vehicle that's been treating us real well till about 2 weeks ago. I started noticing a pretty rough idle at all temps and wrote it off to buying cheap injectors bout a year ago . also replaced p-pump last winter but would not expect trouble there yet. found a thread that mentioned the stanodyne product and bought a bottle...wow! 15 minutes and she was running top notch! coming home from work last night she died at a stop light and wouldn't idle unless in neutral but still ran good. This morning,went to start for work and won,t idle at all. tried cranking idle screw a bit but no change. ripped out all throttle linkage and rebuilt lever spring assy. lubed everything and reassembled.Now with my son in cab to keep it running,I see that I'm at 1/2 throttle travel to keep it running and idling at normal rate! I'm kinda lost here and in the middle of a huge job and can't afford to start ripping her apart without any sense of direction.any thoughts would be life saving at this point. some details...
1 year old p7100
2 year old 50+injectors
# 10 fuel plate with a couple turns on the star
2 week old fuel filter
 
#4 ·
1999 won't idle unless 1/2 throttle

Thank you for the replies, I'll check pressure now,forgot to mention the lift pump is less than a year old,and when i was rebuilding the throttle linkage,I noticed the rack doesn't have a smooth travel action, it almost seems like there is some binding going on. Anyone heard of rack springs breaking or binding? I'll also open afc today and have a peek, didn't get a lot of improvement after installing the 10plate on this new pump,when I installed it on the old pump,it made drastic improvements. Looks like I've got a lot of digging to do.
Thanks again
 
#5 ·
Sounds like your governor springs are loose.
 
#8 ·
the thing will still rev, but no fueling untill the pump reaches mid point,not blowing white smoke or anything else...im digging now ,post any finds
thanks again friends!
Once again, check your governor springs, they control the pumps fuel curve.
 
#9 ·
1999 won't idle unless 1/2 throttle

went through all fuel lines and have normal fuel pressure-20 holding at idle and 30ish at high revs. I guess i'll open her up and check the gov.springs...if they are loose, I'm gonna have some nasty phone calls to make! the last IP lasted 320,000 miles and this one has less than 15,000
 
#10 ·
the last IP lasted 320,000 miles and this one has less than 15,000
What are you using for fuel? My injector pump has more than a million miles on it and hasn't skipped a beat. No, I don't use, or believe in, fuel additives of any kind.
 
#11 ·
I've consistently used mobile...we get bad winters so I use an additive only in the bad months, this spring I did buy two tanks of off road "red" diesel due to working way out in the sticks...didn't notice any drivability changes, this truck also has a remote fuel filter/heater,cant remember name..clear dome type. Im wondering if there is something that fedex puts in the relocator,has original paint on it doesn't look like it's ever been opened..the saga continues
 
#12 ·
1999 won't idle unless 1/2 throttle

well i'm still fighting here...up date,one set of gov springs were so loose the adjuster was'nt catching the tabs on retainer..really close to grenading!I matched it to the other side and it idled for 5 minutes and started all this madness again!I removed the afc and the diaphragm was torn to shreds and wastegate actuator was blown out completely.replaced the diaphragm,did afcmod,new actuator and rebuilt turbo while in there. I also removed and cleaned all injectors and fuel system components,set the afc at 22psi to match actuator at 25. once again,started right up but will simply not idle!need this truck,it's my mobile shop and really hurting without my work wheels
thanks again for any thoughts
 
#13 ·
You can start the engine with afc off. From the top you could see if the rack travels with the throttle or not. In your case rack probably not moving till half throttle. That could be brocken gov springs or the governor itself.
I would take gov springs and seats off and inspect them first. Then if they look good and identical to each other, you might want to take that pump off and send ot back

Sent from AutoGuide.com Free App
 
#14 ·
pulled apart one set of springs yesterday and found 5 springs in there,is that normal?never saw that many on cut-aways or images. ran out of time last night so I'll check the other side now...Pensacola Diesel happens to have a lengthy detailed warranty policy which basically says there is no "warranty" if that gov is bad ,I may be parting out a frigging truck.thanks again for reaching out
 
#15 ·
Dude, get a different pump and use that one for a boat anchor or a tire chalk. If you had said you put a pensicola on it in the first post then we could have helped you out a long time ago. There's always genuine Bosch pumps on here for way cheaper than that piece of crap you bought.
 
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Top