So I have this 1990 L9000 with an L10 PT pump with a Model 404 Jake, and it starts and runs great. The problem comes when you ever so slightly blip the throttle it will ramp up to 1550-1700rpm, and will increase from there until high idle limit. ~2200rpm. To bring it down from this high speed the throttle must be hit full sharply and let off. There are no linkages that are seized, and customer claims that pump was rebuilt sometime ago. The return does not seem to be plugged and there are no electronics on this unit. I am at a loss. I will upload a YouTube video soon and post the link here. Thank you in advance, Dion
Sounds like classic air in the fuel to me, but I will talk to my Cummins expert and get back to you. Or, another thing to check is remove the pin from the throttle linkage right at the arm on the fuel pump. There is a cushion spring built into the arm, they are known for crapping out.
http://youtu.be/PFcDUyUAKto
I would say the pump needs to come off. Good thing is they are not hard to take off. Just a spined shaft.
When you shut the switch off, does the engine shut right off or does it stumble awhile before it shuts off?
I didn't pay attention. Stubble would make more sense.
Wow this is old. Figure I'd update whoever cares though. I found the issue to be caused by a combination use of biodiesel and sitting. Bacterial growth was found on the governor shaft causing the weights to stick closed. Pump was rebuild, installed, customer still uses biofuel, still lets it sit. See you in a few months again!
Old? If you look, you can find threads from 2007, maybe earlier. Lol. Thanks for the update though.
Thanks for the update,,, that's how we learn.