Archived Wide open throttle after lift pump change

[VHazelbaker]

Please help i need information!



I just changed my lift pump out. When I start the truck it immediately goes to wide open throttle. I did the starter bump procedure several times to bleed the system first. Every time I start my truck I have to immediately shut it back down do to the high rpms. The truck is a 1999 2500 24 valve. Any suggestions or ideas as to what I should do next would be greatly appreciated.



Vince H

 

[Shooter]

did you check your throttle cable to see if it is stuck, check the tps.

 

[VHazelbaker]

High rpm problem solved

Thanks for the reply. I disconnected the batteries then reconnected them and went through the bump the starter routine again and it fired up at the correct engine speed. I don't know if unhooking the batteries was the true fix or not. I know that I am very relieved that it is running correctly now. I went fom idle fuel pressure of about 8-9psi to 15 psi at idle.

 

[tropical trim]

Hazelbaker,

Why did you change your lift pump? I'm asking because I'm having low power on my truck . What symptoms did you have before e the change? Thanks Kyle

 

[VHazelbaker]

Reason fo lift pump change.

Hi Troical trim! I have a small liquid filled mechanical guage that I installed on top of my fuel filter housing. haven't had the money to do the fancy electronic guage inside of the cab like most use. Any how I have listened to fellow members talk about VP44 injection problems that were created by low fuel pressure problems. My best pressure befoe the lift pump change at idle was 8-9 psi. I was unable to tell what the psi fell to at WOT. It also seemed that after a long trip on interstate I didn't seem to have the power or seat of the pants feel. I purchased my truck last year with 100,000 miles on it and suspect that it has never been replace until now. I hope this has answered your question Tropical Trim.

 

[RATTLINRAM]

Resetting the apps

One of the things that seems to help on these 24 valve trucks when there is a throttle problem, is resetting the apps - (Accelerator Pedal Position Switch).

Disconnect both batteries, turn on the ignition, let it set for at least 30 minutes.

Turn off the ignition, hook up the batteries, turn on the ignition without starting, slowly push the accelerator to the floor and let up slowly.

Turn off the key and then start the truck.

It seems to have cured problems concerning the throttle for quite a few people.