Touchy throttle

[1996c2500]

Hello. I need help diagnosing a problem I'm having with my 6.5 td. It starts a idles fine but when driving it'll not want to lockup the torque converter. I don't believe it's a transmission problem though. The throttle is really touchy and I can't hold a constant rpm without the throttle wanting to redline. It does this in neutral also.

I don't want to start throwing parts at it.

[Robyn]

Welcome to TDP :):)


This symptom can be an indication of a failing injection pump,

If you can't gradually raise and lower the RPM without the engine getting real whizzy, then the IP is likely going south.

[scottm]

Throw a new PMD at it first.

[Dvldog8793]

Howdy
Try to bring up 1000rpm and hold it for few seconds then go to 1200 for few seconds then back to about 1500 for few and then try to drop back down to 1000 and hold. If it wants to wonder or jump around then the IP is probably on its way out.
Good luck!

[arveetek]

I've had the same symptoms with a failing PMD / FSD (fuel solenoid driver). Very common failure point on the 6.5L.

Replace the FSD first before condemning the injection pump.

Casey

[1996c2500]

Howdy
Try to bring up 1000rpm and hold it for few seconds then go to 1200 for few seconds then back to about 1500 for few and then try to drop back down to 1000 and hold. If it wants to wonder or jump around then the IP is probably on its way out.
Good luck!

I can hold 1000 rpm but as soon as I try to go any higher it'll take off. I'll start with a new pmd. Thank you guys.

[Kennedy]

Touchy throttle most commonly comes back to the injection pump. Something in the metering gets sticky and it has trouble adjusting smoothly.

Fuel quality is common culprit. A good additive like FPPF Total Power is mandatory in my experience. Ordinarily the DS4 pump lives a long happy life with the exception of the electronics that are prone to fail.