12 valve p7100 throttle hanging

Jeremy001995

Jeremy001995

diesel mecanic
hi, did sledpull today everything goes good, but, after hard pull full throttle3500-4000rpm, at the end of the track the throttle was hanging at 3000, but can throttle to 4000 rpm, engine return to idle by itself after 5-10 sec the first time, the next pull it took 20-30sec to return to idle by itself, what can cause this? throttle linkage works fine, got no fuel plate and afc live! tanks!
 
Watching this. I'm guessing a hung plunger barrel but I don't have the hands on knowledge to back that up.

Sent from my motorola one 5G using Tapatalk
 
How are you sure the throttle linkage is pulling all the way back to idle? Still stock dodge linkage, depending on the return spring?
 
jasonc said:
How are you sure the throttle linkage is pulling all the way back to idle? Still stock dodge linkage, depending on the return spring?
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throttle works fine on the road, i drive the truck almost every day, all apring are there, throttle hang only after a hard pull in sled pulling
 
You're probably flooring the shit out of it during a sled pull run, compared to the street.

I still say linkage issue.
 
Does the throttle cable have bear wires coming out the end or is the cable enclosed in a plastic cover?

Way back in the day, a group of us on TDR got the NTSB to force a recall due to the throttle sticking on the one with exposed wires.
 
Jff24Gordn said:
Does the throttle cable have bear wires coming out the end or is the cable enclosed in a plastic cover?

Way back in the day, a group of us on TDR got the NTSB to force a recall due to the throttle sticking on the one with exposed wires.
Click to expand...

This or lower the idle like 100rpm and I bet it stops.
 
Jff24Gordn said:
Does the throttle cable have bear wires coming out the end or is the cable enclosed in a plastic cover?

Way back in the day, a group of us on TDR got the NTSB to force a recall due to the throttle sticking on the one with exposed wires.
Click to expand...

enclosed in plastic!
 
It's either loose a 100 rpm on the idle setting or 1 click from each spring in the governor. I'm not certain what the scenario is or what causes it, I just know this has worked in the past for rpm hang in a p pump for me.
 
Just had a thread on this a bit back. Was playing with my gov springs. A bit tight would idle it up. Adjust idle down and it would hang up on a rev. Back out a click or two and see where you are.
 
Vincejax said:
Because governor springs control idle and max rpm. Might want to try a click or few clicks looser on gov springs.
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ya i know gov spring change the idle and max rpm, but just lower the idle with the idle adjust screw will not change anything on the max rpm or hang problem
 
bateman said:
Just had a thread on this a bit back. Was playing with my gov springs. A bit tight would idle it up. Adjust idle down and it would hang up on a rev. Back out a click or two and see where you are.
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will play with gov spring to get de sweet spot, gov spring was on the truck for 6 year, first 2 year no issue, the last 4 year the truck was not running, body job, change engine, nv 5600 to nv4500 swap, change ratio to 4.10 and more. and now the first pull the throttle hang, very strange, it didnt do it on free rev!
 
BigPapa said:
This makes me think linkage, cable, or pedal. You may not realize it, but I imagine you're pushing harder during a pull than normal. Adrenaline does strange things.
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Same thing I'm thinking.

I sold my drag truck awhile back to a guy, he calls me a few weeks later and said on his 1st run the throttle stuck and he had to pull the air kill.

He doesn't know much about ppump motors, so I had him send me picks of the linkage at the pump. He bent the bracket the cable attaches to. He floored the shit out of it.
 
The top of the throttle range doesn't see much action. I'd still take the linkage apart, clean and lube it. May be that simple.

These little plastic guys are a known problem.

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