700r4 TV cable cause acceleration/run away with 6.2?

plugugly · Thursday at 12:38 PM

My son just told me that after driving on the freeway for a while, he will have this intermittent problem:

When he lets off the throttle, he feels like the pedal will "suck down" and the truck will accelerate. When he steps on the brake, it will stop. I have not witnessed this problem myself, so Im using teenager explanation. Is this possibly something related to the TV cable, as I am not too familiar with them. OR, is this more likely a 6.2 diesel issue?

Vbb199 · Thursday at 1:30 PM

Following... im interested

gmbellew · Thursday at 1:51 PM

Is the cruise control somehow sticking on or somehow being engaged? Cruise control is the only thing i can think of that will suck the accerator pedal down. And the brake pedal switch will turn off the cruise and stop the issue. Is he accidentally "setting" the cruise when he uses the turn signal to exit the highway?

Ricko1966 · Thursday at 2:01 PM

Not possible for the TV cable to open the throttle. Even if you took the pan off,grabbed the TV cable with vice grips and pulled on it. It would be pulling the throttle closed,not open.

Blue Ox · Thursday at 2:06 PM

Ours would stick sometimes after it was a few years old. However, it would just stick, not accelerate. You could get it back by smacking the pedal with your foot.

It all went away when we replaced the throttle cable.

plugugly · Thursday at 3:58 PM

gmbellew said:
Is the cruise control somehow sticking on or somehow being engaged? Cruise control is the only thing i can think of that will suck the accerator pedal down. And the brake pedal switch will turn off the cruise and stop the issue. Is he accidentally "setting" the cruise when he uses the turn signal to exit the highway?

good point. Cruise, to my knowledge, is not hooked up, but I will need to double check.

thanks for info on TV cable. Sounds like it may be a bad accelerator pedal. Ill have to look into lubricating and/or replacement

Vbb199 · Thursday at 7:45 PM

I was theorizing something crazy like when letting off the throttle , manifold pressure increases, and its consuming oil thru a leak or something but i didnt think diesels had "manifold pressure" per say... that gasser boyz territory

I supposed cylinder pressure could increase during deceleration events or something, but that sounds dumb too.
Which is why i originally just said im interested and following lol , im so lost with diesels

Ricko1966 · Thursday at 7:47 PM

Vbb199 said:
I was theorizing something crazy like when letting off the throttle , manifold pressure increases, and its consuming oil thru a leak or something but i didnt think diesels had "manifold pressure" per say... that gasser boyz territory

I supposed cylinder pressure could increase during deceleration events or something, but that sounds dumb too.
Which is why i originally just said im interested and following lol , im so lost with diesels

I've had a diesel run away by sucking crankcase oil. It's not likely,but you should read up on it,and check your intake for engine oil. I got lucky the brakes were able to overpower the engine and it was a manual transmission so I was able to kill the engine.

1STLS1 · Thursday at 8:51 PM

Ricko1966 said:
I've had a diesel run away by sucking crankcase oil. It's not likely,but you should read up on it,and check your intake for engine oil. I got lucky the brakes were able to overpower the engine and it was a manual transmission so I was able to kill the engine.

I came here to post this. If its ending up with blow by pooling in the intake from a long highway cruise, that turns into fuel and the motor will start to run away until it's out of the extra fuel.

I haed a VW Rabbit Diesel I bought off Ebay for $95.95, that needed a cylinder head, got the motor back together and found the rings were out of it too. Running down the highway, every 5 miles or so she would start running faster and faster then slow down for a couple miles then do it again. At first it was scary but drove it like that for another year before giving it to my buddies brother, he drove it locally for another year or so.

Vbb199 · Thursday at 10:30 PM

Ricko1966 said:
I've had a diesel run away by sucking crankcase oil. It's not likely,but you should read up on it,and check your intake for engine oil. I got lucky the brakes were able to overpower the engine and it was a manual transmission so I was able to kill the engine.

I was pondering that too, like blowby causing it to take off or something

Grit dog · Thursday at 11:07 PM

Good news is not a runaway. They don’t just “stop”. Just like death wobble. If you only “think” it happened, it didn’t.
Probably sticky throttle cable or weak spring or both?
It’s an old truck. Both my squares are original and they both stick a bit once in a while. Or not at all for a long time.
Next time it happens tell him stab the throttle hard momentarily and see if it returns to normal as well. If so I’d say cable.
Unless there’s something that opens the pump up further by itself. But I’m not familiar with 6.2s.

Craig Nedrow · 2024-11-25T16:20:19-0500

On my 6.2, when it is cold, and is have steady peddle pressure, the engine does rev up some, then shifts and etc. It is not a big problem in my case, and I think it is a governor adjustment...or not. Never ran away.

peats · 2024-11-25T16:34:37-0500

I recently had to replace the throttle cable on my 6.2. It was sticking, not accelerating. Was able to get a GM part.

Nardulli · 2024-11-26T15:18:17-0500

As someone else said, the TV cable cannot cause the throttle to open. It would be impossible. It seems odd that the gas pedal would 'suck down'. Is he certain about that? This is a 6.2 diesel?
I'm not familiar with the fuel injection setup on those old engines, but that's where I would start. stepping on the to stop it sounds like a cruise control related issue - you may not have it fully hooked up, but there still may be a vacuum circuit in play.

700r4 TV cable cause acceleration/run away with 6.2?

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