Yesterday as I was gonna back up to a trailer hitch...the truck went to wide open throttle as soon as I switched into reverse. Foot was on the brake already as has to be to switch out of park to do so...
I immediately threw back in park and switched the motor off as the RPM's hit max. Restarted and everything is fine again.
This is the third time this has happened since I've owned this truck for a year now.
All three times this happened just as I went into reverse.
No other problems with this truck ever.
Tuned and Deleated with an H&S tuner.
Anybody got any ideas....No codes either.
Wierd.

 

It almost sounds like a short somewhere, I might take it to a dealer or truck shop and have that checked out, sounds way to dangerous to me.

 

Thing is....What to check for ?
What would cause this.
Hard to figure what to fix if its not doing it when trying to diagnos.
Last time it did this a few months ago I replaced the throttle position sensor.

 

Yea, has to be electrical, I hate diagnosing electrical stuff

 

Ya esp. when you don't know the year truck and all the mods installed.

 

Any codes ever come up.

 

Oh.... Sorry about that 69cj... I forgot that my profile doesn't show up when posting from a mobile device.
It's a 2008 Fx4 crew cab 6.4 powerstroke.
Mods are listed in the original post.
Tuned and Deleated with an H&S Tuner .
I keep it on HD300 all the time.
No Codes either as stated in the original post.

Wanting to know if this has ever happened to anybody.
And if it did ....did you find out what caused it or not .

 

This may be a long shot here, but has happened in our department twice. Once with a 6.0L and once with my '08 6.4L. I had never heard of a 'runaway diesel' before this occurred. On both occasions, the prisoners that work on our ambulances at the county shop, over filled the engine with oil. When the units were fired up, they went full throttle! The 6.4L was able to be shut down by just turning the key, however it did not work so well for the 6.0L. It stayed full throttle for several minutes, when it was fired up to check oil pressure, as they were trying to figure out how to kill it. Finally it quit on its own. On both occasions, the crankcase was filled with an automatic oil delivery system that was set incorrectly and WAY TOO MUCH oil was put in. In the 6.0L there was over 15 GALLONS of oil put in instead of 15 quarts! The entire turbo system had to be disassembled to get all of the oil out. The air filter even had oil in it!!!! On the 6.4L there was almost 6 gallons of oil put in which resulted in the same thing, only it shut down by turning the key. I never expected a common rail truck to do this, as the 6.0L did. But I never expected them to do that twice either!!!!! Got to love inmate labor on emergency vehicles! With the 6L's injectors firing off of oil pressure, I can see it. But I don't understand why the 6.4 did it too. Your problem does sound electrical to me, seeing as how you were able to shut it down and restart with no problem, however just throwing out there that there is something else that will cause one to go full throttle. Have you checked the wires going to the throttle position sensor? Wonder if one of them has got a chaffed spot on it somewhere?

 

Might be something in the tuner. Did one of the previous times occur before the tuner, or on a different tune level. You might want to try the H&S web site forums. There is a lot of stuff oin there. Also, have you tried reloading the tune. just a thought.

 

I think either a tuning issue, or oil entering the intake somehow.

I doubt it could be electrical, as the throttle has 3 potentiometers in it, so you'd need all 3 to fail, and they'd have to fail in a way thats almost impossible. I believe 1 failed also sets a engine light.

I can't imagine any other electrical could cause such an issue either.

 

ya know had something like this today, was backing up and right before i threw it back into drive it surged HARD but stopped when it was in drive. didnt know if it was my new boots or same as you had? also running HD.300