gozapper

I was driving 70 mph on the freeway a while ago and when I let off the foot pedal, it kept going 70 MPH!

Od was not on. Got off the freeway, opened the hood and checked the linkage. All seemed ok.
sitting in park, the engine was running high rpms. Moving the linkage did not make any difference.
Got back on the freeway heading home, running in od 70 mph until I had to stop for stop sign. Shifted into lower gears for the stop. got home and can not find anything missing.

Is this something happening inside the pump?
This always started right up on the first turn of the starter.

Any suggestions appreiciated,

Tom

92smokin blacky

does it hang at the same high idle the whole time? could you get the truck to turn off fine with the key?

Rick 12v CTD

if the truck would turn off with the key I doubt it's the typical runaway. If you've turned the fuel screw in real far it could be "floating" because it's just that close to runaway but I doubt that.
Maybe the fulcrum lever broke? I don't know. I don't even know the true symptoms of that though. I've heard it just revs at WOT when it does break.

gozapper

It does turn off with the key.

When it starts back up, it goes to the same high idle.

It is not a wide open throttle because, running 70 MPH, I can push the peddle to the floor and it will go to 80MPH.

I checked the dealer records and the recall was done in 94.

I just got the truck recently and do not know the history of what might have been done to the IP.
thanks for the response,

Tom

wannadiesel

Is it turned up or still stock?

gozapper

I have had this for 2 years. It had some title problems, so I just used it around close by the neighborhood.
On the black top roads 50 or 60 mph. It drove normal no problems.
Drove to town today for inspection and got tags. Went on the freeway and the problem started.

I don't know any history of it. It had a 5th wheel hitch and 273 K miles. Could have been used to deliver rvs. don't know for sure.

I will read the sticky and check the fuel screw.

Strange that it started doing this all of a sudden. I had floored it before with no problems. I have a 300sd and I always drive my diesels hard from a stand still up to the speed limit.

I towed a 18000 lb load of hay with it for 10 miles. It did good.

RollinCoalSmoke

Back the fuel screw out 1 turn and see if that helps.

93 12v

Does the throttle plate contact the idle screw on the engine side of the pump? Try pushing the linkage towards the front of the engine. Also, look at the idle screw itself to see if the jam nut worked loose and the screw vibrated towards the throttle plate, holding it at a high idle setting. May be as simple as backing the idle screw out. Easy stuff first. When I changed my governor spring, my throttle shaft would hang up a bit after putting it back together. It ran at about 1200 or so rpm and wasn't even touching the screw. Just had to work it a bit until it came back down. Well any way, hope it's nothing serious!

Rick 12v CTD

I wonder if the throttle spring broke or slipped off or something... In the winter when it's really cold my throttle shaft has problems returning to idle just from the cold and it's totally fine.

Is your truck an auto or a manual?

gozapper

It is an automatic.

I thank you all for the response.

I will check it out in the morning. How do I get to anything that is between the pump and engine? Do I need to remove what ever that is on top of the pump?

It's going to to 31 tonite. I got one tractor I need to drain. Gotta get antifreeze into it tomorrow for sure.

Thanks again,

Tom

93 12v

It's pretty tough to get to back there. Some have enough patience to fool with it like me, some have fabricated tools to take the frustration out of it. The jam nut is usually at the rear of the pump. THe screw has a flat head slot at that end. A long, thin screwdriver worked best for me. Disconnecting the fuel return line might make a little more room for you. The idle screw is at the top engine side of the pump, the fuel screw is almost halfway down the rear of the pump, same side as the idle screw. It might have a sort of cone shaped cap on it. If it does, then it probably hasn't been adjusted. I think the sticky has more info on all the adjustments. It may give you some insight into how it all works. But the fuel screw, Idle screw, throttle plate are likely culprits. If thats not it, my next guess would be governor spring, o-rings, something internal causing it to fuel up. Keep us updated!

JQmile

That only happens to my truck when the pump is turned way, way up....it hangs at about 70-75 mph. It's weird that it would have happened all of a sudden. Let us know what you find.

gozapper

YEA!!!!!

It's fixed !! I am almost ashamed to reveal the problem, but here goes:

The truck sat unused all summer and the pack rats made a home under the hood. They were storing their food and a walnut had fallen in between the throttle stop and screw. This happened after I went down the free way 20 miles!
I removed the walnut and all is back to normal.

I apoligize for the mis labeled subject line. It was not a run a way. I knew better than that. Was just brain dead trying to figure it out.

You guys that answered, thank you very much. Your answers led me to the problem. Again thanks!
Next project is to do the KDP. I have already done one on my 98 holy grail
4wd, quad. That one is leaving as soon as I get the new transmission in.
I hate working on the 2nd gens.

This 92 1st gen D350 is going to be my keeper. I need to smooth the ride a little tho.

Again, this site is the best one on the internet for being so complete.

Thanks,

Tom

The_Head

**** pack rats. They filled the aircleaner to my moms minivan up with dog food when we used to live out in BFE many years ago.

Riflemanusmc

With you on that one John...