RUNAWAY Diesel - T444E Never thought it was possible
 

Well I'm not quite sure how to explain this as I did not think it was possible for a t444e to "run away" but today I had one do just that. We picked up a couple of chip trucks, 4700s from 02, that have a weak 175 hp rated motor in them. They came from out mid east, and it was -4 when they were picked up. One ignition was left on, the other truck was just as dead. Spent the better part of the day trying to salvage the batteries and they actually recovered well. Took a good charge and then ran errands with each se t in the excursion.

Went out to the first truck and put them in. Right as I hook up the positive lead the starter starts cranking away. Key is off... continued to do this so i said eff it and moved onto the other truck. All I can think of is ignition tumbler needs to be replaced.

2nd truck - batteries are in, thank god this one didn't ghost start on me too, turn key on gauges all look good, go to crank and its kicks right off. Idles for a split second and then goes full throttle, turned key off there is no power to the dash and engine is screaming away. I am just waiting to hear a rod exit the block. She slowly started to rev down until she died. this happened over 5-8 seconds.

Both trucks are bare bones 4700s, 5 spd spicers, both from 02. Tag on the cover say 175 hp - we will change that down the road....

I am in here asking any of you guys, even being a 4700 vs a pickup, how the heck this is possible with a heui motor??? I littlerally almost chit myself, and don't even want to go try again. No starting fluid was used no anything. This has happened to me on a mechanically injected 5.9 befor, in which we were able to shut down quickly. I guess I'll take the airbox off and have a friend standby with a rag, however I am still flummoxed how eff this is possible on a heui motor??? No power, no PW...

So two newer chip trucks, that neither I can start!

What if someone poured gasoline or what ever on the intake before you guys picked them up?

It shouldn't be possible. cut power to the computer, no more injector signal, no ignition.

What about a massive internal oil leak that fueled the engine and since the engine was still turning, the lpop was still pumping, fueling the combustion. I would think that you would have seen evidence of such a leak though. It would have to be before the inlet of the turbo though.... Somewhere to start at least.

On the runaway only way I know that could happen is if some fuel is being sucked into the intake somewhere. Maybe a busted diaphragm vacuum line connected to the fuel regulator system? Don't know that model and fuel system mechanisms to be much help though.

What if there was some kind of short between a power wire and the hot wire to the IPR? I'm just thinking out loud here,I don't know if this would actually cause a runaway engine with a HEUI.

Red

Runaways don't have to use fuel. AFAIK the typical runaway is one that is voraciously drinking oil from the crankcase ventilation system. In this case, the only way to know whether it was something like that, or the PCM somehow still fueling the injectors, would be to have it logging live data right at the moment.

I appreciate all the ideas. Is think after a 1300 mile trip and sitting anything via intake that could have been previously sprayed is gone or evaped. I don't see how much could have been pulled via oil or vapor from the case as it hit maybe a revolution before it kicked over and took off... I'm hoping whatever it was is burnt off now but I'm too chicken to try again till tomorrow.

regarding getting a computer on it... these don't have the standard ob2 ports, they have a weird round one. This is on my list of thing to do as well as get a chip of some sort on the truck to wake it up.

Fuel - if I remember correctly is mechanical like our pre sds on the 4700s...

Turbo oil seal leak. Pull cac tube and check for oil

Will do was going to start with it off.

It is possible for the 7.3, and any diesel today, to runaway. They have extremely high compression and all you need is a source/supply of engine oil and away you go.
Although it's very rare, since once you take away the diesel fuel (shut the key off) there usually isn't enough oil to keep it running.

As for your issues, if the truck wasn't smoking HUGE amounts of gray while it revved up for that 5 to 8 seconds, you have a tuning or wiring glitch somewhere. Give it a try again, with a helper ready to block the intake. See if it's smoking, or what it's doing. Or try plugging it in for a while (if you can) and get the engine warmed up. See if anything changes.

The one that cranked over as soon as you hooked batteries, I'd bet also has an electrical gremlin somewhere. I'd try that one again with a little diagnostics with the start circuit. Or possibly the starter's stuck in the engaged position. We've seen that a handful of times too.

My 6.0 surprised me the other day after work when it was like 5° or something. I fired it up, it chugged, ran with a rough idle, and when I tapped the throttle it went to 3k and sat there for a second or 2, then rpm dropped back to a poor idle. Did that a few times then I put it in gear and held the brake and it idled fine. Sat there for a while till internal temps warmed up (gauge showed oil and trans at 12° when I started.)
It never did that before, must be a tuning glitch with cold fuel maps or something. Could be similar with what you are seeing.

The International Medium duties SUCK trying to diagnose. The computers are pretty much useless.

How hard would it be to convert it to the light duty pcm system?

Any T444E built after 1998 has an International engine control module. While it's possible to use ICP fooling devices on them, there is no way to "chip" one. International dealerships can reflash them if there was a higher-horsepower calibration available but it would require digging on their part to find out.

For what it is worth my 7.3 would not stop cranking last month. Taking advice from a post by DZL JIM I replaced both batteries and have had no problems since. For some reason low voltage seems to have caused the issue with mine.

Yeah, low battery voltage can cause the starter to keep turning. It has the amps but not volts, or something, doesn't make complete sense to me but it can happen.
I didn't bring it up because the OP didn't say it stayed cranking after he started cranking. He said the starter started turning as soon as the batteries were hooked up, so it's a bit different scenario.