Vehicle Starting by itself

dodge
ram3500

#1

I own a 2007 Dodge Ram Pickup (3500). One day it started by itself while parked outside in the driveway. It drove into one of my other pickups and pushed it into my side by side. It finally pushed both aside and was headed toward the house but was stopped by a tree. I heard a loud crashing noise so I looked out the window and saw what was happening. I jumped into the pickup to try and turn it off but the key wasn’t turned on. I put the clutch in and took it out of gear but it just reved up more. The horn was blaring and smoke boiling out. I turned it off by opening up the hood and unhooking the battery cable. Has this happened to anyone else?


#2

Unusual from many respects, I mean first the vehicle probably will not die by disconnecting the battery, second the shift interlock must have failed as it should not start in gear, and 3rd horn and smoke, Poltergeist or bad ignition switch.


#3

Sounds like several coincidental failures all happened at once. What are the chances ? Or one major, underdash short melted some wiring insulation. I like the Poltergeist !


#4

This seems almost impossible, but with many electrical systems being controled by computers, shorts do happen.

Since this is a diesel? Disconnecting the battery may be a fail-safe in case of “runaway”


#5

I’m assuming your parking brake wasn’t on. Although this scenario is certainly unlikely, it points out that it’s always a good idea to set it, which is a topic discussed here from time to time.


#6

Tom and Ray had a caller on the show one time with this problem. Their Porsche started all by itself and drove uphill, backwards, before running into a tree as I recall. Technically it turned out it didn’t start, just that it was in “reverse” and the starter motor engaged, so it was acting like an electric car, being moved by the starter motor, not the engine.

I’ll guess that is what happened to your car. The starter motor engaged all by itself. Possible if you have a manual xmission and you left it in gear.

How could the starter motor engage all by itself? Computer glitch. Ignition switch on the fritz. Most likely I think would be the starter solenoid contacts. Each time you start the car, with 100 Amps, it is sort of like a spot welder, welding on the solenoid contacts. They could get almost welded together from repeat start events, then just some kind of thermal expansion could be enough to make contact, which would power up the starter motor.

If that’s the cause, yes, disconnecting the battery should work. To disconnect the battery in an easier way that removing the cables, there are inexpensive gadgets which can fairly easy switch the battery on and off by turning a knob or something like that.


#7

@GeorgeSanJose…my neighbor’s Ford truck came crashing through his garage door one morning all by itself. He always parked it in first gear. The problem was that the solenoid on the inner fender simply failed internally. When that happened…the starter functioned (engine did not start) and the truck went through the door. A tree in his front yard kept it from ending up in the street.


#8

“The key wasn’t turned on”??? Am I to understand that you left the key in the cylinder? While that should not have caused the vehicle to start, it points to a possible key cylinder malfunction. And your insurance is sure to ask about it…


#9

Can you give any more information? Was the engine actually running? Diesel or gas engine? Where was the smoke coming from? Is the vehicle drivable now? Does it have a remote starter installed?

That sounds like an exciting start to your day to say the least…


#10

Obviously this is a little unbelievable to some of you. Believe it or not this is exactly how it happened. The engine was actually running. The vehicle was shut off and put in 1st gear prior to this happening. The emergency brake was not applied. I really don’t appreciate all the sarcasm but do appreciate those that tried to help. No Poltergeist but I admit very weird.


#11

Poltergeist is out, The common denominator would be a bad ignition switch in my book.


#12

“I really don’t appreciate all the sarcasm…”

All what sarcasm? I’ve seen sarcasm in threads on this board. This thread isn’t one of them.

Has the truck been checked over? Anyone have any idea about what happened?


#13

I drove a 1972 C850 Ford Tractor with a 534 cu in gas engine in the days when tractor-Trailers did not have Maxi-Brakes. I was inside a steel company and got out to ask where the load was.
I had the key in my pocket, and watched helplessly as my truck cranked up and smashed into another truck.
The tractor had a lot of miles in city service and the bearing in the end cap had ground itself to dust and allowed the commutator of the started to move over enough to short against the side of the case. The starter didn’t stop trying to turn until the battery cable burned through.


#14

Running too, not just cranking? You need power to the coil for an engine to actually run … hmmm … Ok, I think on my Ford truck, the way it works is during normal run-mode (key in On) the power to the coil goes through the ignition switch then through a resistor, but during crank-mode (key in Start) this resistor and ignition switch are bypassed via the starter selenoid. To make the engine cold-start better. If that’s what happened in the OP’ers case, when the engine was running the starter motor was also running. Which it normally wouldn’t in run-mode. But that might not be obvious just by listening to the engine. If the OP’ers ignition system is designed in a similar manner, that could offer an explantion only involving the starter solenoid. If not, the it would have to be something involving the ignition switch.

Starting an engine w/out a key used to be very easy, as long as you could open the hood or could get inside the passenger compartment. Do any of you older CarTalk folks like me remember when you could supposedly start a car – if you lost the key say – with just a pack of cigarettes? All you needed was the aluminum foil from the wrapper to bridge the appropriate wires. I don’t recall ever seeing anyone actually do this, maybe it was an urban legend. But with some small jumper wires you could do the same thing and more easily.


#15

But is it a diesel?


#16

2 questions for the OP: Was the key actually in the ignition when it went on it’s joy ride ? Does it have a remote start installed ?


#17

Sounded like it was a diesel so all it needs to run is the fuel solenoid energized and a bump from the starter. Disconnecting the battery would have de-energized the solenoid and shut the fuel off. So either both the starter and the solenoid were activated, or the solenoid and somehow the engine got turned over or had enough heat or compression to fire the diesel. In other words I don’t know but parts to inspect would be the starter relays to the solenoid or glow plugs, ignition switch etc. The fact that it was on high idle though is troubling and suggests maybe further electronic issues.


#18

If it is a diesel, and it likely is, a close look at the schematics for the starter and ignition switch might explain the situation. If self energized the starter solenoid might feed back to the ignition switch where the current could be on a shared path with the fuel cut solenoid.


#19

I should have made it clear that in my post about about the 1972 Ford tractor it was just the starter propelling it but the 534 cu in gas engine had a powerful starter and 2 huge 6 volt batteries.