Car just quits, please help

[Tusc]

Battery sounds good.

What your dealer said about the cam position sensor makes a lot of sense and could fit the scenario - but the lack of any engine codes being thrown negated that possibility before the dealer replaced it. Other sensors like IAT are probably ok as well or they would throw a code.

I'm going to say that there must be a loose ground somewhere. That's my best guess without being able to pour over the car. I've done more than my share of wiring with late-model cars and faulty grounds will ruin your day. I know the Viper has 5 coil packs that each fire for two cylinders as well as providing spark twice to those cylinders. It would seem that the most logical place to look would be between the coil pack and the ignition/computer (since there is no distributor).

From personal experience, if you have any loose connections, corroded connections, bad grounds, partially frayed wires, or electrical components that are on their way out... these could all duplicate what you are seeing.

A dying starter solenoid on my Camaro would allow me to crank and fire the engine, but it would flip over and kill the ground if I went over 1100 rpm. But my car is "special" - a wiring nightmare due to the conversion.

We know you have fuel and the power to run the fuel pump, but the problem is that spark disappears... when? As soon as you start to move the car or put it in gear? Once its moving and the car gets jostled? After a specific period of time?

It sounds like a royal pain. The hunt may take some time, but I'm guessing it will be something small when you find it. Good luck, and keep us updated as you go.

 

[HP]

I don't have my manual with me, but if it were me, I would
check the bundle of wires that come off the + jumper post.
You will have to unwrap the bundle of wires that are powered off
the jumper post and travel just under the fascia below the
windshield wipers. I'm thinking there is a pair of gray wires
that feed power to the coils. Anyway, it won't take long to
do, and it will eliminate 1 variable. To pin-point the
area look right below the driver side wiper - that's where
the main + cable branches off to feed 5 or more fusible links.
These links can short and still have intermittent connection
with surrounding hot wires.

 

[Tusc]

That sounds like it has merit.

I wish I could give more direct advice like that. I guess I'll have to buy a Viper this year so I can tool on it myself!

 

[Ulysses]

I don't know if the early model Vipers have this, but there is a second wire on the positive battery post. If that corrodes at the connector, it can give you all kinds of problems.

 

[HP]

Looking at your post again, I'm puzzled that
you state that the fuel pump is uneffected through all this.
If the cam or crank sensors signals or the power for the coils
or injectors is cut - the auto shutdown relay - will power
off the fuel pump. - ????

 

[Chuck Greggs S Arizona ACR]

Good advice from everyone above.

My own experience: In 1994, my one day old Viper(with about 100 miles) would not start in a Burger King parking lot. Just kept cranking over, but not firing. It was running fine up until then. Finally had to call the dealer. They sent a truck to pick it up. It took them a week to figure out what the problem was. They finally found the cam sensor wiring was shorting out on the exaust manifold heat shield. After the repair, started fine. Then.............a few days later, it started dying while driving. But after a few minutes, it would start up again. It may be okay for a while, or may die a few minutes later. So, I started looking for the problem by jiggling wires around while the engine was running. BINGO! When I moved the large wiring harness connector located at the front passenger side of engine, it would die. I pulled the connector apart, and found that some of the pins were pushed back(female side), not allowing a good connection. Repositioned the pins and carefully reconnected. The mechanic must have caused this problem while troubleshooting the first problem. Hasn't happened since.

Good luck,
Chuck G

 

[joe117]

Start the engine set the brake take it out of gear. Get a wooden stick and start tapping on anything that looks electrical under the hood. Not hard enough to break anything but give everything a little whack or a push. Wire bundle plugs, relays, wiggle the fuse for the ignition, ground wires where they connect under some screw or bolt, You get the idea. If hitting a bump with the car makes it stop, you should be able to tap on some part and get it to repeat. Can you make it do this by bouncing the car while it's sitting, or does it have to be driven over a bump?

 

[Tiepilot]

You beat me to it joe117. That's the best way (or one of the best ways) to ferret out a bad electrical connection. Gotta hate those gremlins!