Engine dies like key was turned off

[Jeff Erwin]

I need some expert diagnostic help on this one.

71 Charger 440x6. Runs like a top, purrs like a kitten, all that. Completely rewired the car bumper to bumper 18 months ago, everything's been flawless since then, with one exception. Occasionally the car won't turn over with the column shift in P, have to move it to N and the car will start. Doesn't happen every time. I kinda suspect I need to adjust the shift rod down at the transmission. No big.

Then last night I'm driving home and the engine dies. No sputtering, gagging, just like I had turned the key off. Everything electrical is still working, headlights etc. I pull off, put the shifter in P and the car fires right back up again. 10 minutes later the same thing happens again, engine just dies like I turned it off. This time turning the key to restart does nothing, just like it sometimes does (above). I try N, nothing. This goes on for a few minutes as I try moving the steering column, moving the shift lever etc. Eventually, 10 minutes or so, it turns over and the engine fires right up. Runs perfect all the way home, although all my trust is obviously gone.

WTF? I think it must have to do with the key start wiring somehow, then I'm thinking maybe a loose ground from the steering column to chassis.

This one has me baffled. Any thoughts?

 

[Dennis H]

Does a 71 have a Bulkhead connector?

 

[Don67Satellite]

Could be something to do with the Neutral Safety Switch. Mine has exhibited this behaviour on rare occasions. No start in Park, but yes in Neutral. Now that I know what it is, if it happens, I wiggle the floor shifter in Park, and then it normally fires up. If it's not firing in P or N, maybe a intermittent or failing switch?

EDIT: I missed the part that it died randomly while driving. Could be related issue or another gremlin.

 

[Doorkicker]

My initial reaction was a neutral safety switch, but that wouldn't cause the engine to just shut off driving down the road. I think @Dennis H is on to something with the bulkhead connector.

 

[Photon440]

You might also check to see if the power wire to the coil is properly tightened, and not possibly grounding out anywhere to cut the ignition.

 

[Jeff Erwin]

Does a 71 have a Bulkhead connector?

Yes it does, and it was completely replaced when I retired the car 18 months ago. Why would we suspect it? Wire working loose?

 

[HALIFAXHOPS]

So gets hot and dies? Typical condenser shorting when hot if it is a dual point. Cools off and starts again right? Happens alot with the new stuff actually a easy check, use a hairdrier and a ohm meter

 

[R413]

What kind of wiring does it have now? Stock or custom?

what kind of ignition box and coil do you have?

 

[Ron H]

Yep bulkhead? Had a similar, though not the same gremlin having to do with the bulkhead. After installing new engine bay wiring, I didn’t replace the BH – yet. The new wiring harness at the BH connection wasn’t seating properly and wasn’t noticeable until finding the car would start by putting pressure in the harness against the BH. This prodded me to put in a new BH and thought that was the end of it. Not. Closer inspection detected that the poor ignition wire connection had caused over heating loosening the connection inside the new harness. I think driving it with vibration and all caused that wire to disconnect enough to leave me on the side of the road. Plucked that wire/connection out of the harness replacing it and finally all good.

 

[ruffcut]

My money is on bulkhead connector. I had THE SAME THING WITH A pOWER wAGON YEARS AGO AND WHEN IT DIED i WOULD HIT THE KEY TO THE START POSITION AND THINK i HAD TO HOLD IT THERE FOR SOME TIME BUT IT WOULD FIRE UP RIGHT AWAY.
next TIME IT CTS UP GIVE THAT A TRY. ruffcut

 

[Geoff 2]

It is not the N or P switch causing the engine to die once it is running.

The reality is that the problem could be anywhere in the ign cct. There are a lot of failure points/connections that can fail.

But you have to start somewhere, right?

So I would do this simple test. Get a 3w lamp [ or any 12v lamp ]. You want the lamp sitting on the dashboard where you can see it. Ground one side of the lamp; connect the other side to the coil +ve terminal. You can use an alligator clip for this.
Drive the car until it cuts out. If the lamp stayed on, then the problem could be the coil, inside the dist or wiring to the dist. If the lamp went out, then there is a problem in the wiring to the coil. I suggest you try this & report back

 

[Dennis H]

Put a little torque on the connector box while someone else spins the starter. Stand to the side…

 

[Jeff Erwin]

So gets hot and dies? Typical condenser shorting when hot if it is a dual point. Cools off and starts again right? Happens alot with the new stuff actually a easy check, use a hairdrier and a ohm meter

No, engine temp has nothing to do with it. The first time it died the engine had been running about 5 minutes. The second time the engine was at temp. Also no condenser, electronic ignition.

 

[HALIFAXHOPS]

Check the pickup and the ecu also.

 

[Jeff Erwin]

What kind of wiring does it have now? Stock or custom?

what kind of ignition box and coil do you have?

Electronic ignition. MSD coil. A coil failure wouldn't explain the dead key when I tried to restart it.

 

[dadsbee]

Harness plug on the ECU... Female ends get the "throwing the weiner down the hallway" effect and she dies. Had that with my ignition updated 64, squeezed all the terminal ends, put the connector back on and Bob's your uncle.

 

[Jeff Erwin]

What kind of wiring does it have now? Stock or custom?

what kind of ignition box and coil do you have?

American Autowire harness. Wiring was done 18 months ago, no issues until last night.

 

[HALIFAXHOPS]

I have a feeling you have two things going on. Next time it wont crank jump the starter relay and if it cranks definitely something in the crank circuit back from the relay. Dies? Have to troubleshoot it when it happens.

 

[Jeff Erwin]

Yep bulkhead? Had a similar, though not the same gremlin having to do with the bulkhead. After installing new engine bay wiring, I didn’t replace the BH – yet. The new wiring harness at the BH connection wasn’t seating properly and wasn’t noticeable until finding the car would start by putting pressure in the harness against the BH. This prodded me to put in a new BH and thought that was the end of it. Not. Closer inspection detected that the poor ignition wire connection had caused over heating loosening the connection inside the new harness. I think driving it with vibration and all caused that wire to disconnect enough to leave me on the side of the road. Plucked that wire/connection out of the harness replacing it and finally all good.

I will check this.

 

[Dennis H]

Jeff, I chased this for years. Unsettling and dangerous. Been down at a freeway wall in Reno and the top of Carson Pass. Like someone removed keys and threw them out the window. This after 2 years of no symptoms! Be sure to inform us when you get to the other side.