Engine stopped while driving, and then................

[nomadci]

So driving along enjoying the sound of the 426 purring in the breeze and then hesitation....and cut off! Swing car into left turn lane and coast to a stop on a neighborhood street all the while fighting the power steering which now has no power. Turn the key and the engine starts back up, pump the pedal and she sounds fine. I had just left a gas station having filled up from 1/4 tank so I'm thinking either bad gas, trash in the fuel filter? I need to get home, only a half mile away, turn back onto the highway, get about a hundred feet and she stalls again, this time only a church parking lot available to get her off the street. I turn the key and she wants to fire up but as soon as I release the key she dies. Tried this several times before realizing I'm not driving home from this one. I take off the air cleaner, gas squirting in carbs, no obvious reasons she won't start. Call a tow truck. An hour later and $150 lighter (only .5 mile from home) I get her in the driveway. Can't get her in the garage, uphill and the tow truck only got me in the driveway. Check the fuel pump, fine. Fuel filter, fine. Will check again tomorrow (92 degrees and frustrated). Today, start checking the engine wiring harness and notice a burnt connection at the 4 prong plug on the passenger side valve cover where the alternator/coil connect to the engine harness. The black wire and housing around it are burnt, plastic melted. Checked the fire wall connections no signs of damage. Of the four wires in the plug, only the 12BK is damaged. I cut the wire from the harness and splice it together and still the engine will not remain running. Only runs with key in the crank position! Release key, engine dies. No current at the ballast with the key in the on position. Ignition? Harness? Ammeter? No blown fuses. Original ignition system, harness and dash components.

 

[Michael_]

Only runs with key in the crank position! Release key, engine dies.

But as long as the key is in crank position the starter constantly runs, right?

I cannot really help but if i was in your situation i might try to connect the positive term of the coil with the positive battery post using a jumper wire and then jump the starter relais on the firewall using a screwdriver and see what happens / if it stays running this way.
If so this might help narrow it down. If you are gonna try this: Make sure the transmission is in park.

 

[Dennis H]

Bulkhead. No cost to try. Gentle move, then spray with electronic cleaner. Profusely.

 

[The Rebel]

I'm no electrical wizard but perhaps the fuseable link burned out or starter relay is bad.

The short went to the weakest link in my opinion so that caused the burnt wire.

 

[hunt2elk]

Ballast resistor?

 

[dadsbee]

Jump the ballast resistor... see if it runs.

 

[Dave6T4]

Although your harness is different than my '67, that black wire is the power wire from the alternator. Mine shorted out near the alternator, recently, and burned the fusible link off at the bulkhead connector. This saved my wire harness under the dash from burning up, although the red and black ammeter wires were crispy at the inside of the bulkhead connector. Trace your wire back, and see what happened there. That melted connector shows that there was a lot of heat there. I also eliminated the ammeter gauge connectors in the firewall terminal block by drilling them out of the block. I then spliced new red and black ammeter wires into my dash harness and ran them straight through the holes in the terminal block. I added a new fusible link wire to the red wire and terminated it at the starter relay on the firewall. The end of the new black wire was spliced to the alternator power wire at the firewall. Cars are like computers; once you let the smoke out of them, they don't work any more.

 

[Kern Dog]

Either things changed a LOT for 1970 or that 4 wire plug is not stock.
The situations where an engine wants to run ONLY with the key in the start position is often related to the porcelain looking ballast resistor. Yours should look sort of like this:

When they go bad, one of the things that can happen is the engine will run with the key in the START position but then shut off once you release the key to the RUN position. The back side of them may have evidence of burning, blackening or a break in the winding.
Yours may have been failing but still sort of working…. Until it didn’t work at all.
One time I had the car idling in the shop. I closed the hood and the car stalled. After looking at several things, I removed the resistor and found that the winding in the back had actually split!

 

[Rocky05]

Either things changed a LOT for 1970 or that 4 wire plug is not stock.
The situations where an engine wants to run ONLY with the key in the start position is often related to the porcelain looking ballast resistor. Yours should look sort of like this:

View attachment 2063193

When they go bad, one of the things that can happen is the engine will run with the key in the START position but then shut off once you release the key to the RUN position. The back side of them may have evidence of burning, blackening or a break in the winding.
Yours may have been failing but still sort of working…. Until it didn’t work at all.
One time I had the car idling in the shop. I closed the hood and the car stalled. After looking at several things, I removed the resistor and found that the winding in the back had actually split!

HEMI only

 

[PurpleBeeper]

You have lost power at the blue wire going to the ballast resistor. The brown wire provides 12V to the ignition while cranking but the blue wire provides 12V while running. If you “had” to, you could make a “jumper wire” from the battery + to the blue wire connection on the “in” side of the ballast resistor, turn the key & it would run (basically hot wire your own car). Un-hook the jumper wire and the engine shuts off.

Try the bulkhead connection. It’s on the same circuit plug as the brown wire. Clean it & also push the engine side of the connection with a teeny tiny screwdriver (to push it forward a little bit extra)

 

[1 Wild R/T]

Either things changed a LOT for 1970 or that 4 wire plug is not stock.
The situations where an engine wants to run ONLY with the key in the start position is often related to the porcelain looking ballast resistor. Yours should look sort of like this:

View attachment 2063193

When they go bad, one of the things that can happen is the engine will run with the key in the START position but then shut off once you release the key to the RUN position. The back side of them may have evidence of burning, blackening or a break in the winding.
Yours may have been failing but still sort of working…. Until it didn’t work at all.
One time I had the car idling in the shop. I closed the hood and the car stalled. After looking at several things, I removed the resistor and found that the winding in the back had actually split!

Like Rocky mentioned, Hemi Only.... You need to step up your game to get the engine removal plug....

 

[Kern Dog]

There isn’t much that I know about Hemi cars.

 

[Rocky05]

There isn’t much that I know about Hemi cars.

I have been staring at that wiring diagram for my 68’ for years! I couldn’t help but respond.

 

[not so famous bob]

So driving along enjoying the sound of the 426 purring in the breeze and then hesitation....and cut off! Swing car into left turn lane and coast to a stop on a neighborhood street all the while fighting the power steering which now has no power. Turn the key and the engine starts back up, pump the pedal and she sounds fine. I had just left a gas station having filled up from 1/4 tank so I'm thinking either bad gas, trash in the fuel filter? I need to get home, only a half mile away, turn back onto the highway, get about a hundred feet and she stalls again, this time only a church parking lot available to get her off the street. I turn the key and she wants to fire up but as soon as I release the key she dies. Tried this several times before realizing I'm not driving home from this one. I take off the air cleaner, gas squirting in carbs, no obvious reasons she won't start. Call a tow truck. An hour later and $150 lighter (only .5 mile from home) I get her in the driveway. Can't get her in the garage, uphill and the tow truck only got me in the driveway. Check the fuel pump, fine. Fuel filter, fine. Will check again tomorrow (92 degrees and frustrated). Today, start checking the engine wiring harness and notice a burnt connection at the 4 prong plug on the passenger side valve cover where the alternator/coil connect to the engine harness. The black wire and housing around it are burnt, plastic melted. Checked the fire wall connections no signs of damage. Of the four wires in the plug, only the 12BK is damaged. I cut the wire from the harness and splice it together and still the engine will not remain running. Only runs with key in the crank position! Release key, engine dies. No current at the ballast with the key in the on position. Ignition? Harness? Ammeter? No blown fuses. Original ignition system, harness and dash components.

View attachment 2063157

View attachment 2063158

Like the car !
Had a similar problem on my form S fastback , I accidently grounded the POS. battery post , and shorted something, it would stall when I hit a bump and restart if I was going fast enough.
I was having major health problems due to my heart doctor(quack) putting me on statin drugs , still recovering 3 yrs later , anyway I had it completely rewired by alocl hot rod shop , fixed !!

 

[nomadci]

But as long as the key is in crank position the starter constantly runs, right?

I cannot really help but if i was in your situation i might try to connect the positive term of the coil with the positive battery post using a jumper wire and then jump the starter relais on the firewall using a screwdriver and see what happens / if it stays running this way.
If so this might help narrow it down. If you are gonna try this: Make sure the transmission is in park.

 

[eldubb440]

awesome car , good luck with the fix

 

[nomadci]

You are correct, starter constantly running. Will try and jumper it rom the battery this evening to at least get it in the garage.
Thanks for the tip!

 

[nomadci]

Okay, So I ran a jumper from the POS+ of the battery to the + of the coil and she started....and kept running when the key was released! So I pulled her in the garage (thank you) and turned the key off, fully expecting the engine to keep running. It didn't. It turned off when the key turned off? So I started again (jumper still in place), turned it off and it turned off. So, I then removed the jumper, turned the ignition and SURPRISE it started normally. Repeated this three or four times with the same result. So I had not removed the harness from the bulkhead, reset the wires, checked the fused wire link, nothing! Other than jumper the car to get it started. Now I'm back to square one because I don't know what caused the engine failure to begin with. I then checked and cleaned the bulkhead wire connection, pressed the black and blue heavy gauge wires in firmly with a small screwdriver, removed the ballast and checked it (it is completely enclosed) with no visible damage. I did however notice that the ballast was very hot to the touch after the engine ran for a short time. Is this the culprit? Now I have trepidation's about driving anywhere for fear of another engine stoppage.

 

[Daves69]

Not saying this is your issue but something to check.
This happened to me on my '69 Barracuda just last year a few blocks from home.
I had intermittent contact in my fusible link and the car would run, die, run, die, run, die. I did that all the way home and it killed my alternator.
Anyway, the culprit...............

Testing circuits

Hi following on from my questions about the wiring on my ballast resistor, I realise that I’m going to get nowhere until: A. I teach myself the basic layout of the circuits that start, run and charge. B. Get a multimeter and test the various parts of those circuits. So starting with the basics...

www.forabodiesonly.com

 

[joseph p.]

Check the pick up coil, in the distributer my satty would get hot then cut off,waited 20 minutes it would start ,the black heat shrink was nearly gone,just saying.