Engine: Unexpected shut-off.

[showbizkid]

I experienced something totally unexpected today. While sitting in traffic, Barney simply... shut off. He started right back up again, but I'd like to figure out what caused this.

Here's the configuration: 259 4bbl with FOM, less than 3000 mi. on the rebuild.

• Rebuilt Delco distributor with new Uniset points/condenser.
• Freshly rebuilt WCFB installed at rebuild.
• New OEM-spec coil.
• New ignition switch.
• Complete re-wire.
• External ignition ballast resistor - no resistance wire in the harness.
• New mechanical fuel pump with the rebuild.
• Freshly rebuilt Prestolite alternator, fully charged battery.
• Solid-state voltage regulator, Chrysler-style.
• Only electrical ignition parts NOT replaced are solenoid and voltage regulator.

When this happened, the car was fully warmed up after about 1/2 hour on the road. I had just stopped to fill the gas tank and had idled for about 5 minutes waiting to get back into traffic. Warm day, about 76 degrees, temp gauge showing just a touch warmer than the middle of the scale due to the shutoff / restart / extended idle cycle. I had just pulled into traffic and immediately got stopped by a red light, and was idling with the nose of the car pointed slightly downward when, all of a sudden, the engine just shut off, like I'd turned off the key.

I shoved him into Park and he immediately fired back up and ran flawlessly, so it's not vapor lock.

With all that information... any clues? I'm leaning toward the voltage regulator, but I'd love your opinions.

Thanks!

[james.seagle]

Possibly a loose battery cable or connection on the alternator? Other than that, I'm stumped...

[Skip Lackie]

"the engine just shut off, like I'd turned off the key."

Did it act like the ignition was off? In other words, did you notice whether the gauges were still functional? Radio still on?
If not, could be a bad ignition switch.

[christophe]

If the gas tank has just been filled before, I would suspect filth or water in the gas. It happend to me with a full tank. I had to drain the bowl carb and clean the jets every 40 km of a 400 km journey. Of course, it was during the night and it was raining.

[Bud]

I don't believe your voltage regulator is at fault as the engine restarted indicating the battery is charged. I've had that happen to me a couple of times after extended idling. I believe it's gas boiling in the carburetor causing a flooding condition. We have to use the E10 gas in California which has a different Reid vapor pressure from the gas that we originally used in the older engines. The newer fuel injected engines are designed to run on this stuff where carbureted engines don't like it. Bud

[showbizkid]

Bud, that tracks with what I perceived. I was discussing it with my son and we thought "that sure sounds like vapor lock... but it restarted immediately." Your explanation fits.

So would the preventative cure be to put in an auxiliary electric fuel pump, or would that matter? If the fuel in the bowl is boiling, fuel delivery won't matter so much. Maybe I need to put some carb insulators in?

[doug]

I'm with Skip on the ignition switch. My Lark did this a couple of times while driving. R & R ignition switch 14 years ago and no repeats.

[Dick Steinkamp]

Bud, that tracks with what I perceived. I was discussing it with my son and we thought "that sure sounds like vapor lock... but it restarted immediately." Your explanation fits.

So the preventative cure would be to put in an auxiliary electric fuel pump, yes?

I'd sure wait for it to happen again (maybe a couple of times) to give you a better chance to diagnose before you start taking action.

I've never had an electric fuel pump on any stude (over 30 now). Never any vapor lock either. Also, never any problem running E10 with a carb (as long as the soft parts in the fuel system were upgraded to modern ones)...these results across not only the Studes I've owned but also a variety of vintage brand X's in all kinds of temps up to 100F in Arizona and the midwest. Your results may be different of course.

There are so many things it could be...stuck closed float, dirt under float inlet valve, high float level, "fuzzy" ignition switch, bad ground or other connection, coil going bad, intermittent short in dizzy, high tension lead from dizzy to coil not fully seated, etc.

BTW, it doesn't sound like vapor lock to me if the car immediately restarted. From what I've heard, with vapor lock you have to wait for things to cool down for the car to run again.

[showbizkid]

Yeah, I guess maybe one occurrence isn't cause to panic I'll see if it happens again. Weather's warming up!

I think I can rule out the ignition switch, though - I replaced that with a new SI part a year ago.

[warrlaw1]

Possible bad cell in a battery...could be a warning. How new is your battery?

[dictator27]

I've had that happen with a bad condenser. The engine would just shut off when idling, but would restart immediately.

Terry

[55 56 PREZ 4D]

As a preventative measure until or if it happens again.
Check ALL your electrical connections.
All wire terminations, all wiring for internal corrosion.
Clean, rust free, oil and grease free, paint free.
Check tightness.
The ignition switch in my 55 is a replacement [S I ?] and needs to be wiggled a little sometimes to make contact. Better yet needs replaced.
I had a Jeep that would quit when it warmed up. Turned out the coil would create an open. Ran fine until it got warm. Replaced it and problem disappeared.
Check out Paul Kellers post about his regulator connections and his electrical problems.
They weren't the same as yours but they were connection problems.

[brian6373]

I'm with Dick on this, wait and see if it does it again. It might give you a better handle on what's going wrong. Also I wouldn't rule out the new ign. switch so fast. I've gone round and round trying to figure out a fault because I KNEW that some part couldn't be the problem, 'cause it's new.

[Milaca]

How low was the car on fuel before refilling? Do you know how many gallons of gas you put in it?

[showbizkid]

I've had that happen with a bad condenser. The engine would just shut off when idling, but would restart immediately.

Yeah, could be. It's easy enough to check... guess I'll unlimber the multimeter and see, thanks.

How low was the car on fuel before refilling? Do you know how many gallons of gas you put in it?

Sure, I put in 12 gallons. Should've had another 6 in the tank at that point.