[Shop-talk] strange automotive electrical problem

[Al Fuller]

It sounds like you are/have ruled out fuel starvation, indicating it has
fuel as far as the carburetor (and presumably the cylinders), and you
appear to be describing a sudden 'cut off' as opposed to the less sudden
dieing out do to temporary lack of fuel. Yes?

If so, it seems like it would need to be a fault in the ignition system
that allows spark, then changes state to deny spark, then returns to the
prior or similar state where spark gets called for, produced and delivered.

________________
Sent from my phone
Best Regards,
Al Fuller

On Tue, May 19, 2026, 10:52 PM john niolon <jniolon at att.net> wrote:

> Hey Moose, thanks for the reply.  Harness was done by a pro that does it
> for a living...He is meticulous.  He completely strips everything
> from the car then starts from a blank slate... Everything new.. Nice looms
> and grommets at every hole and hides as much of it as he can.
>
> Every component was new and oem or better... no import crap.   I'm of the
> same opinion as you afa a short to ground but it's gotta be hidden inside
> something
> that we can't see.
>
> Someone on my ford forum suggested putting a volt meter in the circuit and
> watch the voltage for a drop...but you're so busy trying to get out of
> traffic and not
> get plowed it's difficult to remember to watch the meter....   and yes
> this has been going on for over a year...intermittently and even after all
> the changes... it persists
>
> john
>
>
> *----- Original Message -----*
> *From:* <eric at megageek.com>
> *To:* shop-talk <shop-talk at autox.team.net>
> *Cc:* john niolon <jniolon at att.net>
> *Sent:* 05/19/2026 4:40:59 PM
> *Subject:* Re: [Shop-talk] strange automotive electrical problem
> ------------------------------
> John, I would have bet money it was a hidden wire short somewhere. It had
> all the Hallmarks.  But you stated the wiring harness what completely
> replaced. So, that rules that out...
>
> Or does it?
>
> My question, when you said 'headlight to taillight', that is complete.
> BUT was there ANY wire that was in that car that wasn't part of the harness?
>
> Something in dash, neutral switch, tranny indicator, or some other
> component?
>
> I'm still betting on a wire short, but I guess it could be a short inside
> a component.  Maybe inside the alt or other part?
>
> BTW, I'm assuming it was doing this, before you did all these mods, right?
>
> Anyway, that is a stumper.
>
> Moose
>
>
>
> From:        "john niolon" <jniolon at att.net>
> To:        "shop-talk" <shop-talk at autox.team.net>
> Date:        05/19/2026 13:16
> Subject:        [Shop-talk] strange automotive electrical problem
> Sent by:        "Shop-talk" <shop-talk-bounces at autox.team.net>
> ------------------------------
>
>
> Strange automotive electrical problem we need help with…
>
> 55 chevy automatic with 383 stroker motor, carbed, p/s,p/b,a/c
>
> Dakota digital dash system including neutral safety switch and
>
> Transmission gear indicator
>
>
>
> When it is running right, it’s scary strong.  Cruises nicely.
>
>
>
> Problem… when driving the engine dies like you cut it off…BUT will start
> back up
>
> Immediately and run perfectly till the next time it does it.  Might be 15
> minutes…15 days or
>
> three month later. Might do it 4 times in a row or once and not repeat.
> Speed does not effect it.
>
> Engine temp does not effect it…  does it hot or cold. With the a/c on or
> off.  It does not have a
>
> Cutoff switch in the system.  Longest period with no failure is 7 months…
> shortest was 4 minutes.
>
>
>
> When it stalls we checked fuel by looking in the bowl of carb and gas is
> spraying as it should
>
> So we are assuming electrical of some sort.  So far we’ve done the
> following…
>
>
>
> Replaced battery with new red top optima battery and all new battery
> cables (2 gauge I think)
>
> Replaced all ground cables frame/block… frame/chassis with 2/0 welding
> cable with new crimped
>
> connectors and clean, bare metal attachment points
>
> replaced ignition switch (twice… first with import then with oem switch)
>
> replaced coil and distributor with MSD system with spark control box,
> separate coil and distributor…
>
> it was taken from running vehicle.  It's doing the same  thing as the
> original ignition system.
>
> Replaced complete wiring harness…headlight to taillight with new Autowire
> harness…including all
>
> Switches and relays. Professionally done.
>
> Everything else electrical works without a glitch…  we are at the wall
> here…
>
>
>
> Ideas, suggestions, calculated wild a** guesses welcomed…
>
> thanks
>
>
>
> john
>
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