[Shop-talk] strange automotive electrical problem

Thu May 21 18:44:19 MDT 2026

Ok. If it shuts down like the ignition was cut off, I'll go out on a limb
and say ... The ignition was cut off somewhere. I'd work backwards from the
cylinders, checking for single failure points. (For instance, a single bad
spark plug or secondary wire won't shut down the whole engine, but an
intermittent ground at a distributor or spark pack might just.)

Btw, is this a points engine or electronic?

________________
Sent from my phone
Best Regards,
Al Fuller

On Wed, May 20, 2026, 7:40 PM john niolon <jniolon at att.net> wrote:

> yes  Al...  it shuts down like you turned off the ignition... now a
> starving type dying
>
> as for moving the shift lever to neutral... that is the first thing done
> to keep momentum to get it off the road...  As far as going into park... it
> has never failed while sitting still or parked, it's always when moving.
>
> Jim... this is a custom street rod and other than maybe the spark control
> box not sensing enough voltage there are no other sensors.
>
> Jeff,  both us and the wiring guru have tried to check every connection
> that might be suspect and found nothing, but we're not ruling out a pin
> slipping back inside a connector like David suggested...
> I've had that happen in my truck... it was the devil to find.   something
> to check...
>
> Thanks all for the advice and suggestions guys...   I wish the dang thing
> would just fail completely and stay that way... maybe even make some smoke
> (just a little)  At least we'd have a failure point instead of
> a gremlin like this.
>
>
> *----- Original Message -----*
> *From:* Al Fuller <alfuller194 at gmail.com>
> *To:* john niolon <jniolon at att.net>
> *Cc:* <eric at megageek.com>, shop-talk <shop-talk at autox.team.net>
> *Sent:* 05/20/2026 7:39:57 PM
> *Subject:* Re: [Shop-talk] strange automotive electrical problem
> ------------------------------
> 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
>>
>>  _______________________________________________
>>
>> Shop-talk at autox.team.net
>> Donate: http://www.team.net/donate.html
>> Suggested annual donation  $12.96
>> Archive: http://www.team.net/pipermail/shop-talk
>> http://autox.team.net/archive
>>
>> Unsubscribe/Manage:
>> http://autox.team.net/mailman/options/shop-talk/eric@megageek.com
>>
>> _______________________________________________
>>
>> Shop-talk at autox.team.net
>> Donate: http://www.team.net/donate.html
>> Suggested annual donation  $12.96
>> Archive: http://www.team.net/pipermail/shop-talk
>> http://autox.team.net/archive
>>
>> Unsubscribe/Manage:
>> http://autox.team.net/mailman/options/shop-talk/alfuller194@gmail.com
>>
>>
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://autox.team.net/pipermail/shop-talk/attachments/20260521/9093d046/attachment-0001.htm>