[Shop-talk] strange automotive electrical problem

Wed May 20 06:14:40 MDT 2026

John,

I'm a big advocate of Power Probe tools.  Here is a short circuit finder I 
have...
https://www.amazon.com/Power-Probe-PWP-PPECT3000-ECT3000-Electrical/dp/B0719JV971/ref=sr_1_6

Note, the suite of PP tools is so much more powerful then I even use.  If 
you are close to NJ, swing by and we can see what we can find if you don't 
want to dump the money into these tools <GASP>  8>)  (I did buy all of 
them because they are so helpful.)

I had a similar short on a Jeep TJ about a while ago.(before I had them) I 
gave up trying to find it, then I dropped it off at a buddy's shop and I 
challenged him to find it.  4 months later, he fix it.  It was a short in 
a wire clip.  He used the PP.

Of course if you had a new harness, that can't be the same thing, but the 
PP tools can find things that I didn't even know where issues.  It also 
help me find a ground issue on trailer lights that was completely 
counter-intuitive.

Moose

From:   "john niolon" <jniolon at att.net>
To:     eric at megageek.com, "shop-talk" <shop-talk at autox.team.net>
Date:   05/19/2026 10:02 PM
Subject:        Re: [Shop-talk] strange automotive electrical problem

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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