This isn’t a Ford question… It’s a general troubleshooting question. Fellow hot rod guy with a C***y and a big block. Was running fine till it started dying on him while driving… like you cut off the switch. Get to the shoulder and it starts right up. It doesn’t stumble or stall and runs like a scalded dog when it’s right… it just dies. Might do it once a week or 5 times a day. We think we have eliminated fuel as we checked fuel flow when stopped and the squirters are working and fuel bowl is at right level. Fuel pressure is 4-5 psi on carbed engine. We even removed existing premium fuel and replaced with fresh... and the fuel filter.

We’re thinking intermittent electrical. So far he has replaced distributor with a known good one, and the coil. He’s changed to a Optima battery and new cables. Heavier ground cables to engine, frame and body. I thought about funky ignition switch making intermittent contact on coil wire… changed the ign. Switch with an oem switch. We’ve traced all the wiring that we can and find no breaks, bare wires, loose connectors..


Everything looks as it should…Battery voltage is 13+. It makes no difference what accessories are running …fan…a/c…stereo..etc.

Suggestions ? if you brainiacs can't figure this out... he should scrap it !!

 

Ignition type?

If it's a single-wire electronic I'd put a temporary switch (toggle or something) directly to the distributor.

 

If you could tell us what he is using for an igntion system that would help. Meantime I would temporarily install an aftermarket under the dash voltmeter (or even solder some wires to a small 12 volt bulb) that is connected to the + terminal of the coil. When he is driving and the engine dies have him quickly look at the voltmeter or bulb and see if the coil is getting voltage. It will probably be around 9 volts or so IF there is a ballast resistor. If no voltage there you at least know you could work your way back and make the next connection to the ballast resistor if used. Test the end that feeds the coil, (maybe a bad jumper between the coil and resistor). If you loose voltage there, next connection would be the igntion switch wire on the resistor. Just keep working your way back thru your new IGN switch. Try to wiggle the key around.( I am sure though you gone the wiggle tests aready.) How about the fuse in the circuit? I bet he is probably using an aftermarket harness along with a fuse panel. Maybe the fuse or fuse panel contacts are loose or corroded. Are the contacts on the fuse darkened?
Anyway just some thoughts. Trying to sort out what is good to get to what is bad. Hope it helps!

 

Does it just lose fire/ignition? Or is it a complete electrical shut down? From your description it sounds like the latter, which would rule out both ignition and certainly fuel, but point to a more complete but intermittent electrical failure. If so, I would concentrate the search on the supply side of power, from battery to fuse box and main power and/or ignition switch, however it may be wired. Many GM's had a common power connection on the firewall. That may be a source of a short, triggering a trip of a resetting circuit breaker somewhere in the system.

 

Well, I guess just me posting this problem got it fixed...got a message last last night with this picture



It's all crispy... was attached to the ign switch on a piggy back connector and buried up under the dash. Us portly older gentlemen have a difficult time getting in between the seat and the kickpanel and
working lying on our backs with a cramp in our leg and our neck hurts.

So far, replacing bad stuff did the trick... road test this p.m. Two car gatherings this coming weekend and we need this fixed !!!

thanks for all the suggestions and info... might help down the road with another.

john

 

Great news! Thanks for the update.

 

I'm glad he found it. Apparently problem wasn't mysterious.

 

well Abe... little mysterious... A LOT frustrating. and the devil to get to !!!

 

Had a connection that looked a lot like that on the Battery Terminal of my alternator. I wondered why my electrical system wasn't charging so well
The end of that 10 gauge wire was so burnt discolored and corroded I just replaced the whole run back to the starter solenoid, with a tap off to the A terminal on the Voltage regulator. It charges great now.
Normally this connection hides under a rubber cap behind the alternator. If I hadn't removed the alternator to change the timing cover and gaskets, I wouldn't of known that was my problem.
It might pay to look that connection over once a driving season.