Hi guys, I ran into a gentleman today who has a well restored 1969 f100 with a 429/460, not sure which. Looks brand new and runs like a dream, except, at any given moment it will lose all power. I mean everything goes, engine, electrical and without any warning. Its not bogging or sputtering before it goes, it just dies. Sometimes it goes for weeks, sometimes days before it happens. It has a new carburetor, fuel pump, fuel lines, battery, alternator is good. I forgot to ask about the distribuor but assuming that is good, what would cause this issue. He thinks its fuel related but sounds pretty obvious its electrical. He wants to sell it for a price that is very hard to pass on, but I am stumped. Thanks guys.
When you say 'everything', does that include lights, horn, brake lights? Does power come back after a certain amount of time, or is it irregular?
He said power comes back after a certain amount of time. It wont start right back up. Literally everything.
Ok I thought it might be a bad ground but the wiring was all replaced he says. Would the ignition switch go out then work again after a while?
An ignition switch is prone to failing from heat from simply being used....like any electrical component. The fact that it'll work after it cools off is a typical symptom. If everything switches off like a light switch as you said...that would be where I'd look first...
If you're losing all electrical systems, I'd suspect the main power wire coming from the battery, or more likely, the starter solenoid. A bad ignition switch shouldn't affect the non-ignition-switched circuits like the horn, headlights or brake/tail lights because they shouldn't be wired through or to the switch. Start at that wires origin at the battery or solenoid and start tracing towards the fuse panel. It could also be a bad or no ground/bonding wire between the negative battery cable connection and the body steel, but I suspect that it's probably more than that. Now, the only caveat to this is if the wiring has been 'replaced' and is non-stock, it may be mis-wired so you may find something out of the 'normal'. Check for the ground wire first; if the negative cable is connected to the engine block, make sure you have at least a #10 wire between the block and the body shell for a ground. If that doesn't clear the issue, then trace the main power wire, which should also be at least a #10 wire. Look for poor connections, or possibly an in-line circuit breaker that's too small for the load.
Are the chassis and engine grounds made to good clean metal surfaces, or is it trying to ground through a layer of fresh paint?
If it's "everything " like there's no battery in the truck, then it's a problem with the battery, main cables and connections. Should be super simple to find and fix that type of problem.
It needs bigger jets. I would trouble shoot the electrical system. My first guess would be that it has bad 45 year old ignition switch. but there could be a gremlin in the system anywhere. If all you are loosing is ifnition and everything else works, IE lights, radio, and etc,and it has the later electronic distributer with the external control mod that the control mod is suspect.
All good suggestions ..... and one more .... Rewired ???? Hmmm.... aftermarket harness or just replacing SOME wires ??? If it has a FIREWALL CONNECTOR I would check that ... MANY CARS have that SAME problem due to the FIREWALL connectors being old and corroded ...
Yep I completely over looked the firewall connector. Most recently (for me) my '65 galaxie had that problem.
I can go with a firewall connector. Take a good look at both sides of the wiring, see if anything is loose, broke or green. If that looks good, hot wire the ignition switch... frig it. Replace the switch, they're cheap enough at NAPA.
IIRC, Ford didn't use those firewall connectors on the trucks until the 70s but if stuff has been 'replaced'...
Firewall connector if it has one, if not check for a loose positive post on the battery. I have seen them get loose inside the battery and cause similar problems, especially if it has a 1-wire alternator.
I'd try a few voltage drop tests before spending 5 cents on parts, or to get this guy's opinion. https://s-media-cache-ak0.pinimg.com/564x/8d/3b/4e/8d3b4eaf93b6e9cc2f622e4e5bad474f.jpg
Wow great ideas everyone! I will be checking it out tomorrow in person as all I have seen so far is pictures. I will try taking pictures and posting them on here in the next couple of days. I feel very confident that it should be a simple fix with all of your guidence. Really, really appreciate all the help.
Had an O/T car that had that problem. The previous owner who "installed" it cobbled the wires together. One was a bit short so he installed a ring end & just wrapped the extra wire around it & taped it, didn't even solder it. When I touched the wire it burst into flames, good thing the battery cable end wasn't real tight on the post!
Scary... I bought a '64 Caddy that had been wired up front with lamp cord, that one went up before I bought it.
My EZ wiring harness had the main lead from the solenoid to the fuse panel poorly crimped. I would be driving and it would all cut out. I was told a machine did the crimping, but someone had to assemble into the machine. I found it when I pulled the fuse panel and dislodged the connector from the back. The crimp closest to the lug was sposed to be bare wire, it was crimped over the insulation and the bare wire making sporadic contact with the lug. Check to see if the rewiring was a fit all harness or just hand done and recheck all of the connections at the fuse box.
Shoot, he is not able to show it today but he said hopefully tomorrow. I started asking more qjestions a d he seems less interested in selling to me now. Hmmm, we will see.
Yep, I'm sure the owner is asking folks about the issue. Once he talks to The first guy who knows a little bit, the truck will be diagnosed inside of 15 mins.
I had a battery shut off switch randomly open. Don't remember the exact symptom but if I turned it off and back on all worked. I ended up taking it off and throwing it away.
I worked on a 67 Mustang for a guy that the Ford dealer couldn't fix. The symptom was that it would die when accelerating and acted just like you turned the key off. So hooked up my volt meter to the pos side of coil and monitored it. And I would see a voltage drop. Now after chasing this for some time going to wrong direction back to the switch and the resistor and not finding the problem this little light came on in my head that the wire going to the solenoid was hooked to the coil pos side also. So I unhooked the wire at the solenoid for the 12 volt bypass a guess what it was cured. Now I had to see what was going on in that solenoid and here is what I found. There was a small peace of wire floating around inside it that would short it out when you would accelerate. Enjoy.
I think you were exactly right... I was actually outside working on my truck when he walked by to chat. I have not been able to contact since... He has probably seen me outside working on it a few times and thought he would ask. Well anyhow guys thanks for all your help but I have not been able to see the truck. Man I feel used, and not in the good way hehe.
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