Starts as soon as you connect the battery

[Do Over]

Been working for months on a 69FJ40. Time spent correcting a lot of age and PO issues. Today I had the battery disconnected so I could finish installing new fuel tank and remove the rear heater. I reconnected the battery. When I turned the key the engine cranked but wouldn’t stop when I turned the key off. Disconnected the battery, lubricated the ignition switch but same problem when reconnecting the battery. Tried a different key to no avail. My gut tells me the ignition switch has failed. Am I on the wrong track. Thanks in advance.

 

[MoCoNative]

I had a starter hang up, (twice actually) it was a bad ground situation. If the resistance to ground is high through the starter contacts, they will weld themselves together. Clean up all the battery cables and make sure you have no resistance from the starter ground strap back the battery. I ended up running all the ground cables to one bolt, stock has the engine/starter grounded to the frame, and then the battery cable goes to the frame and relies on the frame and clean bolt heads. Well rust and corrosion happens.

You can probably salvage the starter, it may un hang once the cables are good. Otherwise may have to open the end up and clean up the copper contacts.

The igintion switch is simple, a test light will tell you if power is going between the key positions when it should not. There is 4 wires as I recall, one is power off the battery, one feeds the ACC stuff, one feeds the coil for run, and the last one as the key turns temporarily sends power to the starter relay. If you turn the key to "ON" and you have power to the last wire lug, then switch no good.

I'm betting bad grounds, or a weak battery.

 

[Do Over]

I had a starter hang up, (twice actually) it was a bad ground situation. If the resistance to ground is high through the starter contacts, they will weld themselves together. Clean up all the battery cables and make sure you have no resistance from the starter ground strap back the battery. I ended up running all the ground cables to one bolt, stock has the engine/starter grounded to the frame, and then the battery cable goes to the frame and relies on the frame and clean bolt heads. Well rust and corrosion happens.

You can probably salvage the starter, it may un hang once the cables are good. Otherwise may have to open the end up and clean up the copper contacts.

The igintion switch is simple, a test light will tell you if power is going between the key positions when it should not. There is 4 wires as I recall, one is power off the battery, one feeds the ACC stuff, one feeds the coil for run, and the last one as the key turns temporarily sends power to the starter relay. If you turn the key to "ON" and you have power to the last wire lug, then switch no good.

I'm betting bad grounds, or a weak battery.

 

[Do Over]

Thanks for the feedback. Put battery on charger for full charge. Cleaned grounds on solenoid, frame and engine including chasing threads, polish fittings and dielectric grease. Removed ignition switch and checked for shorts and cleaned all connections (plenty of rust). Problem not fixed. Even tried the ‘67 Chevy truck fix of hammer taps to the solenoid. No go.
If I remove the starter switch and connect it to a separate battery, the solenoid connection test should work, right?

 

[Do Over]

It is the ignition switch. The black-white terminal wire which runs to the starter solenoid is energized even when the key is not in the ignition which explains why it tried to start as soon as I hooked up the battery.
Thank you very much.

 

[MoCoNative]

Do you have the connections correct at the battery? Starter? That wire can only get power from the switch. Is it getting power with the ignition switch unplugged from the harness? I would think it odd that the switch would fail that way. Just want you make sure you don't have a cross connection somewhere else.

 

[Do Over]

Do you have the connections correct at the battery? Starter? That wire can only get power from the switch. Is it getting power with the ignition switch unplugged from the harness? I would think it odd that the switch would fail that way. Just want you make sure you don't have a cross connection somewhere else.

Thanks for sticking with me. Electrical is way outside my wheel house. Earlier today I took the ignition switch out , taped over the leads, touched the negative clamp to the battery and the starter turned over. Next I took the white wire off the solenoid, put the positive battery lead back on and the starter did not turn over. Could the magnetic switch in the solenoid be shorted?

 

[mtquivr]

It's been 30 years or more since I took apart a starter, so I may be confusing things a bit. There are contacts in the solenoid and when you use the starter, they can arc, creating pits. They can stick together causing your problem. IIRC, you can disassemble the solenoid and reverse the contacts gaining new surfaces.

 

[MoCoNative]

Yeah wiring can be really frustrating. You have to get in the right mindset to follow it through and work it out. I looked a little bit yesterday at starter wiring. Coolerman on this board is the resource you need for your early wiring harness. I included the link to his website and a wiring diagram for your truck. I saw where he mentioned that the large white wire in pre 71 went to the starter. This large white wire is the main charging wire from the alternator, to the amp meter in the dash to the starter. From there the charge goes up the big red lead to the battery. Later models ran that wire straight to the battery with a fusible link that helped protect the wiring harness from overload. May be worth the change and upgrade. According the diagram, that white wire is spliced into under the dash, covered, to feed two fuses on the fuse block and to also run to the hazard switch which is fused seperately if you have it. The two fuses look to be Horn and Headlight I suspect. This wire is where the truck should get all of its power. If it is hot for some reason there is another power wire coming off the battery somewhere.

Had another thought, is your starter wired like the picture below, because if you have the big red lead and white wire to the same lug as motor run wire, it will make the motor spin when you hook it to the battery. This would bypass the selenoid. I can't quite tell from your picture. Is the starter motor spinning, or is the engine actually turning over continuously. I think having the battery cable wrong here will spin the starter motor, but the solenoid will not engage unless power is fed to the start terminal to make the magnet energize and activate the solenoid. This makes contact internally to run the starter motor, but it also pushes the starter gear out to engage on the flywheel. If you don't have flywheel engagement, but starter motor is freely just spinning, than that is probably what is going on. Simply swap to the other bolt and see what it does.

Cruiser Wiring 1969 wiring diagram from Coolerman

 

[peesalot]

Yes, the contacts in the solenoid can become constant due to corrosion, part failure, etc.
But, that should not cause the constant power at the wrong terminal at ign. switch. I would bet that the ign switch has constant power running to the on or acc. terminal which causes the No shut off condition.

 

[Do Over]

Yeah wiring can be really frustrating. You have to get in the right mindset to follow it through and work it out. I looked a little bit yesterday at starter wiring. Coolerman on this board is the resource you need for your early wiring harness. I included the link to his website and a wiring diagram for your truck. I saw where he mentioned that the large white wire in pre 71 went to the starter. This large white wire is the main charging wire from the alternator, to the amp meter in the dash to the starter. From there the charge goes up the big red lead to the battery. Later models ran that wire straight to the battery with a fusible link that helped protect the wiring harness from overload. May be worth the change and upgrade. According the diagram, that white wire is spliced into under the dash, covered, to feed two fuses on the fuse block and to also run to the hazard switch which is fused seperately if you have it. The two fuses look to be Horn and Headlight I suspect. This wire is where the truck should get all of its power. If it is hot for some reason there is another power wire coming off the battery somewhere.

Had another thought, is your starter wired like the picture below, because if you have the big red lead and white wire to the same lug as motor run wire, it will make the motor spin when you hook it to the battery. This would bypass the selenoid. I can't quite tell from your picture. Is the starter motor spinning, or is the engine actually turning over continuously. I think having the battery cable wrong here will spin the starter motor, but the solenoid will not engage unless power is fed to the start terminal to make the magnet energize and activate the solenoid. This makes contact internally to run the starter motor, but it also pushes the starter gear out to engage on the flywheel. If you don't have flywheel engagement, but starter motor is freely just spinning, than that is probably what is going on. Simply swap to the other bolt and see what it does.

Cruiser Wiring 1969 wiring diagram from Coolerman

View attachment 2349904

In my photo, the red and white wires are on the same terminal. I put a Coolerman fuse on the white wire.These two wires are not on the terminal that has the ground connection to the starter case. The blade connector on the starter has a Black/Yellow wire that is connected to the coil. I have reviewed two schematics and I don’t see this setup anywhere. I have a B/Y feeding a fuse block, coming from the ignition switch. The wires on the fuse block match the schematic. My schematic shows a B/W wire from the ignition switch to the coil. I have a B/W on the ignition switch but am having difficulty determining what it is connected to. It is definitely not on the solenoid.
When I got the truck, there were a number of loose wires and most lights and signals didn’t work. In straightening out those issues, I may have become part of the problem because the truck did run when I got it. On the other side of the coin, all of the lights and signals now work.
I am going to try a temporary wire from the ignition switch to the coil and another temp to the solenoid from the ignition. The going is a little slow because I had rotator cuff surgery ten days ago and everything is one arm. If the temporary wiring doesn’t isolate the problem, I will have to pull the starter but that will have to wait a few weeks.

 

[MoCoNative]

The little heavy gauge jumper wire from the solenoid to the starter motor is the positive to the motor. Starter ground was from the mounting bolt on the bellhousing over to the frame originally.

I don't know if the early cruisers ever had the jumper wire from the solenoid to the coil ballast resistor. I don't see it on any diagram pre 73/74. It was used to aid starting, but I never found it to do much. My April 1973 FJ40 had it. The Haynes 1974 diagram shows it, while the 73 diagram does not. It is shown as B/W. In fact I have to use the 74 diagram alot, as the 73 does not show all the emissions wiring on my 73, go figure. You don't need a wire from the starter to the coil. Also it was pretty universal for the entire run of the 40 that the B/W went from the Start position on the ignition switch to the starter solenoid and the B/Y goes from the "On" position to the coil + and or to the ballast resistor and then coil +. The coil negative is all black and just goes over to the distributor. What else is hooked to the coil? I suspect you have another wire hanging around there that needs attached. Although the wire you have attached to the starter in your picture looks like the correct B/W wire, are you sure of the color.

It really could be as simple as bad contacts. But sounds like you are on the right track, you are almost there.

 

[Do Over]

The little heavy gauge jumper wire from the solenoid to the starter motor is the positive to the motor. Starter ground was from the mounting bolt on the bellhousing over to the frame originally.

I don't know if the early cruisers ever had the jumper wire from the solenoid to the coil ballast resistor. I don't see it on any diagram pre 73/74. It was used to aid starting, but I never found it to do much. My April 1973 FJ40 had it. The Haynes 1974 diagram shows it, while the 73 diagram does not. It is shown as B/W. In fact I have to use the 74 diagram alot, as the 73 does not show all the emissions wiring on my 73, go figure. You don't need a wire from the starter to the coil. Also it was pretty universal for the entire run of the 40 that the B/W went from the Start position on the ignition switch to the starter solenoid and the B/Y goes from the "On" position to the coil + and or to the ballast resistor and then coil +. The coil negative is all black and just goes over to the distributor. What else is hooked to the coil? I suspect you have another wire hanging around there that needs attached. Although the wire you have attached to the starter in your picture looks like the correct B/W wire, are you sure of the color.

It really could be as simple as bad contacts. But sounds like you are on the right track, you are almost there.

The magnetic switch in the starter solenoid was shorted out. Because the starter looked like it came over on the Mayflower, I replaced rather than rebuild. Corrected some wire issues, replaced the worn out ignition switch and it starts the best has since I bought it. Thanks for the help.

 

[MoCoNative]

Good to hear, glad you got it worked out