Electrical Problems....I Think

[mapboy]

I've got this 75 FJ40 (2/75) and I can't get it started. If I jump the + end of the coil to the battery post it fires right up and keeps running until I remove the jumper wire. When key is in the ON position, I have current to coil.

This is what I've done/checked so far:
1. new ignition lock
2. new ignition wires
3. checked fuses and wires between fuse panel and coil
4. checked for clean, solid ground wires
5. checked for clean, solid battery posts and starter post


Any suggestions will be helpful and appreciated. I'll be eagerly awaiting replys from those of you who know about eletrical type of stuff. I'm more mechanical...if it moves, I can fix it. Until then, I guess I'll go check the tire pressure and see if that helps

 

[Poser]

Welcome mapboy...


Figure out why you do not have power from the start spot on your ignition switch to the coil...

Poor connection in the switch to the harness?

"new ignition lock"

Is this the 'key' part or the electrical switch assembly inside the column?


Do you have an ohm meter? (multimeter?)

You could check for continuity between the battery side of the ign switch and the start side by unplugging the switch from the main harness and connecting the leads of the meter to the points on the switch harness, and looking to see if the meter moves when the key is in the 'start' position...


Klear as mudd?


Good luck!


-Steve

 

[mapboy]

I replaced the "key" part of the switch and the wires that plug into it and run down the column to the main wiring harness.

How can I get juice to the wires if I unplug them from the main wiring harness. The ignition wires are bundles and only have one connector for the wiring harness. If I disconnect it, what will the ohm meter have to read? Any suggestions?

 

[Poser]

check your pm...

 

[Pin_Head]

The fact that it is fine when you hot wire it suggests that with the igntion on, you have voltage at the coil, but not enough current to run. This would indicate that you have a bad connection, bad wire or some other high resistance point in the circuit.

Measure the voltage at the coil + post with the points open and closed. If the voltage is substantially lower witht he points closed ( say 6 V), then there is a bad connection. With the points closed and the key on, keep following the ignition circuit (black/yellow stripe wire) back to the key, measuring the voltage at each connection. If the voltage jumps up to 12 V, the bad conncetion is between the two test points where the voltage rises.