I have a 73 coupe that I replaced a 350 with a 454. Last week it stopped wanting to start. I checked the battery and the starter, both check GOOD.

I then checked the wires (battery to starter)to see if they were hot. One of the thin ones that connects to the silinode was not getting an thing.

My question now is what should I check next. I want to trace the wire, but its all wrapped up with several other wires in black tape.

I was thinking about replacing the ignition switch. Is this part easy to find and replace?

am i looking in the right direction?

thanks for any help.

 

I'd advise checking things, not just replacing things. The heavy battery and ground cables first. They can show continuity, but still not pass enough amperage to turn the motor if the connections are not clean and tight. The engine ground strap is important. As for other wires, an assembly manual will show you their routing, so you can check that they are not broken or grounded by testing at both ends without having to follow the entire length of the wire. God bless, Sensei

 

Sounds like the fusible disconnect on the hot side of the starter/solenoid might have let go

 

Are you saying the solinode may be bad? that's an easy change

 

I'm very bad at electrical problems, do you think the solinode may be bad and I should look into that?

Jut to give you a little history of the car it had a 350 but I replaced it with a 454( because I was told it had matching numbers, but it didn't).

the motor has been worked up to about 450 horse power, so it may need a better starter.

I bought a newer starter, one of the small ones and it worked fine, but when the car was hot it would not start, Once the car cooled down it would start again.

I wrapped the headers near the starter but that didn't help. I have not been able to locate a heat shield for the smaller starter so I bought an original one and put a heat sield on it.

it worked for a while then the car stopped starting so I had the battery checked and the starter at autozone, the tech there said both were fine.

So now I'm looking in the wiring.

 

Carsonc,

Using a test light check to see that the larger red wire to the solenoid has power. It should have constant power. If the light doesn't go on then you need to check this main power line and the problem between the battery and the starter, and hopefully only there. If the light goes on then place your test light on the smaller red wire attached to the solenoid and have a friend turn the ignition switch to on. Your test light should come on. If it doesn't then connect up a remote starter switch to the terminal where the larger red wire is connected and then to where the smaller red wire is connected. Turn your ignition switch to "ON" then flip your remote starter switch. Your starter should be cranking. If it doesn't but your hear something moving in the solenoid then something is probably wrong with your starter. If there is no sound then your solenoid is probably bad. Hopefully a change here will be enough. If your light doesn't go on at all then the ignition switch may not be sending power to your starter to allow the main power line to complete its circuit. From here you will at least know the problem is between the battery to the neutral safety swith (if auto), to the ignition switch to the solenoid. If you are unfamiliar with how the solenoid and starter works, how to use a test light, or remote starter then PM me and I will be glad to go into more details.

BD 06

 

Carsonc,

I reread yours and my posting and realized you have already checked the larger red wire to your solenoid and had power. You said that you didn't get power at the smaller wire. It will only be hot when the ignition is turned to "start" not "on" like I mistakenly wrote in my previous thread.

BD 06

 

The wire color for the solenoid is purple in my 68, and I think subsequent cars had purple wires for this function also.

Disconnect the solenoid wire, the one's that purple on my car. Twist the ignition key to the "start" position. 12 volts should appear at the solenoid wire. When the key is in the "run" position, there will be no voltage appearing at the purple wire.


Run position is identified as "ign" on the car schematics.
..........

This weekend I replaced the ignition switch in my 68. When I moved the key to the "ign" (run) position, the switch contacts read 300 to 800 milliohms. I measure resistance at the switch contacts themselves. This is too high of a resistance and indicates a bad switch. For example, when I moved the switch to the start position, the switch contact resistance was 1 to 3 milliohms. This was a good reading.

On the 68, to remove the switch, (after removing the speedo/tach dash panel), you have to remove the black metal bezel on the drivers side. The bezel will not unscrew until you remove the lock cylinder. Just FYI.

 

Maybe I missed it, but is this a manual or auto car? If auto then you should have a neutral safety switch that will only allow the car to be started in neutral or park. Sometimes just wiggling the shifter while having the key in 'start' will make it work. The previous posts are correct though, use a test light and make sure you are getting voltage to the sol side of the solenoid when the key is in 'start'. You can also cheat by jumping the heavy lug (Battery +) over to the 'sol' terminal to see if the starter engages.