Starting issue Options

[Geezer914]

Spent the day at the Millville NJ race track today 85 degree weather. Went to start the car at 5pm and nothing happened. Battery is good, turn the key and nothing, no clicking or anything. Gauges work, gas gauge etc. The guys gave me a push start and it started, drove home for 45 minutes with no problem. Pulled into the garage, shut it off, turned the key and it started! I have the Ford 6 volt starter solenoid installed between the starter and the ignition switch. So where do I start? Being it started, I can't trust the car starting if I stop somewhere and shut it off. WTF?

[Superhawk996]

I’ve drawn the schematic your car as you’ve laid it out. I’ve simplified the yellow solenoid wire by omitting the relay board pass through. Likewise I’ve omitted a 2nd hot start solenoid.

By adding in the disconnect switch, that adds at least one more ground cable. #1 cable goes from the battery negative to the switch, and then a new 2nd cable from the switch to the body. Generally speaking this is bad design practice. You want to keep the ground cable from the battery to the body as short as possible. That’s why the OEM chassis ground point is right behind the battery and is brazed in to assure a good electrical connection to sheetmetal.

The bottom line is that if the switch and ground cables are quality parts, they really should have no effect on the reliability of your chassis ground. However if they have too much resistance in any of the parts or the connections between them, this is going to make any potential hot starting issues worse.

I’m not sure if this helps you to visualize what is going on, but the bottom line is that with the disconnect switch and the Ford Hot Start relay, you are only adding in more complexity and electrical connections that could impair reliability.



We can use or revise this schematic if you decide to continue to troubleshoot after you install the new hot start relay.