I have a 1977 f-150, 460, auto trans. It starts just fine when it's cold. After it has been running and warmed up, it will not start with the key ignition. I can jump it off the starter solenoid though. I've replaced the solenoid, still the same issue. Any ideas? Thanks in advance for your help!

 

Can you give more details on what it is/isn't doing and what you've tried?

"It will not start" - will it crank over and just not fire, or does it not turn over at all?

"jump it off the starter solenoid" - what did you jump? Battery to the terminal from the ignition switch that engages the solenoid? Battery straight to starter? Something else?

 

Won't start as in "nothing" from the key, no cranking, ect. after the truck has been warmed up. I jumped it from the battery side to the terminal with the ignition switch on the solenoid. I talked to a guy the other day and explained the problem to him. He suggested that it might be the ignition box that is bolted on the side of the fender, or possibly a bad coil that quits working correctly after heating up??

 

If it were the ignition module or the coil, it would crank but not fire - those are likely culprits in such a circumstance. But in your case, if it's not cranking at all, that's odd ... does it always do this when warmed up, or intermittently?

Some troubleshooting steps (when it's acting up):
1. Check to see whether the start signal is getting to the starter solenoid from the switch - does it have 12V with the switch in the start position?
2. Check the voltage at the ignition switch - does it have 12V:
a. Coming to the switch from the battery?
b. From the switch to the appropriate wires in the start & run positions?

If there's no voltage to the switch, I'd suspect one of the fusible links under the hood where it connects to the battery side of the solenoid.
If there's voltage to the switch, but not through it, the switch is bad.
If there's voltage through the switch, but not to the starter solenoid, the problem lies in between - possibly the neutral safety switch on the transmission, or wiring...
If there's voltage all the way through to the solenoid, but it's not doing anything, then either the solenoid is bad or there's a bad wire/cable; the fact that you can jump it at the solenoid makes this situation unlikely.

 

It seems to only do it when the truck is warmed up and driven. When it's cold or has been sitting, it starts just fine and acts normal. Thank you for the troubleshooting steps, I'll definitely look into those. At first, I thought it might be the Neutral Safety Switch, but when it started after sitting for a few days, I thought maybe not. Anyways, thanks for the help!

 

I guess my first question was intended to be: does it do it every time when it's warm, or only sometimes but never when it's cold?

I don't have a definitive answer either way, just wondering. My guess would be either a fusible link or the NSS is doing something weird when hot, but there could be something else I'm missing. Will be interesting to see how your troubleshooting goes.

 

when my ignition module went out, the truck would just die and would not crank back up until it cooled off. not sure if this is what is happening to you.

 

Seen that happen a lot, but in his case it's not cranking on the starter at all. No click, no crank, no nothing. If it's anything to do with the ignition module the engine might not start, but the starter will still crank the engine.

Paul

 

Do you have headers?

Where are your grounds? Make sure the contact points are nice and clean. I'd check over your wiring in the engine bay over for any damage.

Don't discount that the new solenoid could be faulty.

A few pics of the engine bay, maybe the new solenoid and starter might help someone see something.

 

FYI, necrothread...

 

Fooled again!

 

sorry paul, i missed read you post.