Wiring problem. Car won't turn over at times

[Topless69GT 28]

I started driving my Mustang yesterday for the first time on the road. What is happening is that when I get in the car it fires right up and drives wonderful. After the car is warm and I go somewhere and shut it off it will not turn over? I was thinking it was a neutral safety switch issue (FMX trans). I unplugged the 4 plug connector and plugged it back in and it fired right up. I got home cleaned up the terminals and applied dilelectric grease. Thought it was fixed. It happened later in the day again. This time I had to let the car sit for a while and then it fired up (thankfully it was in my driveway). After thinking about it  I unplugged the neutral safety switch wire harness and made a jumper wire. The car fired right up. It appeared that this fixed it and the problem was the neutral safety switch. However it is doing it again with the jumper wire in place and the neutral safety switch harness unhooked.

 

Not sure what is going on. Could it be the ignition switch? It appears to only happen when warm and happens every time I shut it off.  

[det0326 179]

I started driving my Mustang yesterday for the first time on the road. What is happening is that when I get in the car it fires right up and drives wonderful. After the car is warm and I go somewhere and shut it off it will not turn over? I was thinking it was a neutral safety switch issue (FMX trans). I unplugged the 4 plug connector and plugged it back in and it fired right up. I got home cleaned up the terminals and applied dilelectric grease. Thought it was fixed. It happened later in the day again. This time I had to let the car sit for a while and then it fired up (thankfully it was in my driveway). After thinking about it  I unplugged the neutral safety switch wire harness and made a jumper wire. The car fired right up. It appeared that this fixed it and the problem was the neutral safety switch. However it is doing it again with the jumper wire in place and the neutral safety switch harness unhooked.

 

Not sure what is going on. Could it be the ignition switch? It appears to only happen when warm and happens every time I shut it off.  

when it gets warm and won't start does it seem like it is completely dead or does it turn slowly

[Topless69GT 28]

Nothing happens when you turn the key. Just like if you were to try and start you car with it in drive. Starter does not turn at all. The starter is a standard type starter from NAPA nothing fancy.  Not sure if heat has anything to do with it but it

 

sure seems to happen when it is warm.

[LoneWolf2U 136]

Next time this happens, Remove the r/b wire from the "S" post. Use jumper wire from Batt side to "S" post. Does starter turn over the engine?  Yes... Sol functional.

No check sol connection and grounds.

If the sol functions correctly,  Next with r/b off "S "post, use test light or volt meter to see if there is voltage to wire end when key turned to start position. No voltage appears check wie and connections back to ing switch.

[det0326 179]

 

Nothing happens when you turn the key. Just like if you were to try and start you car with it in drive. Starter does not turn at all. The starter is a standard type starter from NAPA nothing fancy.  Not sure if heat has anything to do with it but it

 

sure seems to happen when it is warm.

 

While it could be cable connections at battery or sol. or ground at engine, I had a similar problem once on a re-manufactured starter and found that one of the brushes was sticking in the holder and found that when it got warm and would not start I could tap on the starter with a hammer and it would then start turning again. This of course is if all the wiring was making good connection.  I also would suggest when it happens again to turn on your head lights and see if they are functioning properly.

 

Dave  

 

Edit     

You said tho that it was just like trying to start in drive with no sol. clicking or anything so the brush sticking would not be your problem because sol. on mine would also click but starter would not turn. When it does it again tho I would still check headlights to see if you are getting power from battery.

[mustangmike6996 34]

I have a reman starter in my car and If I get it at the top of a compression stroke sometimes I have to bump the key over to get it to turn the starter. 

[69mi 10]

Try tapping on the starter solenoid. They can get stuck.

[70769 18]

i had a wierd issue like that before as well. turned out it was my engine ground. just enough resistance when it was hot and it wouldnt start. plus it melted my alt harness. good luck!

[shaun071 62]

I usually run a relay in the starter circuit as it takes the load off the ignition switch. Most old Fords I've owned have developed the same issue you have and the relay fixes it.

[blueblood 26]

I had the same issue on my '70.

I added an addition engine to body earth (battery cable size wire) which cured this issue.

[mustangmike6996 34]

Yea, I forgot to add that I ended up adding a ground strap from the engine to the firewall

[Topless69GT 28]

I went out to start working on this problem today and the car will no longer start at all. Tried to jump start it and I swapped out the solenoid, had the starter and battery checked out at the auto parts store and they are good. It now clicks when you turn the key but does not turn the car over. I double checked the grounds and they are good. Changed out the cable from the solenoid to the starter. Still same deal just a click. Neutral safety switch is by-passed with a jumper wire so that should eliminate that as a potential problem.

[shaun071 62]

About the only thing left in the circuit is the ignition switch itself. The internal contacts can wear and crud up over time.

[Topless69GT 28]

Ignition switch is less than a year old as well. I am really frustrated with this car and I am starting to hate it. It seems to be a constant source of stress and issues.

[69mi 10]

Will it turn over when you hot wire it?

[det0326 179]

These old cars can be frustrating sometimes they seem to store up a wealth of problems. It just takes time to work through them. You say that your sol is clicking so I would think your ignition switch is OK and you had your starter and battery checked. Your local auto parts store may have very experienced employees working there I don't know but around my area the part stores have kids working there that don't have a clue. If you haven't done so I would put that battery in a car that has no problem and see if it will start it then you will know for sure. If it does start then you need to start looking at cable connections .   You say The sol clicks is it one clean click while you turn the key and hold it or does it seem to buzz and vibrate? If it buzzes and vibrate that is a sign of it not getting enough current .

 

Have you cleaned and checked negative battery cable where it connects to engine block? 

 

Dave

[Topless69GT 28]

Finally got it fixed. Both of the Auto Zone remanufactured starters were junk. I finally grabbed the old rusty looking one that I pulled off the car 5 years ago when I started the restoration. I put it on the car and it fired right up and the car started after it was warm. Both problems solved with my old crusty original starter being put on the car. I will pull it off next weekend and detail it so it looks nice. The parts being sold as remanufactured these days seem to be junk. I don't recall having these issues in the 80's and 90's with remanufactured parts.

[JayEstes 172]

wow.  That is amazing.  It's called "china" - that's where we get everything now, and the stuff looks great, but is just so freaking unreliable or substandard.  I try to stick to buying American made parts (&tools) these days, but a) I usually can't tell if a part is US made or not, or b) I can tell but the American made costs and arm and leg, or c) they just don't make it here anymore.  US made stuff is built to standards, import crap is built to lowest cost..