ign problem

[geraldchainsaw 27]

today i went for a ride in the mustang,  69 mach 1, auto,  351w.     put the car back in the garage,  took a 2 hour break and wanted to go for another ride,   tyurned the key,  nothing,  no clicks, no radio, nothing, moved the shifter around,  automatic,  nothing,    went for a ride in another car,  came back got in the mustang again and it started,    any one know whats happening?,  thanks   jerry

[barnett468 418]

clean the battery terminals and where it grounds to the block first then go from there.

 

if it does it again, you can put a jumper cable from the front of the solenoid where the battery wire connects to the rear one . if it is dead, it is your starter or the cable connection on the starter . if it works, i would try a new solenoid.

[Mach1 Driver 560]

Unfortunately it could be any number of things from a bad battery to loose cables, poor connections somewhere or a bad ignition switch.

Since the solenoid didn't click and the radio didn't work it sounds like no power was getting to the ignition switch. At the least I would clean-up the battery posts then check the grounds: the big negative cable where it bolts to the block and the smaller one from the passenger side head to the firewall near the heater motor. Take them off, clean everything up, make sure you have bare metal with no paint under them and tighten all connections.

Then check the battery voltage. A fully charged battery will give you 12.6v and when the alternator is charging it should read 13.5-15v across the battery posts.

Intermittent problems are a pain. If it ain't broke ya can't fix it! If you are good with a voltmeter try tracking it down step by step through the circuit:

1. Across the battery posts:  approx. 12v You must start with close to 12v or none of the other tests may be valid.

2. Key in "start", solenoid "S" to chassis 12v. If not then B to S in ignition switch is bad or loose connection.

3. If above gives 12v at solenoid "s" but solenoid doesn't click then bad solenoid

4. Key in "on/run" position, coil "bat" terminal to chassis approx. 5.7v (stock ignition system with resistor wire, otherwise 12v)

5. If no voltage then ignition B to C circuit is open or resistor wire is open or a connection in that line is bad

6. Oh yeah I forgot to mention, if you have a tach car it must be plugged-in and operating. For some reason in these old cars, Ford decided to run the tach in series with the ignition system, not in parallel, so if the tach gets fried the engine won't run. The power comes out of the ignition switch, goes through the tach, then through the resistor wire and then supplies power to the coil "bat" terminal. Crazy.

Good luck. I can give you the wire colors if you need them it to help track it down.

 

 

 Edit: I see barnett has written a reply while I was writing mine- listen to him, he knows his stuff.

Not my thumbnails

[geraldchainsaw 27]

ok,  thanks for all the advise,  so now i have alot of trying,    one more thing,  right now it starts u[p  with no problem,    could it be some kinda heating problem?,   what ever it is,  cooled down and now works,  not saying the rad,  maybe the coil,  or what ever?,  just a thought.

[Midlife 814]

Heat can expand the battery post connector such that it isn't making good contact with the battery post.  This was on Car Talk just this morning!

[Brian Conway 264]

Neutral Safety Switch.  Next time it happens take it out of PARK and try starting in NEUTRAL.  Brian

[geraldchainsaw 27]

to Brian conway.     i tried the neutral position,  nothing,     but now it works,  so i'll go and check my connections,  clean them up etc.    wi8ll keep posted as to what happens,  thanks,   guys

[Mach1 Driver 560]

cooled down and now works,  maybe the coil,  or what ever?,  just a thought.

Since you said the solenoid didn't click, it's not the coil. Look at the schematic in the Word attachment. Power flows left to right in the schematic. The problem is somewhere in this line:

1. battery to ignition switch B

2. ignition switch S to the neutral safety switch

3. neutral safety switch to starter solenoid S.

[Mach1 Driver 560]

Its not letting me attach the Word file- lets try again:

MUSTANG IGNITION.doc

[geraldchainsaw 27]

so far it starts all the time,  but i cleaned the batt posts , cyl, both sides,  anyway,  so i guess i'll have to wait for the next time,  probly be when i'm 300 miles from home,  thanks for the adivise,   jerry