65 mustang power problem after car is warmed up. power comes and goes.

hi all,
my 65 seems to have a problem after its been driven. once its warmed up it seems to lose power after turning off the car and when i restart the power cuts off dead but will come back on again. i start the car and it runs for a few seconds then total dead no power. after a few tries at this the car comes good and off i go. sometimes when i switch the headlights on the car will die the same way. i have cleaned the ground terminal and connector. is there anything else that i should try? don't want to get stuck out and about with a dead car!!
thanks  

do you own a hand held digital volt meter... lets check the grounds... this is a jpg image just like a photo.. print it .. run the test.. post results to tests 1, 2, 3, 4..  takes under 2 minutes.. including the time to open the hood..

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1._______

2.______

3._______

4._______

this is just the beginning test... but this test has to be first so you don't chase a problem on a circuit farther on in the system..  

now that you know the voltage drop test..

you will want to also.. check the POSITIVE side...

engine running...  headlights on..  20 volt meter setting first...

positive battery post to the threaded stud on the starter relay...  this should at 20 volts DC read 0.00.. in 2 volts dc setting should read 0.01.. or actually 0.00..

i also test from the positive battery post.. to the RING terminal on the starter relay that leads to a big wire into the wiring harness.. this is the wire that supplies the car with positive..

positive battery post to the alternator output terminal... do to the amount of current passing through i expect 0.1 volts to be measured...

now... i do this a lot so i have a LONG test lead made for this next test.. but you can use if you are really careful.   a pair of jumper cables... USE only the RED side... position it so it's laying on the GROUND.. not touching the body... near the drivers door..  then hook up the other end to the positive battery...  

you can now.. again with the engine running.. measure from the end of the battery jumper cable to various fuses in the fuse box with the volt meter.. depending on which circuit you might have up to 0.25 volts.. but probably not more than that.. if you get a full 12 volts you will have found a circuit thats not powered..

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you might want to engine off.. disconnect the battery...   i usually remove it if its not fastened in too tightly...    count the wires on the starter relay stud.. take it apart and clean the ring terminals, the threaded studs and nut faces with a stainless steel wire toothbrush.  they are available in most hardware or paint stores with wooden handles for a few bucks.. really clean nicely and last for a LONG time..

chances are that you might also have a bad ignition switch...  

hi waynep
i keep my battery on a top up charger. the car starts first go all the time. i try to drive it twice 2 week.
after about a twenty minute drive. when i go to start the car again say 5 or 10 minutes later it would start easy but die after 4 or 5 seconds then completely dead no power at all. i turn the starter key off then back on again i might get power up again or sometimes not. but the car will always start again and i can drive off.
it's a bit of a worry if the car keeps playing up. don't want to breakdown.

i think it might be heat related, just a guess.  

well.. you can start replacing parts instead of diagnosing probable issues...


ignition switch... is a probable.. issue..  they do go  bad... thats why parts stores keep them in stock..




you could also have loose terminals in the ignition switch socket..




checking the voltage drop does not require anything except time unless you don't own a digital volt meter..