71 Mach shut down

sca5234 · Aug 18, 2024

I'll preface by saying I'm quite the novice mechanic. Car was running perfectly fine during a normal weekend drive till I got 100 yards from the house and it just completely shut off.

Nothing happening when turning the key over besides the occasional flash of the radio

After pushing it in I'm trying to figure out exactly where should I start. I took the battery to get checked by AutoZone and O'Reilly's today both said it was fine

when I hooked everything back up and cleaned up some terminals I still got the occasional flash of the radio.

But when I put the battery charger on it the radio stayed on and any additional trying of starting or trying to cut the lights on results in it going black again

Battery issue? Grounding? Starter solenoid? Ignition switch? Have to get a volt meter tomorrow as I can't find mine so some of these I couldn't test .
Any help will be appreciated! Included some pictures of the solenoid and everything just to see if something looks off

giantpune · Aug 18, 2024

I wouldn't think it would be the battery. Even if the battery is crap, once its running, it'll keep running if you take the battery out and toss it in the river. If everything is working correctly, the alternator will keep it running.

I guess the cheapest and easiest is to look at all your connections for lose connections and/or something shorted. I see you have a bunch of home-made wires with hand-crimped ends. One of those could have come lose. And if you have a set of jumper cables or a battery in a different car, you can rule out a bad battery. I'd hook it up to a different car and see if it tries to crank.

Mac · Aug 18, 2024

sca5234 said:
I'll preface by saying I'm quite the novice mechanic. Car was running perfectly fine during a normal weekend drive till I got 100 yards from the house and it just completely shut off.

Nothing happening when turning the key over besides the occasional flash of the radio

After pushing it in I'm trying to figure out exactly where should I start. I took the battery to get checked by AutoZone and O'Reilly's today both said it was fine when I hooked everything back up and cleaned up some terminals I still got the occasional flash of the radio.

But when I put the battery charger on it the radio stayed on and any additional trying of starting or trying to cut the lights on results in it going black again

Battery issue? Grounding? Starter solenoid? Ignition switch? Have to get a volt meter tomorrow as I can't find mine so some of these I couldn't test .
Any help will be appreciated! Included some pictures of the solenoid and everything just to see if something looks off

Very simplictly, these cars need two things to run; spark and gas. You can look down your carb after you remove the air cleaner and pump your accelerator linkage and you should see two small streams of gas squirt. If there, now you can focus on electrical.
Pop your distributor cap and trip your solinoid and look to see if your points have a strong spark and not locked closed. Double check that you have a ground strap from back of passenger side head to fire wall.

sca5234 · Aug 18, 2024

giantpune said:
I wouldn't think it would be the battery. Even if the battery is crap, once its running, it'll keep running if you take the battery out and toss it in the river. If everything is working correctly, the alternator will keep it running.

I guess the cheapest and easiest is to look at all your connections for lose connections and/or something shorted. I see you have a bunch of home-made wires with hand-crimped ends. One of those could have come lose. And if you have a set of jumper cables or a battery in a different car, you can rule out a bad battery. I'd hook it up to a different car and see if it tries to crank.

I agree I bought this car from a electrician who decided to make this a living nightmare for me I've included some pictures of the before when I got it to trying to narrow down the headache to what I have now. It's been running great for months just decided to have this episode and I'm just trying to figure out where to start but I agree probably more it's probably in this over complicated mess

sca5234 · Aug 18, 2024

Mac said:
Very simplictly, these cars need two things to run; spark and gas. You can look down your carb after you remove the air cleaner and pump your accelerator linkage and you should see two small streams of gas squirt. If there, now you can focus on electrical.
Pop your distributor cap and trip your solinoid and look to see if your points have a strong spark and not locked closed. Double check that you have a ground strap from back of passenger side head to fire wall.

Carb is doing it's thing. I'm trying my best to locate this ground strap right now

TheDude · Aug 18, 2024

Yeah, if power to the whole car is blinking off and on as you see with that radio, sounds like maybe the ground is very loose or not connected or the same thing on the positive side. If you have a test light or multimeter, I'd work my way out from the battery and see what has power and what doesn't. That wiring on the fender well might be a bit challenging to sort out but if all power is blinking off and on for everything, it should be pretty close to the connections to the main + or - of the battery I'd think.

Hemikiller · Aug 18, 2024

Looks like you have aftermarket battery cables, which means the factory battery to chassis ground is no longer present. These cars did not use the head to firewall ground strap. The factory negative cable had a strap that attached to the fender apron by the lower fastener (of the no longer present) voltage regulator. Add a heavy gauge cable from battery (-) to the fender apron.

cv_72mustang · Aug 18, 2024

What is all that stuff under the mat? Any ideas? Guessing it has been removed? The PO ain't wiring my house!

detritusmaximus · Aug 18, 2024

cv_72mustang said:
What is all that stuff under the mat? Any ideas? Guessing it has been removed? The PO ain't wiring my house!

Looks like maybe headlight relays and circuit breakers. I wonder if it has upgraded halogen headlights?

In the pics I see the electric fans (if not relays for headlights, maybe for the fans?) and it looks like a relay for the ignition.

Could be too much electrical draw over the weekend.

giantpune · Aug 18, 2024

sca5234 said:
I agree I bought this car from a electrician who decided to make this a living nightmare for me I've included some pictures of the before when I got it to trying to narrow down the headache to what I have now. It's been running great for months just decided to have this episode and I'm just trying to figure out where to start but I agree probably more it's probably in this over complicated mess

Your after pictures in the OP look like you're missing the voltage regulator. Did he do some sort of 1-wire alternator setup or a 3g swap?

Don C · Aug 18, 2024

Looks like the mat covers up quite a hornet's nest. It looks like you have a PowerMaster one-wire alternator. The distributor appears to not be the stock distributor. Is that the ignition box on the top of the radiator? If so, that may be the source of your problem, bad wiring and overheated ignition box. I'm guessing (betting) the previous owner didn't have a clue about wiring a vehicle.
I agree with other posts, I would start by checking grounds, make sure the fender apron is grounded, and then a ground from the fender apron to the engine block. Even though not stock, I like having the ground strap from the engine block to the firewall. Too many chances for ground connections through the sheet metal and chassis to have become corroded. When I'm done with my build I'll have 10-gauge ground wires running to the dash and to the trunk area for good grounds for the taillights and gas tank.

sca5234 · Aug 19, 2024

cv_72mustang said:
What is all that stuff under the mat? Any ideas? Guessing it has been removed? The PO ain't wiring my house!

All that has been removed after a long tedious stint. This guy went absolutely bonkers on wiring adding fans, jump start mechanism under the hood, to kill switchs to whatever else that I had to remove from the unnecessary things he did

sca5234 · Aug 19, 2024

giantpune said:
Your after pictures in the OP look like you're missing the voltage regulator. Did he do some sort of 1-wire alternator setup or a 3g swap?

Yes voltage regulator is gone after the one wire alternator swap

sca5234 · Aug 19, 2024

Don C said:
Looks like the mat covers up quite a hornet's nest. It looks like you have a PowerMaster one-wire alternator. The distributor appears to not be the stock distributor. Is that the ignition box on the top of the radiator? If so, that may be the source of your problem, bad wiring and overheated ignition box. I'm guessing (betting) the previous owner didn't have a clue about wiring a vehicle.
I agree with other posts, I would start by checking grounds, make sure the fender apron is grounded, and then a ground from the fender apron to the engine block. Even though not stock, I like having the ground strap from the engine block to the firewall. Too many chances for ground connections through the sheet metal and chassis to have become corroded. When I'm done with my build I'll have 10-gauge ground wires running to the dash and to the trunk area for good grounds for the taillights and gas tank.

Yeah I was showing someone what the before looked like when I first bought the car. it was overwhelming. Currently there is a ground going from the battery to the engine block. Do I need to change that to the

Hemikiller said:
Looks like you have aftermarket battery cables, which means the factory battery to chassis ground is no longer present. These cars did not use the head to firewall ground strap. The factory negative cable had a strap that attached to the fender apron by the lower fastener (of the no longer present) voltage regulator. Add a heavy gauge cable from battery (-) to the fender apron.

T

Hemikiller said:
Looks like you have aftermarket battery cables, which means the factory battery to chassis ground is no longer present. These cars did not use the head to firewall ground strap. The factory negative cable had a strap that attached to the fender apron by the lower fastener (of the no longer present) voltage regulator. Add a heavy gauge cable from battery (-) to the fender apron.

Yeah right now the

Hemikiller said:
Looks like you have aftermarket battery cables, which means the factory battery to chassis ground is no longer present. These cars did not use the head to firewall ground strap. The factory negative cable had a strap that attached to the fender apron by the lower fastener (of the no longer present) voltage regulator. Add a heavy gauge cable from battery (-) to the fender apron.

sca5234 · Aug 19, 2024

sca5234 said:
Yeah I was showing someone what the before looked like when I first bought the car. it was overwhelming. Currently there is a ground going from the battery to the engine block. Do I need to change that to the

T

Yeah right now the

Currently the negative

Hemikiller said:
Looks like you have aftermarket battery cables, which means the factory battery to chassis ground is no longer present. These cars did not use the head to firewall ground strap. The factory negative cable had a strap that attached to the fender apron by the lower fastener (of the no longer present) voltage regulator. Add a heavy gauge cable from battery (-) to the fender apron.

Currently the negative is hooked directly to the engine block, included the picture. Should I have that attached to the fender apron instead?

72mokk1 · Aug 19, 2024

Do what Mac said and add a cable from the negative terminal to the apron or core support. Leave the cable on the block.

Hemikiller · Aug 19, 2024

sca5234 said:
Currently the negative is hooked directly to the engine block, included the picture. Should I have that attached to the fender apron instead?

You need to add a cable from the battery (-) terminal to the fender apron. Unless there is another engine to body ground strap hiding somewhere we can't see, you have no ground connection from the battery to the chassis. Engine, trans and radiator are all rubber mounted.

giantpune · Aug 19, 2024

If you're gonna buy a new battery cable anyways, you can buy a reproduction one that runs from the battery to the fender apron to the block. I'm running this set.

It matched the stock ones I pulled off very closely. Anything past that is gonna be you cobbling something together just like the "electrician" did before you.

https://www.cjponyparts.com/cj-clas...-air-conditioning-351ho-351-1972-1973/p/BC14/

Spike Morelli · Aug 19, 2024

Each person has their own ideas as to what they do to their car. I come from the K.I.S.S. school of automotive mechanics. I like everything simple, functional. It appears that the previous owner's ideas were to change the factory cooling fan /shroud, with electric fans and relays. Don't know why, not my Beeswax, but if you could go back in time and buy a brand new Mustang right off the lot, I'm sure you'd, we'ed, be suprised how well it ran and how everything works.

sca5234 · Aug 19, 2024

Spike Morelli said:
Each person has their own ideas as to what they do to their car. I come from the K.I.S.S. school of automotive mechanics. I like everything simple, functional. It appears that the previous owner's ideas were to change the factory cooling fan /shroud, with electric fans and relays. Don't know why, not my Beeswax, but if you could go back in time and buy a brand new Mustang right off the lot, I'm sure you'd, we'ed, be suprised how well it ran and how everything works.

Yes previous owner didn't abide by that mantra

quite the headache he has left me to resolve.

71 Mach shut down

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