1975 124 Weld Done While Battery Connected Car Won't Start

[Flyboytha1]

Hello all i'm very sad and sick to my stomach , i had a rear driver side floor pan welded in and the welds nice but the welder forgot to disconnect the freak'n battery while welding, now my car won't start at all what should i start checking for first. There's some power to the car like the head lights work, i think it's the door open or key buzzer still buzz when the key is in, there's power is in the ignition, can't remember if there's 2 that are always live, but there a few that have power when the key is turned into the start position that then works and have been tested but there's a couple that don't have power when the key is in nor have power when in the start position.

I've been restoring this car for the last 6 months and have done all the work myself with the help of my wife here and there and have never taken it to a shop, i always feared this as i have so much time into it this freak'n happens on the first time I've let the car out my sight .

The weird thing to me is the lights in the dash don't work anymore like the brake on light and a few lights that would come on in the cluster gauge area, I've check the fuse box no fuses are blown, I bought a new coil, points and condensers that i will be installing today and hopefully that will be some of the issue, checked most of the fuse breakers that are capped under the dash nothing seems to be blown inside those i have found and open to check.

I have a feeling it's something minor hopefully cause some stuff still works but obviously somethings been fried when the weld was done with the battery connected.

Need help of what to check for.

[bradartigue]

You're going to have to do some tracing - I wouldn't start buying anything yet. Test the main power lead connections from the battery to the starter, then the alternator, ignition switch, etc. You may find it fried a couple of weak points - like the ignition switch - and left some of the more isolated or stronger areas alone.

[majicwrench]

So does it not crank or not run once cranking? IF it cranks, have you even checked for spark?? To test fuses you need a test light, you cannot just look at them to see if they are blown, often the connection fail not the fuse.
Get back to us with some basic info and we can likely point you in the right direction.

[DieselSpider]

With breaker points in a 75 there should not be any delicate electronic ECM to fry from electric welding. Sure that a connector or wire did not get burned from the heat or unplugged to get it out of harms way and not reconnected to its proper mate?

[Flyboytha1]

So does it not crank or not run once cranking? IF it cranks, have you even checked for spark?? To test fuses you need a test light, you cannot just look at them to see if they are blown, often the connection fail not the fuse.
Get back to us with some basic info and we can likely point you in the right direction.

Does not crank and start anymore when the key in the start position the engine just turns on and on but not starting, i used the test light to test the ignition switch but didn't use the test light on the fuses only reason i look to see if anything was blown cause a few weeks ago the gauges stopped working went to the fuse box sure thing popped fuse replace it everything starting working again.

I will test the fuses with the test light tomorrow didn't think of that.

[Flyboytha1]

You're going to have to do some tracing - I wouldn't start buying anything yet. Test the main power lead connections from the battery to the starter, then the alternator, ignition switch, etc. You may find it fried a couple of weak points - like the ignition switch - and left some of the more isolated or stronger areas alone.

Already bought new points coil and condenser's yesterday but haven't installed them yet, my next step is to see if there's any spark in the coil to the disturber i read some were that if the condenser's are no good then it won't start either way.

[Flyboytha1]

How can i test the ignition switch it self? Reason i ask cause i had just bout a 78' fiat for small miscellaneous parts door locks, trunk lock etc. but i did remove the ignition it self the other day, looks the same with the same amount of rear prongs on the end/back of it but obviously different wiring but not all the prongs was being use on the 78' switch like on my 75'. Just curious if the 78' ignition switch can be used on the 75'.

Thanks again guys!

[DieselSpider]

So does it not crank or not run once cranking? IF it cranks, have you even checked for spark?? To test fuses you need a test light, you cannot just look at them to see if they are blown, often the connection fail not the fuse.
Get back to us with some basic info and we can likely point you in the right direction.

Does not crank and start anymore when the key in the start position the engine just turns on and on but not starting, i used the test light to test the ignition switch but didn't use the test light on the fuses only reason i look to see if anything was blown cause a few weeks ago the gauges stopped working went to the fuse box sure thing popped fuse replace it everything starting working again.

I will test the fuses with the test light tomorrow didn't think of that.

Are you getting power at the main lug of the starter solenoid? I would start there to ensure that the main line from the battery is still intact at that point. Follow the route of the power from the battery to the starter to ensure it is 100% intact and not partially burned through only passing enough power to run a few dash lights. Was any creative wiring done running a second power feed to the dash leaving the main to just power the starter? My eye would be on any wires that could have been physically damaged from the heat where the welding was done which in my mind is the main harness running the length of the car on the left side.

It can be frustrating to have to play Dick Tracey and don't discount that it could just be a pulled or pinched wire from removing the seats or moving the harness out of harms way.

[spider2081]

I don't have a print for a 75 Spider. However in most of the Spiders battery power is fed to the ignition switch on 2 wires. One is black and one is brown. The brown wire feeds the portion of the ignition switch that engages the starter solenoid. Often it is the largest wire on the on the ignition switch. This wire physically originates at the alternators output post.
So as stated there should be power at the starter solenoid post that has the battery cable on it.
There should be power on the alternators output post with the ignition switch off.
There should be power on the big brown wire and the black wire on the ignition switch with the switch off.
There should be power on the red wire on the ignition switch with the switch in the start position.

I agree with previous post, I don't think welding with battery connected caused this problem.

Hope this helps

[Flyboytha1]

I don't have a print for a 75 Spider. However in most of the Spiders battery power is fed to the ignition switch on 2 wires. One is black and one is brown. The brown wire feeds the portion of the ignition switch that engages the starter solenoid. Often it is the largest wire on the on the ignition switch. This wire physically originates at the alternators output post.
So as stated there should be power at the starter solenoid post that has the battery cable on it.
There should be power on the alternators output post with the ignition switch off.
There should be power on the big brown wire and the black wire on the ignition switch with the switch off.
There should be power on the red wire on the ignition switch with the switch in the start position.

I agree with previous post, I don't think welding with battery connected caused this problem.

Hope this helps

I here you and will double check your suggests, but the problem with all this is i drove the car there with nothing inside but the drive seat install with just the 2 screw holding it in place center console was still install but nothing else to get in the way but to disconnect the battery and do the weld, I've always heard the battery should be disconnect when welding, and after i got the car home i searched more into welding with the battery connect and TIG welding is the worst which is how it was welded it.

Having the battery connected to me problem is massive current flow and the battery will allow it to flow through it. Battery not connected no current flow from the welder or induced voltage will go through the vehicles electrical system.

The guy may have disconnected the starter wire while he had the car in the air the starter is right there to do this but never installed it on the correct area but also i didn't look at the area close to were the weld was done there's a harness bundle there that as stated that could have gotten hot or melted, either way i will be playing Dick Trace and see what i can find today while the weather permits lol

[ga.spyder]

Nothing to add except that these guys that are trying to help you,are a few of the best we have to offer! Follow their lead and good luck.

[Flyboytha1]

Nothing to add except that these guys that are trying to help you,are a few of the best we have to offer! Follow their lead and good luck.

I'm listen to everyone and i know they have very good intention to point me in the right direction, but after doing all this work and the first time i let the car out of my hands and this happens it had me sick to my stomach

[majicwrench]

Stuff is gonna happen. Look at it as a good opportunity to get to know the wiring/ignition system better. If it failed now, likely it would have failed sooner or later anyway.

[spider2081]

I agree with majicwrench, Stuff happens. Years ago a customer was beside himself because he checked out his plane in the morning and everything worked then later in the day his radio would not function. A fellow tech told him "everything works until it breaks". That didn't make the customer happy but its true. Trouble shooting requires keeping an open mind, knowing how something should work, and taking logical steps to isolate the problem.
Regardless of the cause of your problem someone has to troubleshoot it to correct it. A great learning experience is available here that more than likely will be useful in the future.

[RoyBatty]

If i understand right, your starter is turning the engine over but the engine is failing to run?
Try running temporary jumper wire from the alternator output to the positive side of the coil. Then try to start the engine.
If this gets you running, you now know that the parts in the distributor and the coil are working. This let's you know you have a fault in the wiring from the ignition switch to the engine compartment. If it does not run, then you may have cooked a coil, condenser, or welded the contact breakers/ points together.