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Item Posts    Sort Order

'72 won't start

 
rckstr
New User
Posts: 5
Joined: 09/13
Posted: 09/04/13 05:10 PM

I've adopted a wreck. I'm aware of my limitations as a mechanic, but the brakes and steering a good, and I keep a fire extinguisher handy, so I feel the general public is safe. Here appear to be three cars of the 71-73 flavor pieced together with sheetmetal and bondo, so we'll call it '72. With the ignition switch 'on' I was only getting 4volts or less to ground 'tween ignition coil positive(MSD 8202) and ground. (By the way, the wiring harness is all cut up into pieces) My bright idea was a jumper from the hot side of the solenoid. Fired up and ran great!; I drove like that for 'bout 60miles. It was a bunch of fun! Now that it won't start again and I'm getting 12volts to ground from the MSD, I wonder: a) Did I fry the MSD? or b) Did I fry the ignitor (Pertronix Carb E D-57 2)?  

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waynep712222
User
Posts: 223
Joined: 04/13
Posted: 09/04/13 08:03 PM

so many things it could be..

and.. i have a question.. i am taking that when you installed the coil.. that you chopped the push on elbow end that is normally pushed onto the ford coil positive..

i have found several that still had the elbow push on connector shoved on the coil with a ring terminal just sitting on the stud..  yea.. like thats going to work right.. its not...

the second to the last page of this 132 page msd wiring manual is how you want to check the msd box..


http://www.msdignition.com/pdf/WireDiagrams/WDTN.PDF

and how are you shutting down the MSD or ignition.. pulling a jumper wire off???


pertronix.. tips and trouble shooting

http://www.pertronix.com/support/tips/


i might be able to help you with a lot of issues.. but do you have some pictures you can post.. .  this would help a LOT..


i can walk you thru testing why your ignition switch is not getting power to the ignition system.. if you own a digital volt meter... and perhaps a test light..  

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waynep712222
User
Posts: 223
Joined: 04/13
Posted: 09/04/13 08:57 PM

on the ignition switch... toss a set of jumper cables under the car... hook up the positive one thats near the front of the car to the positive battery...

with the other end laying on the pavement under the drivers door opening..  hook your digital volt meter lead to that..  the other lead.. hook to the yellow wire going into the ignition switch.. turn your key on... you should have almost no reading.. as you are looking at the resistance in the copper wire...  if you have more than 0.1 volts.. you have a bad connection somewhere in the harness between the starter solenoid and the ignition switch...

now.. turn off the key...    move the test lead under the dash to the red and light green wire where it comes out of the switch...   again turn on the ignition switch.. you should have the same reading as you had when you tested the yellow wire.. and thats less than 0.1 volts   thats 1/10 of a volt..  

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70bird
User
Posts: 86
Joined: 07/13
Posted: 09/04/13 11:38 PM

yes you likely fried the coil or pertronix. try a different coil. if no spark then pertronix is bad.  

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rckstr
New User
Posts: 5
Joined: 09/13
Posted: 09/05/13 03:10 PM

Thanx for the replies and especially for the links. You cats sound like very useful mammals, and I wanna bother you wih this somemore. My job has atacked me though and it may be this weekend before I get to play car again.....Till then.  

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70bird
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Posts: 86
Joined: 07/13
Posted: 09/06/13 12:02 AM

"useful mammals", lol. not according to my wife!

we'll be here  

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rckstr
New User
Posts: 5
Joined: 09/13
Posted: 09/09/13 06:33 PM

K, long story short; I burnt the ignitor. What got me to jumping things out is that my wiring harness is in pieces. While working on other things, I'm thinking I'd do well to cut away everything not necessary to start and run the car, and charge the battery...... Y'all ever tried such a thing? Remember I'm ignorant to auto electric, and what exists isn't much of a guide. My color code and wire count doesn't match any wiring diagram I've seen. I have an assortment of buttons and switches at my disposal though. If I take + from battery and use a maintained contact to the coil; a momentary contact for the starter solenoid and I've started the car haven't I? I've heard folks say don't worry about resistance, but is too much voltage maybe what killed my ignitor?.........Or does the ignition coil start with one voltage and run with another?........Keep in mind, the starter circuit is fine.It's visible enough to feel good about. And the battery charges, so I'm ignoring that for the moment.  

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waynep712222
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Posts: 223
Joined: 04/13
Posted: 09/09/13 07:32 PM

ok... lets slow down...

before going in with a axe and clippers to remove what might NOT be needed

did you find a proper wiring diagram for a 72???  they are available fairly easily online...

lets test what you already have....

identify the individual wires...  what service they perform....

you will want to take the wiring diagram you get to a copy shop .. and have them BLOW it up fairly large and paste it to your wall.. so you can follow it..

i know this is more complicated than just cutting and hacking .. but thats how the car got in that condition already... right..

the are only a few reasons to chop and hack out stuff...

its going to be a dedicated drag race car ONLY. trailered to and from the track...

or its going to end its life soon in a demo derby..

there are a few more reasons.. but we won't discuss them here..

invest in a bag of tie wraps... and a 4x4 sheet of peg board....

disconnect the engine harness.. and mount it.. noting where the corners and break outs are... on the peg board as you attach the harness kinda loosely to it... but with enough slack you can pull wires out and put new ones in...  if you make the ZIP tie connection on the back of the peg board.. it will be easier as you won't have all the tails sticking up at you...



i linked the MSD trouble shooting manual.. did you verify how to hook up the MSD with the pertronix ignitor..???? or what ever brand..  the slightly later duraspark distributors will trigger the MSD boxes directly.. its exactly what MSD uses in some of their distributors..

the pertronix if that is what you have.. LIKES 12 to 14 volts on the RED wire into it...

if you have an Msd box hooked to it.. and the coil..  you might smoke it again...

i don't recall which motor you have.. but you can buy a reman distributor at most parts stores..

pay the core charge so you can keep the original one... don't turn it in.. please..   you may regret it later...   you can also put points and condenser back in the point type distributor and it will also trigger the Msd box just fine...  

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waynep712222
User
Posts: 223
Joined: 04/13
Posted: 09/09/13 08:23 PM

by the way..  i have all three wiring diagrams so if you describe the colors you are testing.. i can look them up and describe them 71, 72, 73..

on all point type ignition fords...

the wire from the IGN1  on the ignition switch it becomes a resistance wire..  comes out and connects to the  wire that comes over from the I wire from the starter relay..


how this works.. when the key is in the run position.. the power flows from the ignition switch thru the resistance wire to the coil positive..    the reduced voltage also flows over to the I terminal on the starter relay.. but thats should be an OPEN connection inside the starter relay..

when you are cranking the engine... the relay disc is pulled up and across the 2 posts.. but .. it also connects to the I terminal.. this sends close to full battery voltage from the I terminal on the relay.. to the ignition coil + .  this bypasses the resistor in the wire near the ignition switch..

so.. while the key is in the on position.. there should be around 10 volts on the coil positive..

while cranking there should be closer to 12 volts on the coil positive..

but why am i describing this...

because i have had issues where the contact inside the relay.. stuck to the stud that if hooked up properly.. goes down to the starter motor..  if this happens.. the ignition circuit will be pulled low and the engine will not have any ignition power...

i have also had the big wires hooked up backwards...  and that contact on the inside of the I terminal stick to the BAT + terminal..  preventing the engine from shutting off...

your ignition circuit is like this... you have a different switch


Mustang Starting System5  

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waynep712222
User
Posts: 223
Joined: 04/13
Posted: 09/09/13 08:25 PM

take some decent pictures of what you are working with..

upload them to photobucket..   paste at least one of the links here..

i will see if i can help...  

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rckstr
New User
Posts: 5
Joined: 09/13
Posted: 09/11/13 04:44 PM

Oh! We're havin' fun now. Gimme a minute to take some of this apart; only so many hours in the day ya know.

We will eventually find something burnt though. When I first got the car, the instrument cluster was melted together and the car would die everytime you turned any of the lights on. It looks like the previous owner started cutting on things chasing shorts maybe? I'm past that and on to the task at hand. Be back shortly.  

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70bird
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Posts: 86
Joined: 07/13
Posted: 09/12/13 02:04 AM

too much voltage did not kill your ignitor unless it somehow got more than 12v from the regulator, this is unlikely

if you leave the key on, on a pertronix with the engine off for a few hours you can kill it.

try different coil like i said and if needed a points set up, no fancy junk.

remove ign wire from coil

jusp coil npos to batrery pos

jupm solenoid.

you will have spark.

buy new harnesses from drake.  

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rckstr
New User
Posts: 5
Joined: 09/13
Posted: 09/16/13 02:40 PM

When I grow up I wanna be just like you guys....You've gotten me rollin'......Mr.70Bird may be right. My home is occassionally occupied by heatherns who like to play around an old car as much as I do. I can easily imagine the ignition staying on too long. And, Wayne draws the koolest pictures. My dumbass was looking at the starting solenoid and thinking S and I were like A1 and A2 on a conventional relay. I saw the contacts on my wiring diagram but was guessing the keyswitch must be fancier than it looked. In the end I've strung together enough to start and run with correct voltages in the right places. I really want a new wiring harness for fear the old one will catch fire, but this setup will keep me mobile while I do all this body work I'm looking at...........Once again; thanx guys...I really appreaciate it.  

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