The Ford Barn

Cider Mill · 06-03-2012, 08:42 PM

OK, I thought I knew what I was doing with the Model ignition. My 29 tudor ranOK, but had terrible wiring through out. I replaced the generator to terminal box and car ran OK for several weeks. today I decided to rebuild the gas gauge and replace the dash to terminal box harness. How hard can it be - only 3 wires. Now I have no spark at points, 6 volts on one side of the coil and none on the other with key on - but when I turn key off, I get 6 volts to both sides of coil, but still none at points. I am confused - what did I screw up? distributor plates and wire look OK. I also re-timed, changed plugs and plug wires, condensor and coil to distributor wire while I was at it.

I have yellow wire from starter to passenger side terminal box terminal, gen cut out to driver side terminal. Red wire from pos coil to ignition switch, black wire from neg coil to passenger side terminal box and ammeter wire to each of the terminal box terminals. I did not change the coil, ignition cable or anything in the dirtibutor.

What happened? Any suggestions appreciated!

Gary WA · 06-03-2012, 10:01 PM

Ignition switch shorting to the dash panel? repo or popout? if just on off switch the two screws on the switch may be touching metal??

Mike V. Florida · 06-03-2012, 10:46 PM

"...but when I turn key off, I get 6 volts to both sides of coil, but still none at points." That too would be correct if you have a non pop out switch since the voltage would come from the battery through the coil and end up not connected to anything when the switch is off.

"Now I have no spark at points, 6 volts on one side of the coil and none on the other with key on -..." With the points closed that would be correct now the wire not connected to anything in the switch now goes through the switch and is connected to ground. So as the points are grounded and the coil terminal going to the points through the switch would also be grounded.

Place a piece of paper between the contacts of the switch and see if you now have voltage at the points

Look at the copy of the wiring diagram and see that you have everything right.

Yellow wire from starter to terminal box, terminal box to amp meter.

Yellow and black wire from amp meter to the other post in the terminal box, terminal box to generator cutout.

Black wire on the same terminal as the yellow and black to the coil post.

Red wire from the other coil post loop through the terminal box and to the switch.

Wiring Diagram,

Stinch · 06-04-2012, 09:33 AM

I was with Cider Mill with this problem yesterday so I'll throw out some observations. The instrument panel is detached from the tank so no short possible there (for now anyway). The switch is a repro with two screws, one going to the distributor. The wire goes into an old piece of conduit which I recall was screwed into the distributor base. A screwdriver was placed across the switch terminals and there was a small spark when the screwdriver made contact but nothing to create smoke (as a short). However, still no sparking at points. Not sure if I trust that switch; I recommend removing the switch and test the points using just the two terminal wires.

Hadn't thought of checking voltage at points with the contacts insulated/open. Good one to check.

Rich

Cider Mill · 06-04-2012, 09:39 AM

I did notice a very small sparking inside the key switch when turning off/on. It is odd to me to have power at both terminals of the coil with key off, power to both terminal box posts, but not any at points - open or closed. I ordered a new key switch and ignition cable. We will see what that does for us once I receive them later this week.

jrelliott · 06-04-2012, 10:03 AM

Sponsored Links (Register now to hide all advertisements)

With the wiring correct on a Model A, there will be voltage on both sides of a coil when the ignition switch is in the "OFF" position. THe ignition switch is in series with the coil to the points. Believe your problem is a open from the ignition switch to the points. You can check this with an ohm meter. BTW disconnect the battery before making this test or can fry the meter.

Cider Mill · 09-24-2012, 11:15 AM

Just a belated update: turns out there was a short in the armoured ignition cable from key switch to distributor. When I replaced the ignition cable and key switch with repops, I got a bad repop key switch. I was finally able to fix the new key switch and everything worked as it should. She started right up. Thanks for the suggestions and be wary of repop ignition parts!

Steve Wastler · 09-24-2012, 11:57 AM

Be wary of ALL repop parts, and only use when absolutely necassary. There is only a VERY SELECT FEW I buy repop from when needed.

06-03-2012, 08:42 PM	#1
Cider Mill Senior Member Join Date: Oct 2010 Location: Shelton, CT Posts: 339	thought I knew what I was doing??? OK, I thought I knew what I was doing with the Model ignition. My 29 tudor ranOK, but had terrible wiring through out. I replaced the generator to terminal box and car ran OK for several weeks. today I decided to rebuild the gas gauge and replace the dash to terminal box harness. How hard can it be - only 3 wires. Now I have no spark at points, 6 volts on one side of the coil and none on the other with key on - but when I turn key off, I get 6 volts to both sides of coil, but still none at points. I am confused - what did I screw up? distributor plates and wire look OK. I also re-timed, changed plugs and plug wires, condensor and coil to distributor wire while I was at it. I have yellow wire from starter to passenger side terminal box terminal, gen cut out to driver side terminal. Red wire from pos coil to ignition switch, black wire from neg coil to passenger side terminal box and ammeter wire to each of the terminal box terminals. I did not change the coil, ignition cable or anything in the dirtibutor. What happened? Any suggestions appreciated!

06-03-2012, 10:01 PM	#2
Gary WA Senior Member Join Date: May 2010 Location: Clinton,WA/Whidbey Island Posts: 4,101	Re: thought I knew what I was doing??? Ignition switch shorting to the dash panel? repo or popout? if just on off switch the two screws on the switch may be touching metal?? __________________ www.whidbeymodelaclub.com

06-03-2012, 10:46 PM	#3
Mike V. Florida Senior Member Join Date: May 2010 Location: South Florida Posts: 14,054	Re: thought I knew what I was doing??? "...but when I turn key off, I get 6 volts to both sides of coil, but still none at points." That too would be correct if you have a non pop out switch since the voltage would come from the battery through the coil and end up not connected to anything when the switch is off. "Now I have no spark at points, 6 volts on one side of the coil and none on the other with key on -..." With the points closed that would be correct now the wire not connected to anything in the switch now goes through the switch and is connected to ground. So as the points are grounded and the coil terminal going to the points through the switch would also be grounded. Place a piece of paper between the contacts of the switch and see if you now have voltage at the points Look at the copy of the wiring diagram and see that you have everything right. Yellow wire from starter to terminal box, terminal box to amp meter. Yellow and black wire from amp meter to the other post in the terminal box, terminal box to generator cutout. Black wire on the same terminal as the yellow and black to the coil post. Red wire from the other coil post loop through the terminal box and to the switch. Wiring Diagram, __________________ What's right about America is that although we have a mess of problems, we have great capacity - intellect and resources - to do some thing about them. - Henry Ford II

06-04-2012, 09:33 AM	#4
Stinch Senior Member Join Date: May 2010 Location: Connecticut Posts: 220	Re: thought I knew what I was doing??? I was with Cider Mill with this problem yesterday so I'll throw out some observations. The instrument panel is detached from the tank so no short possible there (for now anyway). The switch is a repro with two screws, one going to the distributor. The wire goes into an old piece of conduit which I recall was screwed into the distributor base. A screwdriver was placed across the switch terminals and there was a small spark when the screwdriver made contact but nothing to create smoke (as a short). However, still no sparking at points. Not sure if I trust that switch; I recommend removing the switch and test the points using just the two terminal wires. Hadn't thought of checking voltage at points with the contacts insulated/open. Good one to check. Rich __________________ E30 68-B Cabriolet

06-04-2012, 09:39 AM	#5
Cider Mill Senior Member Join Date: Oct 2010 Location: Shelton, CT Posts: 339	Re: thought I knew what I was doing??? I did notice a very small sparking inside the key switch when turning off/on. It is odd to me to have power at both terminals of the coil with key off, power to both terminal box posts, but not any at points - open or closed. I ordered a new key switch and ignition cable. We will see what that does for us once I receive them later this week.

06-04-2012, 10:03 AM	#6
jrelliott Senior Member Join Date: May 2010 Location: Pine, AZ Posts: 794	Re: thought I knew what I was doing??? Sponsored Links (Register now to hide all advertisements) With the wiring correct on a Model A, there will be voltage on both sides of a coil when the ignition switch is in the "OFF" position. THe ignition switch is in series with the coil to the points. Believe your problem is a open from the ignition switch to the points. You can check this with an ohm meter. BTW disconnect the battery before making this test or can fry the meter.

09-24-2012, 11:15 AM	#7
Cider Mill Senior Member Join Date: Oct 2010 Location: Shelton, CT Posts: 339	Re: thought I knew what I was doing??? Just a belated update: turns out there was a short in the armoured ignition cable from key switch to distributor. When I replaced the ignition cable and key switch with repops, I got a bad repop key switch. I was finally able to fix the new key switch and everything worked as it should. She started right up. Thanks for the suggestions and be wary of repop ignition parts!

09-24-2012, 11:57 AM	#8
Steve Wastler Senior Member Join Date: May 2010 Posts: 1,987	Re: thought I knew what I was doing??? Be wary of ALL repop parts, and only use when absolutely necassary. There is only a VERY SELECT FEW I buy repop from when needed.