No spark has me stumped?
 

I have a ‘31 closed cab pickup. It stopped running and can’t get it to start. Cranks fine, fuel delivery seems ok, but there is no spark. Ammeter does not deflect when ignition turned on or when cranking. With ignition on I have 6 volts on both sides of the coil. When I place the high tension lead from the coil next to the block and manually open the points there is no spark. It’s a newer coil so I’m thinking it’s not that (but I guess it could be). Anyone have any ideas. Thanks.

Re: No spark has me stumped?
 

Have to inspect everything south of the coil. That includes the ignition switch, armored cable, and distributor (lower plate, wire, points and condenser).



Did it die and you couldn't restart it or was it sitting and then couldn't be started? If the former, my guess is bad condenser. If the latter, dirty points.



Another important question. Did you have voltage at the points when they are open?

Re: No spark has me stumped?
 

As mentioned, first thing is to check voltage at points. Should be 6v at open point arm and 0v when closed.
Place coil secondary wire 1/4" from a good ground. turn key on. manually open/close points. every time points are opened there should be a good spark.
My suspicion is either dirty point contacts or bad condenser. I just went thru 5 new condensers til I found a good. Even the 'new and improved' short-proof condensers are of poor quality.

Re: No spark has me stumped?
 

Ignition on - 6 v on the points arm, when points are closed both sides of the points should be 0 volts and about 1/2 to 1 amp discharge on the ammeter.


Sinice there is 6 volt on both sides of teh coil, primary most likely is good, but you could take one lead off of it and measure for about 1.5 ohms across teh terminal to confirm.


Since one side of the coil does not go to ground with the points closed, and your ammeter does not wiggle with points opening/closing - you have lost the ground provided to the coil via the points. Measure voltage at the points, or you can ohm with ignition off from the coil to ground and see if there is a short with the points closed.

Re: No spark has me stumped?
 

All the above ! Keep in mind that the ignition switch connects the downstream side of the coil to the points so a continuity check of the switch is in order.

Re: No spark has me stumped?
 

I believe Bratons has a how to check the ignition switch, it's very good!

Re: No spark has me stumped?
 

Ignition switch check ?
Simple
Voltmeter/continuity meter/ test light. Any will work.


If there is voltage at both coil terminals but not to the points. Then there is a problem somewhere in between,

Re: No spark has me stumped?
 

if truly stumped try hotwiring it to aid diagnosis ( I use croc clips on the wires)

Re: No spark has me stumped?
 

Ignition cable from key can go bad and ground out. Shake the cable,test and see if outside of cable is hot. I just found when cranking over a Tudor I just bought,the manifold vaccum line got hot.
Wire behind dash was causing it.

Also check ignition wire at the distributor where it goes into it.

Re: No spark has me stumped?
 

The ignition wire inside the armored cable to the distributor shorted to ground on my car. It was the original wire and the insulation had disintegrated. Took me a while to track that down.

Re: No spark has me stumped?
 

Yep, and as Wick also said. Its kinda common on these old monsters.

Re: No spark has me stumped?
 

Was told today of a Rock-Ford-A's member that had a stall, got it going and home and the start and stall started as they searched for the trouble . After much testing and head scratching the team found an interment short in the ignition cable which allowed for a weak or no spark. Good catch guys.

Re: No spark has me stumped?
 

Do the simple things first. Check the wire in the lower plate.

Re: No spark has me stumped?
 

Yes, the flag terminal is very close to the housing and the top plate. Examine it to see if it might be touching.

Re: No spark has me stumped?
 

Thanks everyone. I’ll keep you updated.

Re: No spark has me stumped?
 

I would replace any other original wiring that remains in the car - it will eventually short. not long after the ignition wire shorted, the pigtail in the brake light shorted, causing a 10 amp discharge every time I stepped on the brake pedal.

Re: No spark has me stumped?
 

Yep... good advice. I never seem to do that! I'll learn...LOL

Re: No spark has me stumped?
 

I’m chasing this same thing on my car right now...
Drove it about 5 miles last night, drove into the yard, let it idle for about 1 minute and it quickly shut off as I walked away and I knew it wasn’t good.
Came back and tried to start it and nothing.

Re: No spark has me stumped?
 

I'd like to add, the spark advance rod can ground out the outer cable. If you are missing the boot Goin into the junction box,it can ground on a terminal post. And lastly some of the modern points,the attachment plate can hit the inside edge of the distributor and ground.

Re: No spark has me stumped?
 

Well finally solved no spark issue. One of the previous owners soldered the wire from the ignition switch to the plate in the distributor(where the spring loaded connector makes contact). Apparently a blob of solder fell between the lower plate and distributor shorting out the circuit. Removed blob and now have spark.