1947 Chrysler Electrical

[Caddy60]

I have been working on trying to get spark on my Chrylser, I Have had many responses from members and followed up but so far no spark.  One of the members had mentioned it could be the Ignition switch.  I have no knowledge how to test if the switch is actually turning on the ignition.  There is 6 Volts showing at the back of the switch & when I do turn the key I can push the starter button and the engine turns over.  Is it possible that the switch allows the engine to turn over but does not give power to the ignition system??  I notice when I turn on the key there is zero movement on the ammeter.  If I pull the light switch the ammeter  moves to the discharge side, even when the starter is turning the engine over there is no movement of the ammeter.

 

Bruce Watson

[TerryB]

Hello again Bruce.  Just wanted to tell you my 1951 Pontiac with push button start would turn the engine over with the key in the OFF position when the button was pushed.  Turning the key to ON connects battery voltage to the coil so the engine can start.  Perhaps it’s time to have a pro look at your problem.  Good luck!

Edited April 20, 2022 by TerryB (see edit history)

[TerryB]

I will also add you need the wiring schematic for your car to aid you in your pursuit of this problem.  A schematic printed in color is even more helpful.

[TerryB]

This might help you

 

[Joe Cocuzza]

Check to see if you have voltage on the NEG(-) side of the coil. That voltage comes from the ignition switch and the transmission relay mounted on the DS inner fender in the diagram. You can run a wire directly from the NEG side of the battery (if the car is still POS ground) to the NEG(-) side of the coil and then see if you get spark. But don't leave it connected too long.

Also, when you turn the key ON and OFF you should hear a "click" sound coming from that relay. 

[Oldtech]

Ok. a bit of leading "by the hand" on this, Can you confirm to us using a test lamp or meter that you have voltage on the neg side of the coil, as Joe said.

If none, then suspect switch.

If there is voltage there your problem is likely in the distributor.  A picture of it with the cap off would be a great help. 

[plymouthcranbrook]

A fairly well known issue is the wires in the distributor going to the points can have a break in it and cause either intermittent spark or no spark at all(not always visible). Comes from movement of the wire over time. 

[Rusty_OToole]

A simple 6 volt test light will tell you everything you need to know in a few minutes, such as whether the coil is getting power, whether the points are working etc. You can make one out of a bulb and a couple of test leads with alligator clips,

[Ben Bruce aka First Born]

Would not a 12V work? Just dimmer?

 

  Ben

[Larry Schramm]

1 hour ago, Ben Bruce aka First Born said:

Would not a 12V work? Just dimmer?

 

  Ben

 

yes

[Caddy60]

I thank all those members that have given me different avenues to rsolve the poblem of NO spark.

I walk away from the problem and keep trying different ideas.

I connected a wire from the ignition switch to the coil, turned the key on and my meter show 6 volts at the coil  but no ignition.  would this indicate that the switch may be at fault?

[TerryB]

40 minutes ago, Caddy60 said:

I thank all those members that have given me different avenues to rsolve the poblem of NO spark.

I walk away from the problem and keep trying different ideas.

I connected a wire from the ignition switch to the coil, turned the key on and my meter show 6 volts at the coil  but no ignition.  would this indicate that the switch may be at fault?

It’s the job of the ignition key to turn on a source of battery voltage that goes to the coil. Once the coil gets voltage it’s up to the points and condenser to make a spark at the spark plugs by interrupting the coil flow in the coil.  Each time the points open, the coil will generate a momentary high voltage output. The position of the rotor inside the distributor when this high voltage is created determines which spark plug gets the high voltage to make a spark.  That’s ignition basics 101 for today.

 

So it sounds like you now have a jumper wire going to the battery side of the coil.  With this wire added do you measure continuous 6v on the battery terminal of the coil?  What do you measure on the distributor (points) terminal of the coil?  When the points are open this terminal too should measure 6v and when the points are closed this terminal should be at 0 volts (ground). If you don’t get zero volts when the points are closed then there could be a problem with the points such as dirt or corrosion (which is very common) on the contacts or there may be a broken wire inside the distributor.  If you can take and post pictures of your coil connections and your meter it would be helpful.

Good luck!

 

[Bloo]

^^This is the way. You need to have 6 volts at one coil terminal with the ignition switch on, probably the negative one because I believe the Chrysler is positive ground. You need to have the voltage going on and off at the other coil terminal as the engine turns over. This is measured from a coil terminal to a good engine or chassis ground in both cases.

 

You could use a meter I guess, but the digital ones sometimes don't play nice around ignition systems. I would prefer a test light. A cheapo one or a homemade one would be fine.

 

If there is no power at the coil at all with the ignition switch on, and the battery is not dead, the ignition switch or the wiring is suspect.

 

If there is power at one terminal and none at the other when the engine turns over, either the coil is really bad (burned out), or there is a problem in the distributor. To find out, shut the key off, disconnect the small wire from the distributor to the coil terminal, and turn the key back on. You should now have 6 volts at both terminals. If not, and you still have power at one terminal but not the other, get a new coil. If you have power at both terminals, the trouble was in the distributor. Either the points are not opening, or the wire is shorted to ground somehow on it's way to the points. Investigate and find out!

 

If there is 6 volts on both small terminals of the coil (distributor is hooked up as normal), and the one connected to the distributor does NOT go on and off while cranking the engine, there is a problem in the distributor. It is one of 4 things. 1) The points are not ever closing (gap too wide). 2) There is some schmutz on the points preventing continuity when they are closed. Clean them with a points file or any tiny file if you have one. One or two drags ought to do it. If not, try dragging a piece of paper soaked in brake cleaner between the points. Sandpaper is not advised because it can leave behind crud that shortens point life. 3) The wire going to the points is broken either outside or inside the distributor. Inside the distributor special wire is usually used that can take flexing over and over without breaking. It could be broken inside the insulation. It should not stretch. 4) If the distributor has vacuum advance, and if that vacuum advance functions by moving the plate the points are bolted to, there needs to be a ground wire from the plate to the points case. It is more special wire meant to bend almost forever without breaking, and will probably be bare. I am almost certain the Chrysler is built this way. You should be able to see the bare wire in there with the distributor cap off. Make sure it is there and not broken.

 

If you have power on one coil terminal, and the power on the second terminal goes on and off while you crank, as it should normally, and you still have no spark or extremely weak spark, get a new condenser and try again. If you still have no spark with a new condenser, get a new coil.

 

Good luck. Let us know what you find.

 

Edited May 6, 2022 by Bloo (see edit history)

[TerryB]

Yes, the test light on the points side is a great way to observe the open closed points.  Analog meters with the moving pointer were good too.  Digital meters can be slow to show the change and if they have auto ranging turned on that alone will drive you crazy!

Harbor Freight has test lights for cheap!

 

[Rusty_OToole]

If you are getting power to the coil but no spark next thing to check is the points. As they open and close they act as a switch, turning the electricity off and on. A 6V test light will tell you if this is happening. Every time the points open the coil should make a spark. So check points, if they are working right check for spark. If the coil is making sparks next step is to have the distributor distribute them to the right spark plugs. Diagnosis is simple if you follow it up step by step.