The Stovebolt Site Forums The Shop Area The Electrical Bay 1957 3100 Ignition question

First off, a very basic question. When the ignition key is on, shouldn't there be power to the coil? Engine turns over nicely with the foot starter pedal, but immediately dies when the pedal is released. Checked power to the coil with the key on. Nothing. Dark green wire from the coil to the switch. continuity is there. At the switch, there are two dark green wires sharing the same connector/terminal. My wiring diagram does not show where the second dark green wire goes. (My diagram also shows a starter solenoid and not the mechanical starter switch.) I feel like I am missing something very obvious. Thanks as always!

Yes. Turning the key closes the "Run" circuit just like a modern car. Stomping the floor button only operates the starter. It's possible to turn the starter with the key "Off" and not start the car.

Run a test wire from the switch to the coil and see if it works.

You can hotwire the truck with a wire from the battery (+) to a toggle switch and a wire from the (+) side of the coil to the same toggle switch. Flip the switch and press the starter and see if truck starts and runs. If so, you'll know that your ignition switch is bad or that the wire from the switch to the coil is bad, or that the switch isn't getting power from the battery.

Agree and understand. So the current/12v comes through the dark green wire. So either the switch is not getting current (the fuel gauge registers when the key is on) or the switch is faulty? Or maybe the 12v must come from another contact? Hmmm.. Thanks!

Did you test to see if you have 12v at the ignition switch?

'57 with a stomp starter. The stomp switch has a terminal on the side that is wired directly to coil +. That provides 12volts directly to the coil when the stomp occurs. Once you let off the stomp (and assuming they key is on) 12volts from the ignition switch passes through a "ballast resistor" (usually mounted on the engine side of the firewall and on to coil +.

With the key on and the engine not running you should see the following at coil +.
12 volts if the points are open.
Somewhere around 8 volts if the points are closed.

By the way, your engine is capable of starting with the key off, but should die as soon as you get off the stomper.

Is your ignition switch a 2 position or 3 position (off-on-start)? If the latter, maybe you have the switch to resistor to coil wire on the "start" terminal of the switch.
The attached pic is from a 55.2 service manual (should be very similar) showing the ignition switch terminals.
The violet wire from the start terminal goes to the coil side of the resistor and the starter solenoid. That would only be from the start terminal of the stomp switch to the coil side of the resistor to bypass it with a stomp starter, but if your ignition switch is wired incorrectly, you wouldn't have 12V to the resistor and then to the coil unless the switch is in "start" position, which is usually spring return.

Take your test light & check for current at the resister. You should have current on both ends with the key on. If only on one side of the resister then the resister is open. If on both sides check for voltage at the pink wire on the ign. switch. If it has no voltage the switch is bad.

George

Initial problem. Engine wants to start with the foot starter engaged but stops immediately upon release of the switch. With ignition switch on, no current to the coil.
Attached is a photo of my switch.
There is a red wire coming to the BAT connector. It is hot/12v.
When the key is off, none of the other terminals have current/connectivity to BAT
There are 5 pink wires attached to the ACC terminal. They are all hot, when the switch is on. One of these wires is connected to the resistor mounted on the upper left of the cockpit firewall. All 5 wires have factory style connectors.
The IGN-2 terminal has no connectivity when the switch is on or off. 2 green wires using a single connector were attached here. One of the greens went to the coil.
The START terminal has no connectivity when the switch is on or off. A purple/violet wire was connected here. (Maybe to the headlight switch or...?)

Does this imply that my ignition switch is faulty? Or wires are incorrectly attached?

With that in mind, every parts retailer I could find shows a switch with only 2 ACC terminals and an IGN-1 instead of a START. Does a 5 terminal ACC type switch still exist?

Quick note. On the left side of the ACC terminal block is stamped IGN-1. I didn't see it for the dust

It is a 2 position switch. On-Off

Reverse the 2 small wires at the starter.

Follow the pink wire to the resistor. Is it 12v when the key is on?

If no, you need to fix the wire between the ignition switch and the resistor.

If yes, make sure the points in the distributor are open. Slide a piece of paper between the points to make sure.

Then check the voltage on the other end of the resistor. It should be 12 volts. If it is not, go to Step A (below).

Remove the paper and rotate the engine enough to make sure the points are closed. Check the voltage on the "other" end of the resistor again. It should be around 8 volts.

If it is 12 volts, the wire between the resistor and coil+ is open

If it is less than 6 volts some other electrical load must be connected to the resistor to coil+ wiring.

If you get here, let me know and I'll think about it more.

Step A.
If it is zero volts remove the wire that runs from the resistor to the points at the resistor. If the resistor still reads zero volts the resistor is bad (open).

If it is much less than 12 volts, something is providing a grounded load between the the resistor and the points. Check for additional wiring attached along the resistor to coil wire.

If you get here, let me know and I'll think about it more.

Bill, thanks for the detail reply.
I believe some of the issue must be the switch. Yesterday I had continuity from BAT to ACC with the switch on. Today, nothing. The '57 switch seems a bit unique as to find a match to mine, I can only find used. I have order a switch that reportedly will work. I will get back to you when it arrives. Thanks for your help and your patience! George

You could use a switch for your '57 that has a "start" position and just not wire anything to start, while still using your stomp starter. All the "usual suspects" carry that switch. And, you could put the proper wires on the IGN1 (run) and ACC pins on the switch so the radio (if you have one) can be used without the coil on.

George says he has a two position switch.... He shows the V8 switch I think. A 4 position switch. It's probably wired wrong as others have noted and George has guessed.
Would like to know what switch part number, from what vendor, is on it's way.

Click 1
Click 2

George,
If you bought the V8 switch, Test switch on bench so you can see it's operation first hand. Use continuity/buzzer sound on multimeter to test. Or if no meter, attach a 9V dc household battery to "BAT" terminal and use an ice pick tester....

1. Find the terminal(s) that is ON when ignition switch is in ON position, which is the last CW position before the spring loaded/spring return position.
2. Run a wire from that ON terminal to one side of the ballast resistor.
3. Run a wire from other side of ballast resistor to the coil positive.
4. Run a wire from the side terminal, of the switch on top of the starter, to coil positive. That makes two wires on coil positive terminal.
5. Determine during bench test what ignition switch position turns ACC terminal on/hot and when it is off. ACC position is full CCW position.
Wire all other components to either" Bat" terminal or "ON" terminal or "ACC" terminal. Depending on desired function and looking at wiring diagram. If you find that ACC is on/hot when switch is in "ON" position AND in "ACC" position, then you can wire to either. If "ACC" terminal is only hot in ACC position then use it as desired. Nothing is wired to any ignition terminal that is only hot at spring loaded position. (full CW position)
This will all be moot and unnecessary if you ordered the foot start switch (Click 2 above, $22)

Don't get too hung up on wire colors, they may have been changed.

To directly answer your past questions.
1. When the ignition key is on, shouldn't there be power to the coil?.YES
2. The START terminal has no connectivity when the switch is on or off. A purple/violet wire was connected here. (Maybe to the headlight switch or...?) The VIO wire is for a solenoid equipped starter. It can be labeled "start" or "sol". You do not use that terminal.
3. You're switch is missing the IGN 2 terminal. Broken off. Center hole. If I see what I think I see.
4. What you need is the "foot start" switch I linked above. Click 2, $22. Test this switch to verify it's continuity/connectivity between terminals. Ref 5.
5. Back then, ACC was just a word(misworded). Juist an extra terminal to wire to. It was not isolated to keep the coil from getting voltage. There is no "ACC" position on an ON/Off switch. The foot start switch terminals were all on or all off.
6. Using a V8 switch is confusing. Not Kosher. Don't blame you a bit for questioning it all.


Associated Commentary for Reference:
There is a difficult/confusing aspect to this. The V8 ignition switch is called the V8 switch because the 55.2-59 trucks had V8 or 6 available. The 6 were stomp. The V8 were electromagnetic solenoid. GM used two different ignition switches. The available online wiring diagrams, I use, only shows truck wiring for 55.2 but is the same to 59. The car diagrams are somewhat useful. The truck diagram does not show the stomp wiring as George has said.,.just solenoid/V8 switch. So to explain the stomp wiring, I have just spelled it out above to describe what to do with a V8 switch and a stomp/6cyl truck. I could describe which ignition terminal is wired to what, but chose for George to check and understand the V8 switch and wire as described. Least confusing. Colors, and how wires are shown in the diagram, can confuse. The ballast resistor/bypass circuit is different. 6 cyl/stomp uses the side terminal method and the V8/solenoid uses the ignition switch or "R" terminal method. All the while using different draftsman for different years who make terrible diagram drawings and choose their own way on how to delineate switches and etc.. Using the old fashion curly line crossings. At the same time using dark green all over the place and BLACK! for positive AND negative wires/cables!!!!! This was a period that was very confusing to engineers and draftsman. "OMG! 12V! V8 motors! Solenoids! burning points! What shall we do?". Non standardized messy drawings and sorting out how they wanted to start a car and truck, which switch, solenoid or not, "R" terminal bypass and how it's wired. Don't get me "started". Too late.