55.2-59 Electrical

[2bo.c10]

Hi Everyone

I recently chased down one electrical issue on my 1958 Apache (finally got my brake and tail lights working) and I'm not sure if me messing with things is related to it - but now when I turn the key to kill the ignition, it doesnt turn it off. Any ideas of why that could be? What does that sound like?

Thanks!

[dsraven]

clarify "when I turn the key to kill the ignition, it doesn't turn it off". it stays running like normal and would keep running for days unless you stall it? it idles fast normally but now it stays running after the key is turned off but not running smoothly when this happens, more like running like a diesel or "run on" so it pings and runs rough etc? (this can be because of a fast idle with no idle stop solenoid to close the throttle plates when the key is off. a hot engine can draw enough air/fuel through the partially open throttle to keep the engine running in a "dieseling" style scenario where hot spots in the cylinders act like glow plugs and actually ignite the air fuel mixture). some other explanation?
clarify what you have for engine, ignition system (points or electronic), voltage (12 volts I assume), ignition switch type (old style on the dash or newer style in a swapped steering column), starter actuator type (old "step on the starter pedal", retro fitted push button start on the dash, old style ignition switch with "start" position, newer style ignition switch in a retrofitted steering column from a newer vehicle), alternator or generator etc
ensure there is a good dedicated ground to the frame, cab and engine
test ign switch operation
test for voltage at the distributor/coil with key on engine not running, key on and engine running and then key off when engine wants to stay running
test alternator next (could be back feeding power but usually the battery also dies overnight because the diodes in the alt allow the battery to be drained)
anyway, more info required
what was wrong with the tail lights, could possibly be a ground issue that affects the ignition system also?

[1project2many]

In addition to the above questions, please advise as to how you are currently stopping the engine.

[dsraven]

yeah, good point. you don't wanna end up doing a clutch or a diff or something because you shock load the driveline to stop the engine.

[2bo.c10]

Again! Thanks for the detailed reply - See answers in bold

Originally Posted by dsraven

clarify "when I turn the key to kill the ignition, it doesn't turn it off". it stays running like normal and would keep running for days unless you stall it?stays running like normal it did work at first until I started messing with the brake lights. There is a harness under the dash around connected to the headlight switch but I dont believe it was connected to the ignition - I will have to confirm though it idles fast normally but now it stays running after the key is turned off but not running smoothly when this happens, more like running like a diesel or "run on" so it pings and runs rough etc? (this can be because of a fast idle with no idle stop solenoid to close the throttle plates when the key is off. a hot engine can draw enough air/fuel through the partially open throttle to keep the engine running in a "dieseling" style scenario where hot spots in the cylinders act like glow plugs and actually ignite the air fuel mixture). some other explanation?
clarify what you have for engine235 Straight 6, ignition systemPoints (points or electronic), voltage12 Volt and has an alternator (12 volts I assume), ignition switch typeOld style under the dash (old style on the dash or newer style in a swapped steering column), starter actuator typeStep on starter pedal (old "step on the starter pedal", retro fitted push button start on the dash, old style ignition switch with "start" positionOne two positions for my key in the ignition, newer style ignition switch in a retrofitted steering column from a newer vehicle), alternator or generatoralternator etc
ensure there is a good dedicated ground to the frameframe is grounded well, cab Cab I believe is grounded well (will have to check but I believe it is)and engineEngine is grounded
test ign switch operationWill need to Youtube how to do this
test for voltage at the distributor/coil with key on engine not runningI can do this with my power probe but i believe the key does prevent the truck from starting if its not in the correct position, key on and engine running and then key off when engine wants to stay runningThis is exactly what happens
test alternator next (could be back feeding power but usually the battery also dies overnight because the diodes in the alt allow the battery to be drained)Battery is holding a charge - recently battery was low so I put it on the tickle charger and it fired right up after about 30 min
anyway, more info required
what was wrong with the tail lights, could possibly be a ground issue that affects the ignition system also?Not 100% sure but I still have a slight issue. When the turn signals are in a turn position (right or left) it causes them to act differently. When the turn signal switch is in neutral position, brake/tail lights work as they should

[2bo.c10]

to stop the engine, I am choking the carb

Originally Posted by 1project2many

In addition to the above questions, please advise as to how you are currently stopping the engine.

[dsraven]

sounds like the rear lights have a ground issue.
do you have a volt meter?or a test light? install that on the coil + terminal and see what happens when you turn the key off, engine stopped. then try it again with engine running.if it has power with engine running but key off, disconnect the power wire on the alternator and try it again. if that fixes it then you may have an alternator problem.

[dsraven]

run a test lead from frame ground to the lights and see if they work properly after that. no ground at the light will mean the power will go through the light bulb element and then through the ground but since there is no ground available it will go through the other element of the bulb and travel though the entire system until it finds a ground somewhere.you will likely find it changes if you turn the headlights on.

[1project2many]

sounds like the rear lights have a ground issue.
do you have a volt meter?or a test light? install that on the coil + terminal and see what happens when you turn the key off, engine stopped. then try it again with engine running.if it has power with engine running but key off, disconnect the power wire on the alternator and try it again. if that fixes it then you may have an alternator problem.

^^^ Very good set of test steps.

Additional questions:
Does your truck use a factory fuse panel with old glass fuses? You may have inadvertently moved a fuse or you may have the wrong length fuse which is bridging another circuit.

Did you connect any wires from light switch to another circuit under the dash looking for a power supply? Those wires by be unexpectedly powering the ignition. Can you tell if the intensity of the lights changes when the key is switched from on to off?

Did you accidently bump wiring at the ignition switch? You may have caused adjacent terminals to make contact when they should be separate. Locate problem visually and move wires.

[Dyslexic Dog]

Being an electrician, my thoughts from reading is that you are supplying constant power to the coil from the light switch. Check your wiring connections on the terminals. Somewhere, your coil is staying hot.

[DransportGarage]

Originally Posted by Dyslexic Dog

Being an electrician, my thoughts from reading is that you are supplying constant power to the coil from the light switch. Check your wiring connections on the terminals. Somewhere, your coil is staying hot.

Yup. The coil used to have "ignition" power (on only when key is on). Now it has "battery" power (on all the time), like for your headlights. Your mission, if you decide to accept it, is to find out what you changed. Start with any changes to the back of the ignition switch, then look for any wiring change that crossed "ignition" power with "battery" power. That would cause ignition power to BE battery power.

Here's another thing to try: With the engine running, key off, try unplugging your "fix" for the brake and tail lights. If the engine stops, try another fix for the brake and tail lights. (Hint: It's probably the ground for the light fix.)

[mr48chev]

I'd agree that if it shut off before somewhere there is a connection for full time power to the ignition from something you connected when you hooked the lights up.

One question, was the alternator on the truck previously and did it shut off when the alternator was on it before you hooked up the lights? That I ask because if you have the exciter wired to the ignition switch without either a diode or an idiot light in the circuit the feedback from the alternator will keep power to the coil.

Otherwise go back to where you hooked into power for the lights and check there to see that you don't have that wire or terminal making contact with the ign wire or terminal.