View Full Version : Ignition switch question
rychi1
07-31-2018, 10:53 PM
I have the Ron Francis wiring harness and have everything wired up for my key. Car starts and runs fine, however when I want to shut the car off I can turn the key and pull it out and it will still run. To get the engine shut down I have to turn the key back to the left, past the slot I can pull it out.
I went back through the instructions and I think I have everything in the right spot on the ignition switch.
Anyone have thoughts as to what I have incorrect.
JimLev
08-01-2018, 11:01 AM
I'd have to guess either the switch is wired wrong, the wires are labeled wrong, or the switch is bad.
I'm sure you probably already checked the wiring to the switch, maybe ohm the wires from the switch to the location they are suppose to go to according to the RF wiring diagram. Old school SBC with a coil? Check that wire, should be no power to it when the key is off.
If all is good, then it's the switch.
rychi1
08-01-2018, 11:58 AM
It is an SBC with an HEI distributor. A little more on what I have done, the distributor gets the Power from the orange EFI/coil wire (per instructions from FFR). The ignition switch I think is wired correctly but I will go back and take everything off and put it back on to make sure.
Do you have your electric radiator fan wired through a relay or is it powered from the ignition switch? If the latter you may be getting some electrons moving backwards as the fan motor acts like a generator. In this case the run-on may only last a short time as the fan spools down. This won't happen if the fan is powered through a relay even if the relay coil is connected to the ignition switch.
rychi1
08-02-2018, 07:37 AM
The fan runs through the relay.
JimLev
08-02-2018, 08:40 AM
Does your orange/EFI coil wire still have power when you turn the key off?
rychi1
08-03-2018, 11:40 AM
How exactly do I check that? How would the engine run if there was no power to the distributor?
JimLev
08-04-2018, 09:13 AM
The orange/EFI wire should only have power on it when the key is in run or start.
Put your volt meter + lead (or test light) on the orange wire on the HEI/dist. and the meter (test light) negative lead on the engine head or the block, not a painted surface.
With the key in the acc or off position you should not have power on the orange wire.
With the key in run or start you'll have 12 volts on the orange wire.
There have been cases of the switches being wired wrong internally. Remove the switch and test the function of each key position with an ohm meter.
Svtfreak
08-04-2018, 02:04 PM
Make sure your fan relay is wired right also. Unplug the fan and try it. See what happens. Does your fan run 100% of the time?
rychi1
09-05-2018, 08:13 PM
I tested the ignition switch with multimeter and everything seems to be working or not working when it is supposed to. I am working on connecting all of the wiring back up so I will test the other suggestions as I go.
rychi1
09-11-2018, 09:41 PM
Here is the feedback I have right now. Tested the orange coil wire, it has 12 v when keyed on and 0 when keyed off. Tried unplugging the fan, and still the same thing happens: starts, runs, and only cuts off when I turn to acc power.
rychi1
09-12-2018, 03:52 PM
Would it be useful to try to run the engine with the Alternator unplugged? Could I possibly have my alternator wired incorrectly?
Matt K.
09-12-2018, 05:44 PM
I don't know what kind of alternator set-up you have. But the alternator field circuit could be back-feeding voltage thru the ignition switch on certain installations. You might need to install a diode at the ignition switch.
OnlyAndy
09-12-2018, 06:05 PM
Just a comment from a Non Pro... I rewired my 40' Ford a few years ago with new everything. I think it was Auto Wire brand and had the same universal ignition switch they all have. Everything worked fine, car is seldom driven but this past spring I was going to a car event and it would not start. Figured the neutral start switch needed adjustment because it had come out of adjustment previously. Nope, all good, no start. Never had a problem with starter, maybe it went bad just sitting still. Took out bench tested, works fine. Back in still No start. Battery was new so last place to look was the place I never figured would go bad. Ignition switch. Took it out bench tested, worked fine EXCEPT the start position,,, ZERO. New switch, no more problem. But that defective switch even at 3-4 years old had on been used a couple dozen times. Don't assume the switch is ok just because its new.
JimLev
09-12-2018, 08:35 PM
Disconnecting the alt is worth a shot, make sure you disconnect all wires from it.
Somehow your HEI distributor is getting power when the key is turned off.
rychi1
09-13-2018, 08:46 AM
Ok my testing continued last night as follows: I tested the ignition wire at the switch; started the car, and then pulled the ignition wire, it cuts off. I then unhooked the wires from the accessory switch and key turns off engine as it should. So does this mean that I need a new switch, or that the alternator is backfeeding into the ignition switch and I need a diode as suggested above.
rychi1
09-13-2018, 09:23 AM
For what its worth, here is how my alternator is wired, with the green going to the accessory post on the ignition switch and the red going to the battery wire on the starter.
93151
Ok my testing continued last night as follows: I tested the ignition wire at the switch; started the car, and then pulled the ignition wire, it cuts off. I then unhooked the wires from the accessory switch and key turns off engine as it should. So does this mean that I need a new switch, or that the alternator is backfeeding into the ignition switch and I need a diode as suggested above.
Have you tried a one wire configuration for the alternator?
JimLev
09-13-2018, 01:34 PM
If it's a one wire alt you only need to connect the battery + wire to it.
What is the model and p/n of your alt?
rychi1
09-13-2018, 03:30 PM
Its a Tuff Stuff alternator (tff-7127) and I could hook it up as one wire but from what I have read the one wire set up is not the ideal choice.
Matt K.
09-13-2018, 05:21 PM
Try putting a diode in the green wire. They're dirt cheap, but it's tough to find a Radio Shack anymore. The band on the end of the diode should be facing away from the alternator.
JimLev
09-13-2018, 10:56 PM
Its a Tuff Stuff alternator (tff-7127) and I could hook it up as one wire but from what I have read the one wire set up is not the ideal choice.
This one....https://www.summitracing.com/parts/tff-7127
What's not ideal about a 1 wire alt?
Running it as a 1 wire is cheaper and quicker than adding a diode.
Give it a try to see if it fixes the problem and read the voltage before and after, should be the same.
rychi1
09-14-2018, 08:02 AM
So in response to the diode suggestion and some research, American Autowire already makes a solution for this: https://www.summitracing.com/parts/aww-500541 According to them "This kit is designed to prevent altenator feed-back to the ignition circuit" so I am going to plug this in and see if it works, if not I will look at converting to the 1 wire.
On the question about 1 wire, I have completely no knowledge base on this topic so when I came to the part in the manual about cutting up the wiring for a 1 wire alternator I looked into that and did a lot of online research. Several different sources made reference to the article below.
http://www.madelectrical.com/electricaltech/onewire-threewire.shtml
JimLev
09-14-2018, 07:59 PM
Might as well try the diode from Summit, plug and play.
That article is 16 years old, not sure all of it is relevant to today's electronics and better car wiring.
Anyways, it was an interesting read.