Key off but engine keeps running?

[rlux4]

Greg, what is a master relay on other cars must be the dual relay on ours. It's the relay that gets control signal from the ignition switch and the AFM, so I guess it could be considered the master.
Ron

[So Cal Mark]

has a stereo or amp been added? I'd first disconnect the alternator and see if that cuts power. Next would be to check the wiring connections at the starter. Recently someone posted about their cables at the starter coming loose, making contact and causing some odd troubles

[wengr]

Greg, what is a master relay on other cars must be the dual relay on ours. It's the relay that gets control signal from the ignition switch and the AFM, so I guess it could be considered the master.
Ron

Thanks Ron, is this the relay commonly reffered to on diagrams as the " fuel injection relay set"? Found under the glove box?

[wengr]

has a stereo or amp been added? I'd first disconnect the alternator and see if that cuts power. Next would be to check the wiring connections at the starter. Recently someone posted about their cables at the starter coming loose, making contact and causing some odd troubles

Mark, there are no new additions or changes to the electrical system that coincide with the start of the problem. I'll do the checks and report.

[rlux4]

Yes, it is under the glove box. Up on the black tray in front of the ECU, along with other relays.
It isn't a problem with your dual relay though. It doesn't have anything to do with the spark. It gets input when the key is turned on, then sends that 12V to the fuel pump when the flap in the AFM opens, which happens when you are cranking the engine or when the engine is running. In other words, if you had a problem with the fuel pump not running, it would be something you'd have to look at.
Ron

[So Cal Mark]

so the car used to shut off, then one day it just keeps running?

[wengr]

so the car used to shut off, then one day it just keeps running?

Yep, car was in daily use without issue, and then one day I removed the key and it did not shut off. It's not a result of any mods, as none were made. Thanks Ron for the info on the dual relay - saves me some time.

[rlux4]

This is getting weird!
When you disconnected the main connector downline from the ignition switch, that should have stopped power going to the coil. So, I'm stretching here, but have you looked inside the connector side that goes away from the switch? It sounds like something that would happen if it were melted and the red (or brown) wire has come into contact with the pink wire. Same thing as hot wiring a car.
Ron

[wengr]

Minor update. I have been applying the brake while letting the clutch out in first in order to stall the car. Last night as I depressed the brake pedal(ignition switch off and key out) the car shut off and all lights went out. As if the moving brake pedal contacted and shifted something under the dash, and fixed it. Tried it a few times since and it's now working correctly. I need to spend some more time under there and find what is wrong, and Ron, I'll be paying special attention to the wires you suggest. thanks Greg

[So Cal Mark]

sounds like some bare wires are making contact

[punes]

THIS HAPPENED TO ME, and it drove me nuts. Also some times I'd get in my 79 Spider and the dash lights would be lit up like the ignition was turned on...the answer is THE HAZARD switch.
If you slightly semi depress the switch or wiggle it, it will solve your problem.
As a test, without the key in the ignition I could light up my dash waring lights, by fiddeling with the hazard switch.

Once I replace the switch I never had the problem again....it took me 2 years to locate the issue.

Try it, the next time your car doesnt shut off semi press the hazard without actually activating the hazards and let me know.

Frank
79 Fiat Spider

[spider2081]

I am not familiar with the wiring for an 83. I am thinking the thing that can cause your problem is to have voltage all the time to the "Run" circuit side of the ignition switch. If you unplug the switch and the voltage is still there (car runs) then some place there is a short. Somewhere in the car, the battery wire ("hot all the time") circuit is shorted to the "run circuit". In my 81 there are two areas I can think of that this could happen.
1. In the area of the car where the battery wire connect to the starter and then the smaller wire continues to the alternator.
2. There is a brown wire that feeds the fuel pump dual relay that comes directly from the battery.
I would inspect these areas looking for a melted connector or wire insulation.
I would unplug the dual fuel pump relay
Hope this is some help

[spider2081]

Sorry I didn't notice Franks reply. His is very logical and I would try that first.

[azygoustoyou]

I think the problem only lies with the fact the car just isn't done with it's ride yet! LOL
Hopefully you figure it out. There's nothing more frustrating than not knowing why.

[bwilson27]

I'm certainly no expert, or even anything beyond a shadetree mechanic, but I'd bet anything that your constant 12v positive wire is somehow touching your accessory wire somewhere by your ignition switch.