Hey guys, lots of motors won't start, mine won't stop.

[rbogh901]

Well, that’s great but it’s not always what I have in mind. Let’s just say I got this car, (long story), and it’s new to me. Anyway, where I come from you turn off the key and then the engine stops. Not this one. It just keeps humming.

Well, that’s great but I was thinking it would be good to turn it off once in a while. So, when the time comes I ease it into 3rd, low idle, and gently put it out of its misery. Although it’s effective I was hoping for something a bit more, you know, elegant. Seeing as how I have a day job and don’t consider myself an expert in these matters I kinda need some hints.

This car will not be a long term keeper but needs to be functional if rough. Is there a red wire someone removed that needs to be attached to the ignition switch to make all this a little easier? When you turn the key to the “off” position shouldn’t spark be stopped? Can I wire a kill button on the handle bars like my MX bikes always had?


Thoughts?

[T77911S]

you might tell us the year.

do all the other electrics go out that normally come on with the key when you turn it off.

[john walker's workshop]

I can't remember what year the car was, but I remember one like that, where someone put a single terminal bulb in the double terminal brake light socket and until the brake pedal was released, the car wouldn't shut off. Through some weird wiring scenario, the crossed terminals fed back and kept the ignition on.

[lite75]

keep driving!!!

[Scott S]

Are you running an MSD ignition?

This happened to my 914-6 conversion after installing an MSD 6AL. It's been so long, I cant remember how I fixed it - but it was a pretty quick fix. If I recall, this issue may have even been addressed in the instructions.

[jlex]

Haven't seen that happen on a Porsche, but it's not uncommon on a VW bug if a wire to the coil is crossed with another wire. Could be the ignition switch is worn out, but if it checks out okay, I'd be looking at your power feed wire to the coil being powered up by another line.

[T77911S]

Originally Posted by john walker's workshop

I can't remember what year the car was, but I remember one like that, where someone put a single terminal bulb in the double terminal brake light socket and until the brake pedal was released, the car wouldn't shut off. Through some weird wiring scenario, the crossed terminals fed back and kept the ignition on.

i wired the brake pedal to the horn on a guys car here at work, actually the work truck he drove, perhaps someone has played a joke on him

[bigel]

Definitely do not close the garage door...

[rbogh901]

Originally Posted by T77911S

you might tell us the year.

do all the other electrics go out that normally come on with the key when you turn it off.

Funny you would ask as it is a 77 and your tag suggests you might be a 77 guy yourself.

So, 1977 911S it is.

The PO had the same problem and, at some point, through a 3rd party, relayed that his preferred technique was to use 1st gear. I assume it didn't occur to him that higher gears might be less dramatic.

In any case, there's more. He had one of those cut off switches with a big red plastic key on a long large gauge wire dangling next to the ignition and spliced with a generous electrical tape wrap to the negative ground at the battery. To start the car the cut off is switched to the on position and the fuel pump starts. Then you twist the ignition to fire the starter and turn the engine over. Once started the key cannot stop the motor.

I had an RM-250 when I was 15 and the kill button on that thing killed the spark. I assume that is what stops a 911 motor too. Is that correct?

[Mike80911]

Had the same problem with my car a while back. This thread might help.
Car will not shut off

[rbogh901]

Originally Posted by john walker's workshop

I can't remember what year the car was, but I remember one like that, where someone put a single terminal bulb in the double terminal brake light socket and until the brake pedal was released, the car wouldn't shut off. Through some weird wiring scenario, the crossed terminals fed back and kept the ignition on.

That's funny. I would check my bulbs but this mongrel doesn't even have brake lights at this point. Just raggedy wires where the housing should be... I'll make sure none of them are shorting, release the brake pedal and turn off the key to see what happens, WTF.

But, I don't think that's gonna do it. Thanks though.

[wildthing]

Dieseling?

Just guessing. This hasn't happened on my PCar.

[Vereeken]

Originally Posted by T77911S

i wired the brake pedal to the horn on a guys car here at work, actually the work truck he drove, perhaps someone has played a joke on him

That never gets old.

Must do that again sometime.

[Puma]

This happened to me once. Previous owner had a heavy key ring. The weight of the ring caused the ignition key to sit at an angle and wear the contact points prematurely. I drilled the ignition out and replaced it. Problem solved.

[T77911S]

i would think there would be a battery drain with the car off.
with it off, listen to see if you hear the CD unit on. just curious.

that's kind of what I was thinking, maybe ignition switch bad or miss wired but if there has been a lot of jury rigging in the wiring I would look for the CD to be wired hot all the time.

I don't have a 77 diagram so not sure of this.
power from the ign sw also goes to the fuse block in the engine bay to power the WUR and AAR.
if they hot wired the Wur on that would keep the CD unit on

[rbogh901]

Originally Posted by lite75

keep driving!!!

Good advice. I intend to!

[rbogh901]

Originally Posted by Mike80911

Had the same problem with my car a while back. This thread might help.
Car will not shut off

Thanks Mike. This didn't come up under my search but it is helpful and I learned something. I didn't know about a delayed ignition relay. My impression is that it would not be needed as my car is PMO carb converted, (by a reputed builder, documented). Therefore it might be unnecessary although I don't know that I have one nor have I researched where to look.

[rbogh901]

I unwired the battery cut off and will consider a better solution for that. Dangling from the HVAC vent wasn't really my idea of the kind of "rough" car I had in mind.

Interestingly, connecting the negative lead back to the battery causes the fuel pump to run. I pulled the fuse and it stopped. Put the fuse back and it pumps. I pulled the fuel pump relay and same thing so apparently their contributions to the circuit are preserved. Otherwise the fuel pump is always on. There is also a relay click in the frunk when the pump is disabled and the negative terminal at the battery is connected so something else is always on. Is there 2nd fuel pump relay up there?

Makes me think ignition switch might be more of a suspect than the brake light wiring.

[rbogh901]

Originally Posted by Puma

This happened to me once. Previous owner had a heavy key ring. The weight of the ring caused the ignition key to sit at an angle and wear the contact points prematurely. I drilled the ignition out and replaced it. Problem solved.

I wouldn't put it past him, the PO that is. It's not clear how that would happen since the tumbler is a separate component from the switch. I can see wearing out the keys in the tumbler but maybe it could affect the switch too. Apparently it solved your problem so it is a consideration.

If I pull the wiring plug from the back of the switch it should cut all power I assume. If it does then the always on problem must be in the switch. If not then it must be elsewhere in the wiring.

[ASD]

run forrest run!