Car Runs Even When Switched Off Options

[silver six]

Here's a strange one: My 914-6 (3.2 liter from a 1984 911 (engine code 930/21))will continue to run even when I switch the ignition off and pull the key out. The idiot lights on the dash turn on and the guages are killed (the tach goes to zero eventhough the engine continues to run). I can kill the engine in this state, however, by stomping on the brakes. Pressing the brakes half-way do not kill the engine. I have to depress the brakes fully. Then the engine dies. Turning on the headlights will not kill the engine.

My first guess is that the alternator is running the engine even after juice from the battery is cut. And I further guess that the ignition switch is causing this. But I'm not sure.

I sure could use some advice.

Douglas

[Brad Roberts]

Typical 914/6 fashion.

The ignition switch is slowly becoming toast.

Not an easy task replacing it (unless somebody has replaced it in the past) Drilling out the rivets that hold the factory switch in is a chore.

B

[Dave_Darling]

Factory six or conversion?

If it's a conversion, the ignition switch is easier to replace...

Silly question--have you replaced any of the light bulbs (brake lights, for instance) lately? Or shortly before this problem started? Putting a dual-filament bulb into a socket intended for a single-filament bulb, or vice-versa, can have very strange effects.

Power can feed back through the light socket into one section of the ignition switch, and that can provide enough power to run the engine. It will on a four-cylinder car, at least!!

--DD

[Brad Roberts]

I cheated Dave.

I knew it was a factory 6 car with a 3.2 in it.

B

[silver six]

Thanks boys. Very helpful. Brad is right: it's a factory 6 with a 3.2. Dave, I can't think of any bulbs I replaced but I did install a new set of 8A fuses to replace the 16A and 25A fuses that were in the box before and should not have been (except for two 25A fuses as indicated in the owner's manual).

And, Brad, as for getting to the switch, well it turns out I rekeyed the whole car about two months ago and decided that since getting those stupid shear bolts out were so hard in the first place I just replaced them with normal bolts (I'm happy to discuss why I believe this does not create more of a security risk than the original shear bolts, if anyone is interested). So getting to the switch should be a 10 minute job.

Thanks again, Brad and Dave for your input.

Douglas

[campbellcj]

Shear bolts and just about any other device invented by mankind to try to deter theft are basically wastes of time these days. Any serious thief will just tow the car away in about 30 seconds...see ya... (IMG:style_emoticons/default/wavey.gif)

Of course, ignition/fuel kill switches and the like definitely will slow down the joyrider punk kids.

LoJack setups also do seem to have positive results, although I think they (used to) cost $500 or so, which is tough to swallow unless you're practically convinced ahead of time that your car will get stolen. A guy I work with did have his truck get stolen from his driveway one night. Cops recovered it within a few hours via the LoJack. Damage was minimal.