How to Fix that Sticky Ignition

Porsche_monkey · 10-17-2002, 09:04 AM

I have read a lot of posts about older 'sticky' ignitions, they work up to the 'run' position, but won't click over to the 'start' position.

I have disassembled my ignition (not easy) , I know why it happens and how to fix it. It is not for beginners, but if anyone wants to know how to do it reply to this post and I will answer in detail (with pictures!).

Tim Polzin · 10-17-2002, 09:56 AM

I've personally seen two types of ignition switch problems. One is electrical and is fixed simply by replacing the switch element.

The other is mechanical where the flat potmetal "drive" to the electrical switch cracks off. This second failure, in my case, resulted when I let someone drive my car. He immediately stalled the engine on take-off and I think tryed to force the key to restart.

PBH, did you repair the pot metal element? If so, I know what you went through as it is a real PITA to do.

Porsche_monkey · 10-17-2002, 10:01 AM

I completely dissasembled the pot-metal part including the steering lock. There is a thin metal washer that acts as a carrier for the ignition plunger. The washer wears out and the spring plunger jumps off the washer and into the detent that holds the ignition in the run position. Once the plunger is in run mode it won't click over into start mode. I had to braze the hole in the washer, grind it off and drill a new hole .075" dia.

Works fine now.

john walker's workshop · 10-17-2002, 10:44 AM

inside, there's a steel pin that slides along a pot metal ramp. the ramp gets a notch worn into it and won't allow the pin to slide past. that particular problem looks non-repairable to me, unless you can fill the notch with something that won't come off later.

Porsche_monkey · 10-17-2002, 10:50 AM

I ALLWAYS defer to John Walker, but on my ignition the washer allows the steel pin to step over the ramp, then a cam stops the washer from moving. The pin slides off the washer (after crossing the ramp) and then when the key is released from 'start' to 'run' mode the pin slips into the ramped area, which is the 'run' detent.

The key has to be reset to the '0' position to pick up the washer and get to 'start' mode again.

This is repairable.

I will post a picture shortly.

1980SC · 10-17-2002, 11:23 AM

I have also fixed my ignition switch this way. Luckily, all I had to do was disassemble and clean everything. I saw the wear on the metal washer, but my main problem was dirt keeping the hole from grabbing that pin. Put is back together, and has worked great ever since. I took pictures too, but where did they go ...?

Rob
1980SC

Porsche_monkey · 10-17-2002, 11:28 AM

Rob: How did you remove the dowel pin that holds the assembly together? I had to put my lock in a milling machine and use an end-mill to remove it. To re-assemble it I had to drill oversize and use a 3/32" roll pin.

john walker's workshop · 11:35 AM

to get the pin out, i drilled a tiny hole right next to it, with a jet drill, just deep enough to get a pointed tool in against the pin, and then worked the pin out with the sharp tip. the pin is very short, so 1/16" is enough. maybe there's a better way. i'll try the washer repair next time i get one out. hey, i see one on the bench. sounds like if the problem is just the washer, and not a notch in the pot metal, them it's fixable.

1980SC · 10-17-2002, 11:36 AM

I used a trick that John Walker told us about. I put the assembly in my vise, punched a mark adjacent to the pin, and drilled a small hole. Then I dug the pin out. Worked great! I just reused the original pin when I put it all back together.

david914 · 10-17-2002, 01:29 PM

I am having the same problem on my '82. I would love to see a pictorial! It sometimes takes several attempts to get the key to advance past the "run" to the "start" position. HELP!

bigchillcar · bigchillcar's Garage

PBH,
Pretty sure that my problem of late is electrical ('74 911). The 'on' position is fine, but the 'run', where you hear the fuel pump turn on, etc. is intermittent. I've figured out over the last 10 days or so if it doesn't that I reach behind the dash to the back of the ignition switch and jiggle around a moment or two and on it goes.

Wanna know the really weird part though? I can count on having to do this process in the morning, but never in the afternoon when I leave work. Any guesses? I'd love to see some pictures of what I'm soon going to be working with...as soon as I get the car back from the body shop today!!

Thanks,

Ryan

1974 911 2.7 CIS coupe w/sunroof

Porsche_monkey · 10-18-2002, 05:32 AM

Might be worth removing the switch and drilling a small hole to allow spraying some contact cleaner inside. Of course once you get that far it would seem to be reasonable to replace the electrical portion of the switch.

RoninLB · 10-18-2002, 05:32 AM

Ryan.. I changed the electrical part of the switch as preventive maintance at 120k miles..cheap insurance against future electrical insanity............Ron

Porsche_monkey · 10-18-2002, 05:37 AM

Where's the fun in that? Isn't being stranded somewhere part of the joy of motoring?