Was Starting - Now not cranking 3.2

[awave]

1985 3.2 - Ran into a no crank no start issue. It was starting fine, then it wouldn't crank.

I wiggled the wires behind the ignition switch to see if they were loose. The red lights turned off. Thought that was the problem. Firmly pushed everything back together. Car started the next few times.

The next day go to drive it, no crank red lights on. When I turn the key to start I don't hear anything except a faint click coming from one or two of the plugs above the fuses.

It starts right up by putting power directly to the starter from under the car.

Read it could be-
DME relay (but it doesn't crank, bad DME would still crank?)
Starter (but starter starts the car from when jumped from under)
Ignition switch - plugged in another one i had and turned without the key - no crank. (ordering new one anyway)

Any help appreciated!

[GH85Carrera]

Likely the ignition switch, or a bad connection of the yellow wire. Or a bad ground.

The electrical part of the ignition switch is a real pain to replace, but it a likely culprit.

Fisrt off, stop and clean every ground, from the battery terminals the the transmission strap. Remove the connections, clean them on all sides, and reassemble. Bad grounds are a common issue with any old car. Clean the positive side battery cable even if it looks perfect, remove it get the connections pristine, and tighten up.

The DME relay will never stop the starter from running, just the ignition from firing up.

[911obgyn]

When i clean grounds i put a little dielectric grease on them to keep corrosion at bay.
Check the plugs under the dash bulkhead an make sure the one with the yellow wire is seated properly.

[awave]

Just cleaned the battery connections. I did not undo the battery ground. I will do battery ground and transmission today. Baking soda with water is best?

The one light click I hear is behind the key hole and one in the multi purpose relay.

https://www.pelicanparts.com/More_Info/91161510902.htm?pn=911-615-109-02-OEM&gclid=CjwKCAjwj8eJBhA5EiwAg3z0mxwzplcuOiviyKxe8ghh 0FLUZTC2Sl63xM3iYTKFVS6u2dBFmA53bxoCGkwQAvD_BwE

[Big Dav]

Originally Posted by GH85Carrera

Likely the ignition switch, or a bad connection of the yellow wire. Or a bad ground.

Fisrt off, stop and clean every ground, from the battery terminals the the transmission strap. Remove the connections, clean them on all sides, and reassemble. Bad grounds are a common issue with any old car.

I'll second this!

I had the same intermittent no crank from my '87 Coupe about a year ago. I removed the yellow wire off the starter to check the signal from ignition switch with a test light...... all good but the terminal was very dirty and greasy so I cleaned it all up and put it back together. I cleaned the transmission ground while I was under there which was also pretty filthy and have had no problems since. You've gotta love a free and simple fix.

[awave]

9/7 update. Replaced the transmission to body ground.
Cleaned the battery to body ground.
Cleaned the starter connections - Yellow and two red wires.
Cleaned battery connections and have a fully Charged battery.
Yellow wire on starter isn't getting power.
It will start when we put power directly to the start from under the car.
Hear two clicks one behind the key ignition. One from the relays above the fuses.

Is there a relay or a fuse for the yellow wire from the ignition to engine?

What should I do next?

[Big Dav]

It sounds like you've narrowed it down to the ignition switch itself. The electrical bit of it can be replaced but it's a bit of a pain to get to under the dash.

[cabmandone]

Originally Posted by awave

9/7 update. Replaced the transmission to body ground.
Cleaned the battery to body ground.
Cleaned the starter connections - Yellow and two red wires.
Cleaned battery connections and have a fully Charged battery.
Yellow wire on starter isn't getting power.
It will start when we put power directly to the start from under the car.
Hear two clicks one behind the key ignition. One from the relays above the fuses.

Is there a relay or a fuse for the yellow wire from the ignition to engine?

What should I do next?

Ignition switch. Pretty common failure.

[awave]

We disconnected the ignition switch and plugged the new one into it. Turned the ignition switch using a screw driver. Still not getting a crank.

[cabmandone]

Check your voltage at the starter where the yellow wire connects. IIRC, that yellow wire goes straight from the key switch to the starter.

Also, check fuses. If you're not getting power to the yellow wire you could have a blown fuse. Have you verified power to the key switch?

[awave]

We don't get any voltage on the yellow wire at the starter.
We are getting power at the key ignition switch.

Which fuse should we check. None of them look blown.

[cabmandone]

Originally Posted by awave

We don't get any voltage on the yellow wire at the starter.
We are getting power at the key ignition switch.

Which fuse should we check. None of them look blown.

I was just going through my fuse panel and didn't see anything for Ign. I'll do some looking in manual but I think the yellow wire goes directly to the starter. I'd probably disconnect power and check continuity on the yellow wire from the ignition switch to the starter.

[cabmandone]

Just checked my Bentley manual (warning! not the absolute best) and didn't see anything between the key switch and the starter at the yellow wire. You might try checking continuity at the yellow wire.

Take a piece of wire, put a male spade connector on it, make it long enough to get up to the drivers seat from under the car, test continuity from the switch to the female end. If you've got continuity and no power, you've got an issue in the switch.

[mysocal911]

Originally Posted by awave

We don't get any voltage on the yellow wire at the starter.
We are getting power at the key ignition switch.

Some Porsche owners in the past had problems with the #50 wire (yellow) from the ignition switch and added a relay/solenoid in series with the wire.
So you'll need to follow the #50 wire and determine if that was done to your car and is related to your problem.

[GH85Carrera]

Please, when you find the solution, post what fixed your car for future searches. It will happen again to some other 911 owner. They will appreciate your struggles.

[awave]

Originally Posted by cabmando

Just checked my Bentley manual (warning! not the absolute best) and didn't see anything between the key switch and the starter at the yellow wire. You might try checking continuity at the yellow wire.

Take a piece of wire, put a male spade connector on it, make it long enough to get up to the drivers seat from under the car, test continuity from the switch to the female end. If you've got continuity and no power, you've got an issue in the switch.

Sorry I don't follow. Put a male connector so it plugs into the 50 on the ignition switch?

[awave]

For anyone who has done this on an 1985 911. Do I need to remove the air box to follow the yellow wire? Or is there an easier way? The 5 pin connector with the yellow 50 wire comes through here?

I will definitely post the solution once this is solved. Thanks in advance!

[Techno Duck]

Check continuity of the yellow wire (pin 50).

[john70t]

Originally Posted by awave

It starts right up by putting power directly to the starter from under the car.

Battery connections, to fuse box, ignition circuit, inputs such as DME/crank sensor.
Something before the starter.

Wiggle wires.

[snbush67]

It looks like the part that you plug the switch into came apart and now it’s taped up.

You can pop the cover off. The wires in there are very close, make sure they aren’t touching and that they are in the right spots. I’ll try to find you a picture. If they came out it is possible that they didn’t get put back correctly.