1993 240 Bad Ignition Switch?

[122sPhil]

if you open up the area near the shifter there is a piece of plastic film that dispays the shifter position. near there is a wiper thing that will only allow contact in neutral or drive.

You can jump it for testing purposes but domt leave it like that or you may start it in gear and have a runaway car.

when you assemble the shifter mechaism it is really easy to break the plastic bits and that piece of film has to be arranged properly. could be someone was in there before you and didnt arrange thigns quite right.

the ignitipn switch is held by two screws to the back of the keylock, theis is not an isue with the keylock it will unplug. if you are starting it with a screwdriver you may be in there already. you cna check the keyswitch with a voltmeter , for proper continuity. If the switch is bad replace it.

when you energise the keyswitch to start, it is sending power to the starter motor solenoid, when the solenoid pulls in it makes the high amp contact to run the motor. if the solenoid pulls in but the starter womt turn Id; clena and inspect or replace the starter solenoid,

the starter has brushes you can check their length and clean the commutator.

I think the same starter will work throughout a wide range of models , newer ones were smaller.
on really old cars you coul disassemble the solenoid and flip the contacts over , I thin at some point it became a sealed up unit. starters seldom fail so Id just find another , clean it up at the bench check briushes, bearings or bushings , lube it a little where needed, and replace it.
you can connect a hot wire stright from battery to the solenoid to test that if you like, or check for power there with the key turned and verify voltage. Id use a test lamp to see it from the key. also check the ground from battery to body and to the starter, big thick wire,, clean it up. and clean the battery to body contact up too.

if you have power and ground at the starter and the starter solenoid has power starter should run. if it wont run, , bad starter. If your key when turned to start does not energise the solenoid the problem is in the car's wiring, I'd isolate the problem to a starter issue or an electrical issue by determining which of the two scenarios you have.

sometimes the starter can fail to shift even though solenoid is energised. an old trick is to turn the key and have a helper give the starter a knock ( mechanical shock) like gibe the starter a whack with a 2x4 or iron bar or similar. if it helps it proves your starter needs some lube or a new one. or the gear doiesnt; have feeplay, there needs to be some backlash between the starter gear and the ringgear. it needs to slide in and out of mesh.

you can flip the ring gear for fresh teeth but you need ot have the transmission or engine out, big job!

[122sPhil]

suppose you measure power at the relay and get 7 volts, it is possible the starter solenoid is energised and what you are measuring on your meter is basically a series voltage drop. unhook that wire and verify if it has 12 V or less.

If you only have 7 volts with the solenoid disconnected and out of the picture then the issue is with the cars wiring.
7 volts to where? to some random ground point that couled be a bad ground or 7 volts to the battery? you might also have a bad ground, maybe battery to body or battery to the motor or starter or whereever the ground wire terminates. clean the grounds and the big hot wires ( all the wires that connect to the battery and the battery terminals)
no point not cleaning them the car is old , this means it needs doing. no point going into some electrical troubleshooting saga without assuring that this is not simply a bad contact to one of those big hot wires.

if the car is indeed starting the only key switch contact to concern with is the start position wire, the rest of the key wiring is not related to your issue.

isolate the confusion to that one wire because all the multiple wires at the key may cause confusion if you let it.

if the key switch itself is faulty you can instead instal a start button but keep those (shifter park and neutral safety swtich) wires as part of your circuit. you can still use the key to actually turn on the ignition and fuel pumps etc.

i htink if the key swith failed, then the only mod necessary is that the starter motor becomes powered from a button rather than the key's start position. if its important to stay OEM you can find a keyswitch. If you are cheap and or broke, then maybe just use a button and instead of turning the key to the start position push the button.

if only that part of the keyswitch failed that could be a workaround and you can maybe leave all else alone.

do not use a toggle switch. I had someone try to start my car, they froze on the key and gave it throttle, good god !
it spun the starter so fast it blew up the small gear, bits of the gear went up around near the flywheel and bent up the TDC sensor and my flexplate. well in order to access the flexplate i would need to pull the engine or the transmission..

I ended up drilling a 1 inch access hole and by lying under the car with a lot of patience I managed to straighten up my bent up flexplate, enough that the car would run.

i also once replaced an engine and managed ot pu thte flex plate on but in the wrong bolt hole, yea dont do that ;;-) it ran at a maximum 700 RPM and I was so frustrated

I think it was the only time I ever had a car towed in to have a mechainic work on it. the mechaic I had was so experienced that he diagnosed what I had done wrong in about 30 seconds , over the phone, That was pretty amazing. he had that tranny in and out in 2 hours..