Ingition Switch Help. Do heavy keys make a difference?

[320iBodhisattva]

Hey Guys (and I'm sure a couple gals. I'm new to the forum and just getting started on my new addiction. I've owned my 1981 320i for the last 6 years and use it as a daily commuter. So far she has treated me very well, I haven't really needed to do anything to it since I purchased it, except change the oil and a new set of tires. I've put 40k miles on it, well worth the $1,500. I purchased it over other "newer" models as I figured if anything goes wrong, it would be a good learning experience about car mechanics and since there are no electronics the fixes would be more DIY favorable. I've grown to love the little thing, but this month seems to be the time the universe says time to start learning...So I've found myself up late at night reading post and looking at endless threads, diagnosing my latest car troubles. This month I was forced into learning the 320i basics almost something new each week, replaced the fuel pump, fuel filter, distributor cap and rotor, head gasket valve cover gasket, timing issues, and new plugs. This week its THE IGNITION SWITCH. So I think.. This is where I need some help.

I left the keys in the ignition over night last night and today the car wouldn't start. Is a heavy key chain enough to break an ignition switch? The engine doesn't turn over, just nothing. The electric seems to work when the key is in position #2 (dash lights, annoying door buzzer, fan blower etc.) then when I go to start it, the tachometer pins itself and nothing, no sounds. I cleaned the battery terminals and connections coming from the battery, that didn't seem todo anything. Then I got the idea to try a different key. I put my spare key in the ignition gave it a good luck giggle and vroom it started. It wouldn't start with the key that is on the heavy key-chain but does with the lone spare key...? Is this the IGNITION SWITCH? Another symptom I noticed now as well, is when I get the car above 2,500rpm the thermostat starts going crazy swinging back and forth in both directions as the car gets to 3-3,500rpm it almost seems like its going to die, I did push it to 4,000rpm and it died. It still starts with the alone-key and the special giggle but not the standard key (which seems like its a hair smaller or more worn than the spare) still has the problems when getting above 2,500RPM. What do you think?

Is the DIY ignition switch (with key) an easy beginner project? Is this where I should start?

(FYI: I have been using the heavy key chain for the last six years, is there a specific spot in the ignition column that this type of stress presents itself?)

Thanks for your help.

[Tom D]

the key lock and ignition switch are two different pieces and the key is only 'unlocking' the cylinder so that it can rotate the switch. therefore if the key is turning then that's not your problem.

the switch is two pieces, a stationary housing held in place by the steering column and a internal rotating section that is driven by the end of the lock cylinder with the key. inside the switch is various contacts, 2 floating plates and 2 or maybe 4 springs that hold pressure on the plates to assure good contact with the various different points. the problem occurs when the plates lose contact, but the switch can be rebuilt.

remove the lower steering shaft cover and look for ignition switch at the base of the cylinder lock. you'll find a small grub screw, it will probably have some yellow paint on it, remove the screw and then remove the switch. pry open the 2 halves of the switch being careful of the internal floating plates and springs. clean out the old grease, the contacts, the plates and give the springs a bit of a stretch. using dielectric grease lube everything up and put the switch back together.

[Tom D]

here are the two half of the switch. the first photo is the rotating piece with the floating plates, there are two springs under each of them. when the key is turned it rotates the plates and they make various connections depending on key placement. the second photo is the end cap and attached to a wire loom.

IMG_1856.jpg

[320iBodhisattva]

Thanks Tom.

I'm getting on it tomorrow and will let you know how it goes.

[amarino]

And here is what the switch looks like assembled but broken outer housing.
IMG_20131118_175353.jpg IMG_20131118_175403.jpg

[320iBodhisattva]

Alright, so. the car didn't start at all again today, regardless of the key I used. I could tell that it was probably something electrical do to the straining I could feel and see when it run at higher RPMs yesterday. I decided todo some testing with the only equipment I had on hand, a pair of jumper cables and a screw driver. I connected them at different points to the battery and followed where I could get a spark from. I was getting a spark at the starter when I turned the key, so I figured it wasn't the ignition switch contacts. Also, after trying to start the car several times I saw some faint smoke coming from some where (like something was frying). I then grounded the engine to the neg (-) terminal of the battery with the jumper cables and Vroom it started. It appears to be the ground isn't grounding the engine anymore. And this is causing the no-start ignition as well as the electrical strain on (thermostat, alternator or what ever other electrical parts) at the higher RPMs when running.

I'm totally new at this, does this make sense? Also where would the Original faulty ground be located (1981, 320i)?

Here is a picture of the work around I came up with to get me on the road. I strapped two 12in battery ground straps together, bolted one end to the engine and one to the car. (I guess I can't post pics yet cuz I'm to new.) When I can I'll update with the picture).

Seems to work.

[amarino]

Check this thread. May need to install a "photobucket workaround" plugin for your browser to see the pics: https://www.bimmerforums.com/forum/s...0-Ground-Strap