Hmm...intermittent turn-key-nothing-happens issue

[Effervescent]

95 M3 with 116k.

From time to time recently, I turn the ignition key and nothing happens. No click, no turning over. The usual dashboard lights are on.

Yesterday it happened for 5-10 mins. I walked away and came back 20 mins later and it started right up.

Could this be a battery starting to go bad? A key-chip issue? Something else?

Has happened about 10 times now. But usually for just a few tries. Twice for about 5 minutes.

HELP!

-Eff

[bmwdirtracer]

You'll likely need a new ignition switch. (The electrical side) You can confirm this by pulling the lower steering cover when issue is occuring, and using a test light on the black and yellow wire when turning key to "Start" position. If test light doesn't illuminate, replace switch. (Easy)

[EuroPartConnect]

You'll likely need a new ignition switch. (The electrical side) You can confirm this by pulling the lower steering cover when issue is occuring, and using a test light on the black and yellow wire when turning key to "Start" position. If test light doesn't illuminate, replace switch. (Easy)

+1, also have seen were the clips were broke on the ignition switch so the key was just turning and not making contact with the ignition switch. either way i would start there as that is more than likely your problem

[Effervescent]

You'll likely need a new ignition switch. (The electrical side) You can confirm this by pulling the lower steering cover when issue is occuring, and using a test light on the black and yellow wire when turning key to "Start" position. If test light doesn't illuminate, replace switch. (Easy)

Great stuff.

A couple quick questions:
1) Got an image of an BMW ignition switch?
2) Got a part #?
3) Approximate cost?

-Eff

http://www.partsgeek.com/gbproducts/...ek+Google+Base

$77 sounds right? This part number sound right?

-Eff

[bmwdirtracer]

That looks right; the part number shown is not a BMW number -but that means nothing; the picture is correct.

But really, you need to test that wire before throwing parts; this is only the most likely failure point, and is a BAD diagnosis unless the testing is done. You MUST find out where the problem is - start by testing the black and yellow wire at the switch, then go try the same test at the black and yellow wire at the starter, if the first one goes hot. If both go hot, test voltage drop at the starter main power, and at all feeds to that point. And then you'll need to check engine ground, dme ground, etc -- What I'm saying is don't throw the parts 'til you know which to throw. IT COULD BE that your starter can't take the heat - a problem I had with my race car yesterday.....

EDIT: But no one beat me; and I drove it home, too.

[pbonsalb]

Possible loose battery ground. Check in the trunk at battery and frame.

Possible bad starter solenoid. Replace starter.

[Tangent]

My ignition switch went bad on me a couple of weeks ago. By removing the switch and connecting the wiring while it wasn't mounted I was able to get more reliable starts. This led me to believe that the switch was making poor/intermittent contact and just dismounting it was enough to make it work better. $80 for a new switch and express shipping from Pelican Parts later I got the new one installed and haven't had a problem since. At least on the E46 it's easy enough to get to that there's no reason to not remove the switch and check it's function before throwing money at a new one.

[bmwdirtracer]

You won't even need to remove it, just check for hot at the black and yellow's terminal when your symptom is manifesting.

[Effervescent]

FELLAS! It was just a dying battery!

Despite driving it around all that weekend (with the annoying starting issue) it was complete dead 5 days later when I tried to start it.

$99 at Pep Boys. Works fine now.

I remember this being an issue I had once on a Yamaha sportsbike as well.

Thanks though, I opened up under the steering column and found a wire with split insulation...which is why I think I have to reset my airbag every couple of months.

2 for 1!

-Eff