1999 s320 starting problem sometimes
 

Yes my s320 maybe after 50 key on,will act funny.I have to insert key and hold in starting posistion for 10 seconds to start.After that no trouble till next 50 key on.
Been through 5 starters since November.Assuming it was starters.Could get a Bosch starter,they sent wrong starter.

That still has the bladed type of key right, not EIS?

smart key looks like a w126 key

Probably smart key is failing. There is a small coil at the front edge of the circuit board in the key. If the key is dropped and you lose good connection, you get intermittent recognition by DAS. New smart keys seem to be running in the $200-$300 range.

this key is 2 years old.How often to change batteries?

I change mine once a year but batteries only provide keyless access. They aren't involved in starting the car.

will try cleaning ground to starter.I just hope its not the ignition switch.Lots of moola.

A smart key looks generally like this, no blade goes in to the ignition, is this what you have really?

http://mbworld.org/forums/attachment...n-smartkey.jpg

Because I thought all the 140s used a switchblade-style key, generally like this:
http://img.auctiva.com/imgdata/1/3/0...4679166_tp.jpg

its a w140 key,the dealer parts guy called it a smart key,he said the car had to know the key to start

Right, that's all part of DAS though. Only reason I brought it up is I think this has the cartridge style ignition switch, these are prone to failure. It would help to be able to see if you are getting a signal to the starter when it fails. Cheaper to test than keep buying starters.........

I think that too.Do you replace ignition switch and lock?
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If it is the style switch that I think it is, no, you don't need the lock. Compared to a lot of MB ignition switches it is rather easy to replace. Hard to get the underdash trim off, other than that not too bad. Still I'd recommend trying to test something, rather than replace parts. Same thing happens and then you're pissed at me.

can't I put meter on it when it acts up.Put meter on solenoid? I have jumped the solenoid when car acted up.
Now I just hold 5,0r 6 sec.

My daughter has a failed Smartkey for her 1999 C280 and now has 2 new keys that still give her occasional start problems. I am going to open up the old key and see if there is anything obvious that I might be able to repair.

Anyone open up one of these keys? Do you just carefully pry it open?