97 E320 Starting woes
 

I have a 97 e320 that's exhibits periods of failing to start.
What I mean is, Car has 40K miles, Brand new battery, New Plugs, and at any given time, It will not catch when cranked.

It will be ok, no problem then out of the blue, Crank for however long you hold the key( not long) but won't catch to start.

Wait a minute try again, starts.

Other times, go for days no problem, One time won't start, then wait a few seconds, start on 3 or 4 revolutions.

Can't determine if it temp related, Can sit for a while in the cold, It acts up. Other times, right up.

Sit for a 10 minute period cooling off, Won't start.
Others times go in store, come out, first try, starts.

No rhyme or reason.

Any thoughts or ideas to check?

Mike

Transponder key?

When this happens,keep cranking and look down at the check engine light.It should be illuminated.
If it is not,the ME control unit is not recieving power.
Could be the ignition switch or the k40 relay.
Brian

e320 starting woes
 

Brian,

It is lit.

Thought maybe it was the switch also. Because it is so imtermittent I'm going to try to jiggle it a little while turning to see if it makes a difference.
what does the K40 relay do, (In 944 terms I'm hoping it's the DME relay.

It's almost as if I wish it would break so that I'd know what's the matter.

John, not sure what you meant be transponder, but this model year has the switch blade type security old style key.

Thanks, Mike

Brian is correct, the electrical portion of the ignition switch is a problem area on these newer cars. AT times they don't power up the key-on circuit(circuit 15) to the coils & then you have a NO-start. Look closely at the warning lights when this happens.

Re: e320 starting woes
 

The switchblade key has a transponder chip in it, and I've seen them fail. Just something to rule out...

Thanks, John

Wasn't sure what you meant.
Kinda wondering how the transponder works seeing the stand alone Key, doesn't have anything.

Mike

Mike,
The check engine light will only not come on when the car wont start.
The k 40 relay is the relay that supplies most of the control units with power.
The stand alone key does have a transponder in the plastic part.
It was a joke that it is a male key,because if you hold it blade pointing down,it has balls!

To update,

I dropped a new Interstate MT 91 Battery in the back seat when this happened and haven't had a no start in a while. (fingers crossed).

The old battery was a MB dealer replacement, that was less than 2 years old. The original owner drove less than 1500 the past year and less than 3K in the last 3 years, which leads me to think it didn't have a good charge, even after a 500 miles return home trip. (I'm a believer in chargers for a good charge rather than relying on the alternator.)

Mike