99 E320 Crazy issue with starting
 

On my 1999 E320 ,daily driver , 141,000 miles , with all service intervals followed
l'll start by saying I dont think this is a CPS issue. It can happen at any time, at any temperature and when it does it presents as a no start , no crank issue.
I have a brand new battery.
So here is how it goes, place key in ignition, shotgun release occurs car may or may not turn over and then nothing . Turn key to off and then to on and it starts , sometimes on the next turn sometimes after several. Runs fine after that ,may not occur for many days or may happen several times on one day. Never had her not start , but that is not reassuring . No CEL
very puzzling

Agree on not the CKS, and it doesn’t sound like a key issue. See if this link gives you some ideas.
2000 E320 K40 relay (or is it???) - Mercedes-Benz Forum

In the passenger side under hood box there should be a row of 6 or so fuses. In this box there should be a 8 ish wire plug. Look for the large purple wire, this should be the starter trigger wire. Hook up an incandescent test light and see if you get power there while trying to crank.

Thanks. Ill check

Not as familiar with your E320, but on my 95 I had intermittent issues like this from the immobilizer relay which interacts with the alarm to disconnect start function. Its behind the speedometer under the dash..Some just jump this relay to eliminate the possibility of failure. Good luck.

Just for completeness, on most but not all MB models:( the E320 W210 / C280 W202 / SL320 R129 follow the below )

96 was the last year for a starter interrupt anti theft.

97 went to a DAS that prevented the computer from firing the injectors but it would crank.

98 + went to the smart key ( no metal key ) and I think it retained the no injector firing strategy.

Crazy thing is mine does not turn over when this occurs. Just perhaps a start of a turn over but nothing more.

OK this one is getting more frustrating Today , early morning , cold out, had not driven it in several days
Turned the key and acted like the starter would not engage, or no spark , or something not right --sounded very strange, after several rounds of this whirring noise then it started . Runs fine , no CEL, although I had it checked to make sure no codes were present , there were none. The rest of the day it started up with out issued, EXCEPT after a 12 mile run I put key in turned over once then nothing , turned key off back on and started . I replaced the relay that is known to cause issues , without help ( it did it one more time after that)

Now Im thinking CPS , but will those symptoms occur ( no start, trouble start) when cold?
I don't THINK it is the starter because when it does start , 98% of the time it is a perfect starting sequence. Turn key - start car....

I do know one of my catalytic converters is failing ( rumbling) but I doubt that is related . no power issues , no mpg issues

Thoughts ?

I'm afraid I can't offer anything of use but I'm interested in the thread as I'm considering buying one of these. Can you explain what you mean in your fist post with a reference to a "shotgun release"?

- Peter.

On the passenger side firewall open the box and the first set of controllers (twards) the radiator is the K40 relay. On the left side is an ice-cube relay. The part number changed in early 2000s - the dealer can help you with that. Its not expensive but is the root of all evil on 98-2000 W210. I did pop my box apart and hit all the suspect solider points too. To replace the entire unit is fairly pricey. The ice cube relay was $11.XX 2 years ago at dealer.

I'd try using a spare key for awhile to see if that is the problem.

not the key , I tried em all . TX - replaced that ice cube relay, but did not check the joints I am leaning to the starter just because nothing else makes sense , and I understand it can be a PIA to R/R

Peter - the shotgun start is putting the key in the ignition and hearing the steering lock disengage , it sounds like loading a shotgun

I am a little confused. First you said:

Now you say:

Which seems quite different. Does it crank or doesn't it crank?

That’s just it today it turned over but would not start. The other times it gave me a 1/4 turn of the engine then nothing

An obvious question is what is the state of the battery? What is the resting voltage? What about battery cable connections and what about the starter itself? I think if it cranks then the EIS is OK.