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.

k40 and ignition switch are prone to wear,I replaced both,been fine for 5 years now

order good switch from here

brand new battery, connections are all clean, new as well , there is so little on the starter motor diagnostics here or anywhere, but that is where I am leaning as the issue. I am going to replace CPS , just so I rule that out , and as mentioned already replaced the cube relay on the K40 module. If I get the energy up this weekend I may try accessing the starter , at least to check the connections

This car is well cared for, 0 rust , 141K on the clock

Have someone look at the engine driven fan / drive belts to confirm the engine is actually rotating while the starter is " whirring ". I've seen the one way clutch in starter drives fail and customer state car cranks but won't start. Cold temps are a tip off as the grease gets stiff preventing the clutch from engaging.



A failed cat won't cause your problems.

you may be onto something 97 , that was the feelling I got when the whirring occurred, like it was not engaging, and it was cold. So that would require a replacement or can the starter be serviced ?

oldsinner, what do you mean by "ignition switch" the key way? this year has the electronic gizmo key

This car has "flick start" meaning the starter will keep on running till the engine fires, you physically do not have to hold the key to start. Just twist and leave it.

The starter will let go after 10 seconds of cranking and no rpm signal above 300.

If the starter is stopping midway, you need to hot wire the starter and test it for health. Remove the box cover and you will see the K40 relay, The center connector has a thick purple/white wire. Remove this connector and wire up a jumper from the positive jump start post. Apply 12V positive to this wire with it removed from the K40, the engine should start to crank even with key not in the switch. (make sure car is in P)

if it cranks good and fast. the starter is good.

Next up - check the display and verify that you see the gear indicator in the gauges. does it change as you shift from P to D?

if you see it disappear for a few moments, you have issues in the gear selector and it can cause this no start - and can also cause the transmission to "neutral" or go into hard limp mode.

If the trans passes, I would suggest you check the connector, wiring and also the CPS - the ECU looks for the rpm signal when cranking. if it sees a corrupt signal it will stop the cranking. (just like later chevy)

The starter drive is replaceable however it takes some tools and repair experience. The most direct route is a used or rebuilt starter unless you have a starter / alternator shop in the area.

Make sure the engine isn't rotating before changing any parts.

Whirring from starter + engine not turning = starter drive slipping.

Brief whirr then no noise / no engine rotation = starter control wiring issue or starter problem, needs further investigation.