Did You have the same problem..NO Crank..or did the engine crank and have NO Spark?

I Thought the EZL only provides Spark and the starter circuit does not go into EZL?

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MBENZNL.com

The problem is no crank, and has nothing to do with engine management.
The problem is in the starter circuit, meaning ign sw >NSS sw> K38 Interlock sw > starter.

k38 is fed by fuse 5 , so that is where to start. P and N are next test for NSS...... and X27 plug for power is starter sol feed.

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A Dalton

That's what I can't remember...

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1994|040|W124.036|E500
http://www.mbworld.org/forums/image....ine=1216527951

OK guys - moving a little fast so let me slow down and recap:

All systems go, but no crank with new battery having 12.6 volts cold and full cranking amps available.
Cannot locate any connectors on the firewall between the engine and the brake booster.

Is the next test request to put the car in N and try to start?

Thanks

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94 E500 (Silver/Black)

Ok
X27 is a jumper point we use to test the starter, but the E500 has it some where else and the CD does not show it. They show it next to reservoir, but it is not there and I forget where it is on that model [ someone?]

Anyway, here are a few test for no crank:
First, turn on the headlamps and then attempt to crank...do the headlamps go out or severly dim?

If yes , you have a bad connection feed or bad battery voltage.
Next, try 'N" instead of P...Turn the key with left hand and hold it in the start position as you try the gearshfit lever around the N gate position..if yes , then you have a bad NSS. [ Neutral Saftey Switch]

Next is to take out fuse 5 , I don't care what you think about the fuse, replace it. That feeds the K38 relay and if it has a bad/poor connection, the K38 drops out of the circuit and you have your conditon. That is starter interlock for ATA Alarm system.

Try those first.......

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A Dalton

Arthur - thanks, but with thanks youget more questions.

Went out and re-attached the battery. Moved lever to N, turned key while aggressively wiggling the lever and presto - she starts. After let it run for about 5 minutes, turned it off, and car restarted when in P.

New question: What is the recommended next step so I know it will start every time? Did I clear a logic problem that is gone or do I have impending doom waiting for me?

Thanks

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94 E500 (Silver/Black)

Suspect is NSS.... BUT....b/c you can have an intermittant problem, you will have to try it a few times to see if you can replicate the condition
B/c you replaced the battery, did you , in replacement, cure a possible bad terminal condition..or did the NSS have a bad contact and cleaned itself off with the gearshifter movement ??

Usually , if you get no crank on N/P and you can get a crank with the N movement trick, it is the contactor bar in the NSS that is full of dirt from the road and weather. The true test is to jumper the NSS feed wires at the plug near the gas pedal when the condition presents , but at least you now know how to narrow it down.........
Still replace fuse 5 and also be aware that the k38 contacts sometimes will recover from a bad conection by simply Locking/unlocking the car several times for alarm acivation...if that does the trick, then the K38 contacts are suspect. That relay is behind the sreedo and a common problem. Many just jumper it permanently.

Intermittant problems have to be approached in this fashion...

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A Dalton

Thanks Arthur, I have printed out the thread for future reference. I'll be back if it rears it's ugly head and I cannot get through the process without some help.

My thanks to all.

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94 E500 (Silver/Black)

I have written several tutorials on this system and that all can be found by using the search feature by using " K38 ".
It has the exact series chain , from Ign sw right thru to Starer soinoid..... so that will help you understand what is entailed in the Starter Circuit.
It is simple a chain of components in series and any one fault in that chain results in No Crank.....but it is actually a very simple circuit once you see it.

The power for the starter sol starts at the battery, goes to the ign sw , then to the K38, then to the NSS , and on to the sol. Any break in those components stops power from reaching the starter...simple

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A Dalton

Arthur (or anyone else),

Obviously I confirmed that the NSS was the problem by performing the gear lever wiggle in N. After two days of starting OK in either N or P, this morning it started in the garage (in P no less), went out, and 2 hours later will not start again (time for that AAA tow truck - again). Does the NSS or K38 circuit have anything that is temperature related? All of the previous starts were at 60F or better, and this morning when it did not start again in N or P with the aggressive "wiggle" it was 40F.

Oh, BTW, once warmed up after requiring the N start, it starts in P again if the system is warm.

Any thoughts?

Thanks

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94 E500 (Silver/Black)

Just change the NSS..it is a common repair............

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A Dalton

Thanks again Arthur.

I have just hit the send button and ordered the new NSS, the two bushings and retainer clips. If I need anything else let me know otherwise enjoy the remainder of the holiday.

Steve

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94 E500 (Silver/Black)

Arthur: As usual, that is a very informative explanation on the starter circuitry.

MBSteve: I think my NSS once went bad due to oil leaking into it and dirt collecting over a period of time. I'm sure this is not a recommended fix, but over the weekend, while you're waiting for your NSS to arrive, you might want to get under there and flood the switch with electrical contact cleaner, then run the gear selector through all positions a few times. I found that this fixed the problem at least for a week or two.

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1993 400E, 256,000 miles (totaled)
1994 E420, 200,000+ miles
1995 E420, 201,000 miles

I'll give the contact cleaner a try. Is there a recommended/easy way to get to the switch with the car on the ground and not up on a lift?

Thanks

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94 E500 (Silver/Black)

Jack up the front of the car. The switch is on the left side of the transmission.

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1993 400E, 256,000 miles (totaled)
1994 E420, 200,000+ miles
1995 E420, 201,000 miles