'97 E320 no start - no crank
 

My '97 E320 is giving me intermitten starting problems. I will attempt to provide as much relevant information as possible.

'97 E320 w/156K miles
3 times it has failed to crank, each time all warning lights on instrument panel illuminated normally, battery voltage normal, all other electrical items functioned normally also.

I have 3 ignition keys, all 3 keys were used to attempt starting with no crank from all.

Last night it would not crank again, I hauled it home on my trailer and left it sit overnight. Went out this morning put the key in the ign. switch and she fired up normally, with no hesitation.

Thanks in advance for any information to help with my intermitten problem!

Chet

Possibly a bad crank position sensor or a worn gear shifter bushing telling ignition that the trans is still in gear? Might attempt starting in Neutral next time...

<<Possibly a bad crank position sensor or a worn gear shifter bushing telling ignition that the trans is still in gear? Might attempt starting in Neutral next time...>

Good avice , except for Crank Sensor...He states it does not Crank, meaning Starter Circuit mal-funtion.

I had a very similar no-crank condition in my E300 ('98 W210 Chassis) which I found to be a bad relay. It was located under the hood, passenger side in the box near the firewall containing fuses and relays. I found it by accident essentially when one time I had the no-crank condition and then I tapped each component in there with the butt-end of a screwdriver and tried to start each time, after I hit the "right" one it started right up...then I removed the relay and it would not crank just like it was at fault.

The dealer stocked the part and it was only about $25 IIRC (a small black cube relay with 4 contacts on the bottom)...I will try and find that old post and see if I have a part number. I'm not sure if the E320 uses the same electronic controls but I think it does...mine was heat related too...it would fail when it was very hot out and after the car was warm...never failed when the car started first start of the day. It's been over a year since I replaced it and never once did I experience the same problem so it was a 100% fix.

I think that is the K-38 relay.. it is starter interlock for ATA System. Many guys jump them as they are high fail rate item. [ They used to be behnd the cluster, so I guess they moved them out front for sevice convienience.]
Good Call, NH


The earlier ones [ late 124] also had that problem if fuse 5 or 6 had a poor connection, as that was power feed for that realys coil circuit.. A simple twist of the fuses solves that.

Thanks for the responses, I did attempt to start in both Park and Neutral with no joy.

I also moved the car forward and aft with the key on and the transmission in gear, althought we all know with an auto trans this is hit or miss if it will produce and results.

As far as heat related, no correlation as of yet.....twice when the engine was cold and once while hot.

Also on each failed attempt to start, no clicks, no dimming of lights, no evidence of current draw.

I am open to any suggestions.

Thanks again for all of your inputs!

Chet

Thanks

Also, the ignition switch feels normal when rotated and the spring back feature from the start position works as designed.

Chet

It doesn't have to be heat related to be that relay...
 

Don't let the lack of it being related to heat indicate it's not the relay I told you about...try opening that fusebox and tapping lightly on the cube relay in there and see if that causes it to start.

Like Arthur Dalton said, it is a common fault and the fact that my dealer stocked the part speaks volumes since they almost never have anything in stock unless they go through them practically daily.

Mine acted just like yours, like the neutral safety switch had failed. The NSS is inside the 722.6 tranny so hopefully it is not that with yours...my money is still on the little cube relay.

If it is not misbehaving now then why not just buy a spare relay and keep it in the car...the next time it fails to start switch it out. Like I said, it is a cheap part - only $25 and the part number is stamped right in the case.

Unfortunately the old post I had on this subject seems to have vanished from the system here...in it I gave the PN from MB and the exact cost.

Why don't you try to jump start it. It could just be your battery.

nhdoc, I will take your advice....I am all for changing the relay.

The only reason I added the additional information was to better supply troubleshooting info.

I was not ignoring what you or Arthur advised.

Also I will not be able to purchase parts until Monday, but it is up an running now.

Thanks again to all,

Chet

If you want to confirm you have found the right relay just remove it and try to start...it should do the same thing you find it does when it won't crank...everything works fine until you switch it to the start position and then nothing happens...that will at least tell you that you have the relay I am referring to.

Good luck.