86 300E won't start - starter question - PeachParts Mercedes-Benz Forum

JFAZ · #1 04-19-2004, 02:00 AM

Hi everyone!

I do not know what I would do without this forum (it is sooo great)! So here it goes...

I have an 86 300E that is having some starter issues (or what i believe to be starter issues). I went to start the car today and it would not start. I then attached a multi-meter to the battery and it gave me a "full-charge" reading, next I had someone turn the key while I had the multi-meter connected to the battery and there was NO shake or drop of the needle so it can't be my battery right? The battery is appx. 3yrs. old, and I coincidentally replaced the negative lead to deal with a different problem about six months ago so the terminals are very clean. I also disconnected and then re-connected my battery leads just for the heck of it. Nothing. Then for no reason in particular I put the car in Neutral and pushed it forward in my garage a few inches; turned the key and voila, started without any hesitation. I have no idea how pushing the car could have affected the starter though, so am I correct to replace the starter next? BTW, my car has 123K miles, I have owned it since 2001 when I purchased it with 74K on the clock.

I have already searched the forum for "300E starter" and I was not able to find the info. I was looking for.

Thanks in advance for any suggestions anyone might have. Have a great day!

#2 04-19-2004, 08:05 AM

The fact that you couldn't find any posts regarding these starters gives you a pretty good idea how reliably the typically are. The original starter is in my 300E after 267000 miles and has never been touched.

When the starter is failing to work, you need to measure the voltage at the starter, not the battery, while you have someone turn the key. If there is voltage at the solenoid, then you need to check the solenoid and starter, if there isn't, you need to go backwards through the switch and see where the voltage is not making it.

You really need a wiring diagram. The one in a Haynes manual should do.

Good luck,

greenacres2 · #3 04-19-2004, 06:49 PM

Quote:

If there is voltage at the solenoid, then you need to check the solenoid and starter, if there isn't, you need to go backwards through the switch and see where the voltage is not making it

...and when you've traced the lack of voltage back to the neutral safety switch, do a search on how to replace it. (just a wild guess) The "what else should i do while i'm in there" job is shifter bushings. Do the electrical diagnosis first though, it's valuable to learn how.

Gilly · #4 04-19-2004, 06:55 PM

To me the whole scenario screams "shift linkage bushings" also.
Next time it does it, just hold the key in the "start" position, then while holding the brake, run the shifter back towards the neutral position and see if it cranks. Lots of time these bushing are worn and the neutral safety switch isn't in the proper position any more, even though the transmission is in park.

Gilly

plink49 · #5 04-19-2004, 08:42 PM

I experienced this exact problem in my '86 300E, but only during cold (below freezing) weather. Starting in neutral always solved the problem. I highly doubt you have any kind of starter/solenoid problem if this is the case with you. My guess is that there is a sensor going bad that tells the computer the car is in Park, and the lockout is in effect....and from my experience the sensor is temperature-sensitive. I'm not a mechanic in any way, shape or form...just using logic here.

Jackd · #6 04-19-2004, 09:22 PM

Looks like a typical neutral switch problem to me.
Based on what you reported, that would be the first think I'd look for.
This surely has nothing to do with a faulty temperature sensor.

JackD

Gilly · #7 04-19-2004, 09:55 PM

Plink isn't suggesting a temperature sensor, he's suggesting that the sensor (actually the neutral safety switch) is sensitive to low temperatures.
What I am suggesting is that the bushing or bushings (there are two) may be worn out, which is not allowing the neutral safety switch to operate correctly (out of adjustment due to worn out bushings).
One way that may help to verify this is if one or both of the bushings are worn out you'll here a mechanical rattling noise when shifting gears.

Gilly

mercbilly · #8 04-19-2004, 10:19 PM

Hi Everbody!
Just wanted to thank greenacres2, gilly, plink49, and Jackd for their input. I just moved the shifter around from park to reverse to neutral to drive and back to neutral and she started right up.
"Who are these guys, anyway" to quote from the movie Butch Cassiday and the Sundance Kid.
Mucho Thanks, and I'm sure I will be back for More!!

pesuazo · #9 04-19-2004, 10:20 PM

I also vote Neutral Switch.
Same scenario happened to me several years ago.

JFAZ · #10 04-19-2004, 11:11 PM

Wow! Once again the members at MercedesShop.com have come through with an overwhelming response to my question all while I was at work! Thanks everybody!

Like everyone above mentioned I just put it all together that my failure to start problem only happens when the engine is cold (meaning simply not running for several hours). After getting into my car this evening at work and it would not start I simply shifted to neutral then rolled the car back a few inches- seems to work everytime. However I did have to make several stops on the way home and therefore shut-off the car but when I returned it fired right up each time without even shifting to neutral- I am assuming because it was warm.

I am going to do a mass search focusing on the "neutral safety switch" and see what I come up with.

It is kinda crazy that to think this car has a starter that is good for over 250K. I like it.

I will keep everyone posted on my findings. Thanks!

Gilly · #11 04-20-2004, 05:04 AM

In all of these cases it will be in your best interest to check the shifter bushings. The "cause" for the failure may actualy just be these bushings. The switch may be fine, but there may be a worn bushing (or both) not allowing the switch to go into the proper position. So don't run right out and buy a new switch in other words!

Gilly

tabari3a · #12 02-16-2008, 01:09 PM

My 86 300E will start in any gear. However sometimes it will cut off and won't start. It dosen't make any sound, as if I haven't turned the key at all I've read a lot about the Neutral Safety Switch. Could that be the problem here even though the car will start in any and all gears. Any suggestions on how to determinie if it is the Neural Safety Switch.

Thanks,

Carol