Good evening all,

I have a 1986 Mercedes 300 SDL, 280,000 miles and it is not able to start. The car had beed running fine, and the battery is fully charged. The alternator is recently rebuilt. After driving her home one evening, I went out the next morning to go to work. The car would not start or turn the engine over. The glow plug light did come on , as well as all the normal dash lights. The only peiblem is that once the glow light went out, the engine would not turn over. Nothing, it just sits there with the dash lights on.

I had been experiencing a slow battery drain, but I always kept the battery charged. Not sure where to start looking? Any suggestions would be helpful. If there is anyone that could help. I don't think it is anything major.

Thanks in advance for your help.....

Ron

__________________

Try starting in neutral. If no go, move the shift lever a little ahead and behind the N position to see if the starter engages. Keep your foot firmly on the brake pedal while you move the shift lever!

Sixto
87 300D

Thanks Sixto....

I did try starting in neutral and it was a no go. Tomorrow moring I will try starting in near neutral. I will repot back. If it works, what would it mean?

Ron

__________________

Bad neutral safety switch if that's the case.

__________________
Allen Kroliczek
Oak Grove Autosport | Oak Grove Autosport
01 G500, 82 300TD, quite a few more.....

Is that hard to replace?

__________________

If the starter engages when you wiggle the shift lever, likely the shift rod bushings are shot. There's a bushing at either end of the rod between the bottom of the shift lever and the transmission. When the bushings go, there's slop in the shift lever. It should be tight, as in no fore-aft slop.

I forget where the NSS bypass connector is in a 126 but it must be somewhere ahead of the battery. You jump a couple of open connectors to engage the starter. It's one way to determine if the problem is the NSS or starter.

Sixto
87 300D

NSS isn't difficult to replace in a 126. The shift lever has to come off so you might as well order bushings at the same time if you need them.

The NSS is the black device with the round connector towards the tail end of the transmission -



These are some tips for replacing the shift rod bushings - PeachPartsWiki: Shifter Bushing Replacement

Sixto
87 300D

Okay thanks....

__________________

If the starter does not engage ( engine not turning over ) in park AND in neutral position then it is unlikely to be the NSS switch. It is common for NSS to have pitted contact in Park position but not in Neutral position. It could be the starter. I would try to check whether the starter's small terminal ( solenoid terminal ) gets 12V when you turn the ignition key. Changing the NSS is not difficult but access is tight. I would not go there until you have checked out the starter.

__________________
Not MBZ nor A/C trained professional but a die-hard DIY and green engineer. Use the info at your own peril. Picked up 2 Infractions because of disagreements. NOW reversed.

W124 Keyless remote, PM for details. http://www.peachparts.com/shopforum/mercedes-used-parts-sale-wanted/334620-fs-w124-chasis-keyless-remote-%2450-shipped.html

1 X 2006 CDI
1 x 87 300SDL
1 x 87 300D
1 x 87 300TDT wagon
1 x 83 300D
1 x 84 190D ( 5 sp ) - All R134 converted + keyless entry.

I did try starting the car in neutral and park, as well as near each gear, and no luck on starting. Next I need to know which post to make contact with to jump the starter, or check for 12 volts. I did find the junction box.

__________________

Are there any fuses related to the starting process? (Started, Neutral Safety Switch, or etc?)

I've had some issues with the circuit board and plug. The plug is broken (Center "D" part) so I tried a few configurations to get all electrical items are working. Now they are all working. The car was stating for about two weeks. One day it didn't. The entire dash lights up and no start. I've checked the NSS by moving the gear shift around and no change in the outcome. My card in the fuse box is missing so I can not look it up.

Any assistance would be greatly appreciated.

Ron

__________________

Are you positive your battery is well charged? Terminals clean? Do you heart a click from the starter solenoid?

You might need a friend that has a little more knowledge to help you out. All the main connections should be cleaned and treated on an old car as preventative maintenance.

Not sure if oxidation builds up in climates like Arizona. Varies I suppose with geographical location. Your description could apply to a lot of things being the issue.

I had a NSS fail completely. Jumping NSS wires allowed the engine to start so I replaced the NSS. Should be easy to test once you have the pins outs for a 126 NSS. The NSS area in a 124 is a Japanese hotel room next to the ballroom around a 126 NSS

Sixto
87 300D

Yes the battery is charged completely. It is a almost new one and I keep it charged with my trickle charger. I can hear the clicking sound you mentioned. I question the NSS because I had the entire transmission refurbished less than a year ago.

What is the clicking sound?

Thanks to tou both for your responses...

__________________

The clicking is either a starter relay (not sure if a 300SDL has one) or the starter solenoid trying to engage the starter. When you get a click but no start, it's often due to a weak battery. Since you seem to have eliminated that, you either have bad connections (bad grounds are common) or a bad starter.

__________________
Whoever said there's nothing more expensive than a cheap Mercedes never had a cheap Jaguar.

83 300D Turbo with manual conversion, early W126 vented front rotors and H4 headlights 400,xxx miles
08 Suzuki GSX-R600 M4 Slip-on 22,xxx miles
88 Jaguar XJS V12 94,xxx miles. Work in progress.