I changed bushings & clips for both ends of the shift lever rod, and replaced the Neutral Safety Switch with a real Mercedes part. I'm getting my reverse lights to come on, which is making me think that the NSS is indexed to the gears correctly, and is working fine, and I've tried starting the car by moving the shifter around just in case the indexing was off a bit, still no start. I've been able to short circuit the starter using a piece of cable in between two terminals in a box on the passenger side wheel well, starts up fine. Battery is working...

I did have one moment, when trying to key start, just now, where by jiggling the key around, I heard a bit of crank, but just a bit and then it didn't happen again.

Does anyone have an opinion? I think the NSS is good, am wondering if my ignition switch is funny, since I jiggled it and something did happen once, although, I am definitely able to fire the glow plugs using the ignition key.

Also, when you jump start the engine using the cable at the wheel well terminal, are you bypassing the starter solenoid, or are you bypassing the key start voltage and supplying voltage directly to the solenoid?

Any other things I should know or try?

Thanks, Dave.

You're bypassing the ignition switch, not the solenoid. I'd jump the wires going to the NSS and see if it starts, if so, then you'll know its the NSS. There are threads on here on how to jump the NSS up above the driver's kick panel but I think they all apply to the 123. Search on purple wire NSS and I think they should come up.
It could be a problem in the key swtich. That's not unusual.

__________________
1977 300d 70k--sold 08
1985 300TD 185k+
1984 307d 126k--sold 8/03
1985 409d 65k--sold 06
1984 300SD 315k--daughter's car
1979 300SD 122k--sold 2/11
1999 Fuso FG Expedition Camper
1993 GMC Sierra 6.5 TD 4x4
1982 Bluebird Wanderlodge CAT 3208--Sold 2/13

Good advice in post above.

Typically when you work on your car and something else doesnt work, check the last thing(s) you touched. Perhaps you stressed a wire? Retry the connectors.

It is possible that the ignition switch is faulty. Common problem. I was in my SDL recently windows wouldnt go down. fuses good. I was in a hurry and drove windows up. Got to destination, finished errand, back in car, fired engine, pressed window switch by habit, windows go down.

Previously i had monkeyed and fussed and searched. Drive, shut off, back in car, start engine, press window switches, worked. I can only assume that there was an intermittent issue with the ign switch.

Best of luck. So much for a straight forward repair.

__________________
85 300D 3 pedal. Current project.
83 300TD (need rear wiper assembly dead or alive)
84 300SD Daily driver
85 300TD almost 400k miles and driven daily.
98 E300D *sold
86 300SDL *sold and made flawless 10 hour journey to new home.

Hi-
I have the same problem with my '83 300D. I now start my car (as well as rotate the engine for valve adjusting) with a heavy-duty momentary switch I mounted just under the dash within easy reach. I used 8 ga. wire to run to-and-from the two terminals on the passenger wheel well. I still start the car by turning the key to just before the 'start' position to activate the glow plugs, wait for light to go out, and then press my starter button. Works great and helps a ton when adjusting the valves. Speaking of adjusting valves- be sure you unplug your glow plug relay when using starter button to turn engine over so it won't start on you when you're adjusting the valves.
The H.D. button can be purchased at just about any auto parts store. I got mine a Kragen's. I did this fix 'cause I wanted to keep my keying the same on car- it also could be looked at as an anti-theft device!
Cheers!
Chris

Renntag, I also should check the connectors as you mentioned, but doesn't it seem as though the reverse lights indicate connectors are good, or is it possible that they are working but there's still a connection problem? I suppose that jumping the NSS wires wouldn't mean anything if the possibility of bad NSS connecters exist, because if I get a start that way, the NSS could be fine but with a connection problem. Yes?

by chance does your speedometer not work after you get it started and drive?
the SD has a cable under the drivers side kickpanel in the console. it likes to pop off, and prevent starting...

__________________
John HAUL AWAY, OR CRUSHED CARS!!! HELP ME keep the cars out of the crusher! A/C Thread
"as I ride with my a/c on... I have fond memories of sweaty oily saturdays and spewing R12 into the air. THANKS for all you do!

My drivers:
1987 190D 2.5Turbo
1987 560SL convertible
1987 190D 2.5-5SPEED!!!

1987 300TD
2005 Dodge Sprinter 2500 158"WB
1994GMC 2500 6.5Turbo truck... I had to put the ladder somewhere!

Thanks to all for the helpful info. I'll try jumping the NSS to see if its somehow bad. If I don't get a start that way, I'm assuming that I have an ignition problem or a starter solenoid problem. Does that sound right? I suppose I'll check around now for how to test those two things. Am I missing any other of the major potential failures in the circuit?

The starter button idea is GREAT, but, I have to valet park my car sometimes (I'm a drummer, so I sometimes do gigs where I use a lot, or there are valets at the location) and explaining it all to those guys is a bit hit and miss.

I'm not having a failed spedometer, but thanks for that tip in case it does conk. I'll have a place to start...

Thanks for all of your advice and help. I ended up needing to go to a mechanic who could trouble shoot the starter issue.

The problem was a faulty ignition. In the process, I've replaced the shift lever bushings and the clips to hold them in place, the Neutral Safety Switch and all of the fuses in the fuse box.

It was very elusive, as I was having these intermittent starts in P and N. Given that the shift lever bushings had shrunk and come out of their holes when I checked & replaced them, I figured that was the issue. In the process of replacing them, I broke the little arm off of the Neutral Safety Switch, so I was thinking that when I replaced it, I did it wrong, but in the end, I didn't. The really mysterious element here was that once I had the new NSS back in place, I got no start at all in P & N, so, something about that change out caused the ignition to finally fail completely. I wish I had a diagram of the electrical layout of that car that I could understand. It doesn't really make sense to me that a new NSS would cause ignition to fail finally, but maybe it makes sense when you can see the layout of everything.

I had thought that it was the starter or starter solenoid, but because I was able to jump start by short circuiting two wires at the little black box terminal above the passenger side wheel well, I was ruling those two things out as the jump start still engages the solenoid, and the solenoid then engages the starter.

My battery had been replaced this past winter, and I have a huge battery in there, so it wasn't that.

So there you have it. Instead of installing a new ignition, I've had a button permanently installed in the dash which attaches to wires which run to that little terminal box in the engine. It works great, and although I wish I had a new ignition instead, it does ad another element of safety regarding theft, as the key itself will now not start the car. Anyway, that's how I'm going to think about it!

Bad contacts in the ignition switch are a common cause of the symptoms you describe. Why didn't you replace the ignition switch instead of installing a push button?

__________________
1977 300d 70k--sold 08
1985 300TD 185k+
1984 307d 126k--sold 8/03
1985 409d 65k--sold 06
1984 300SD 315k--daughter's car
1979 300SD 122k--sold 2/11
1999 Fuso FG Expedition Camper
1993 GMC Sierra 6.5 TD 4x4
1982 Bluebird Wanderlodge CAT 3208--Sold 2/13