78 300d - PeachParts Mercedes-Benz Forum

gwenn · #1 09-09-2013, 05:06 PM

Hello, my sweet little car won't start. Drove fine today, I've been running errand all morning. Pick my son up from school and nothing! Thought maybe battery-got a jump, nothing. Have power to dash, windows and such. Turn the key and click, that's it.. Has been a good car so far.

78 300d
87 300td wagon

Skippy · #2 09-09-2013, 05:13 PM

Start by cleaning battery connections and inspecting the cables and the connections at the starter. If those check out it's pretty likely that your starter is going bad. Tapping on it before trying to start will sometimes get it to work a few more times before it give up altogether.

gwenn · #3 09-09-2013, 05:27 PM

ok, I will clean and check..if it is the starter, is that an easy replacement? I have a hard time getting to it from the top. I was trying to see the connection but couldn't. felt around a bit, haha. the car is old and sat for sometime. I have been driving it about 3 months. if the connection are bad but not the starter how do I determine this?

kerry · #4 09-09-2013, 05:40 PM

Jump terminal 1 and 3 in the junction box on the top of the passenger inner fender in front of the battery and see if it turns over.

Skippy · #5 09-09-2013, 05:59 PM

If the connections are corroded, dirty, or otherwise nasty looking, they are suspect. A good cleaning will reduce resistance and allow proper current flow.

Starter changes aren't terribly tough. I did my 240D twice. The first time took over an hour, the second time about half as long. The 300D should be similar.

cooljjay · #6 09-09-2013, 06:14 PM

A 78 doesn't have the terminal box on the fender.....you have to jump it at the starter...

How old is the battery?

I would take the battery into the local auto store and have it tested and charged....if it sat with that battery init....they go bad....

Did the battery light come on, that is on the dash before you start the car? And did it go off?

Getting to the starter in a non turbo is easy.....remove the air cleaner and you can get to the terminals....remove the battery tray and you get even more room for removal..

gwenn · #7 09-09-2013, 10:35 PM

had it towed home, and she started right up. tried again, nothing.. will clean battery and check connections, what else? where is the neutral safety switch and can connection problems with that be causing this bull****?

vstech · #8 09-09-2013, 10:39 PM

put the shifter in Neutral... or try pushing the shifter all the way forward in park with your left hand try to start it...

gwenn · #9 09-09-2013, 11:15 PM

I already tried that..no change.

vstech · #10 09-09-2013, 11:46 PM

OK, and you get a click when you try to start?

then it's unlikely to be the NSS, that leaves, battery terminal condition, cable condition, or wiring at the starter... the battery is the most likely, as without some SERIOUS jumper cables, starting a diesel is impossible with a dead battery. pull the battery out, and take it to an auto parts store for testing. if it tests good, clean the terminals, and the cables for perfect connection. then try it again. next check the other ends of the cables, make sure they are clean and tight, last would be the starter itself, and no... it's NOT easy changing the starter on these cars... especially in the snow belt salt road area you live in... them bolts are big, tight and nearly impossible to get to...

cooljjay · #11 09-09-2013, 11:47 PM

Could very well be the nss but to could be a bad spot on the commuter in the starter....the tow and pushing probably got the brushes to touch the sweet spot.....but it could be bad shifter bushing and/or nss.....as was said though, usually a nss or bushing you wouldn't hear a click....

ROLLGUY · #12 09-10-2013, 12:23 AM

Don't forget to check the ground strap from the transmission bolt to the chassis. If it is loose, it will cause intermittent starting.

Diesel911 · #13 09-10-2013, 12:46 AM

If you have Time drop by a Harbor Freight Store and pic up one of the inexpensive Electrical Digital Multimeters. If you get the Car Started again see if you Battery is charging.

I don't know if your year and Model has the Neutral Safety Switch Connector located in the same spot as on the Turbo Models; see the pics.

In the 2nd pic it shows where to use a Jumper Wire to bypass the Neutral Safety Switch.
I don't know if your Wires are the same Color or not but one set of wires goes to the Neutral Safety and the other set goes to the Back Up Lights.

In the last 1.5 Years People have been having issues with their Steering Colum Lock (that turns the Ignition Switch) and the Ignition Switch itself.

While it was still working in the Pic of the Ignition Switch the Contact Point on one side is burned off. In My case it was the inside of the Steering Colum Lock the tube that turns the Ignition Switch broke.
I replaced the whole assembly and it comes with a New Ignition Switch and Vacuum Shutoff Valve when you get the steering Colum Lock.

There is an Engine to Chassis Ground Strap under the Car about where your Feet Rest that could be checked along with where the + Cable bolts to the Starter.

The Starter is similar in design and function to the old AC Delco Starters that used to be on all GM Cars.

cfh · #14 09-10-2013, 02:43 AM

I had the same problem with a 300d (turbo) a few years back; it was a corroded ground strap - very easy to fix - just unbolted the ground strap at the frame, cleaned it up with a little sand-paper, oiled it, bolted it back up. - Ch