'87 300D ignition/starting problem - PeachParts Mercedes-Benz Forum

Diesel Dan · #1 11-15-2006, 10:02 AM

This problem started yesterday. When I turn my key to start the car, I hear a "sproing!" or "click!" sound coming from the engine compartment (from the solenoid? A relay?), but nothing else happens. On the 3rd attempt the car starts up. I know my car doesn't start in "Park", so that's not the problem - I'm starting it in neutral. What are the most likely suspects here? Where are they located? How do I diagnose which part is faulty? Usually I can do these kinds of simple repairs, but I've not been able to find an affordable repair manual for my car, so I sometimes don't know where things are located. I searched the forum archives, but the posts I found were from people who didn't even get a "click".

While I'm on the topic, how hard is it to fix the problem that prevents my car from starting in "park"? How much $$ is the part? Is there a tutorial somewhere?

Thanks everyone!

Jadavis · #2 11-15-2006, 11:23 AM

The click could be the solenoid on the starter picking up, but the starter is not moving.

Do the easy stuff first. Disconnect the battery, clean the terminals, grease the terminals with battery terminal grease (if you have it handy, don't worry for now if you do not), and reattach the terminals. Charge the battery if you can.

If it is not that then turn your headlights on and try starting while someone watches your headlights (or where you can see them shining on a wall). If the dim when you turn the key then the solenoid is picking up and trying to turn the starter/motor.

This assumes that the lights don't shut off when you start. I have not tried it before and my car is not running right now. (The intake manifold is off.)

If the solenoid is picking up and the starter is not turning then you might be looking at a new starter. Or it might be as simple as the starter is weak and the battery is also run down. Make sure the battery is completely charged up. Make sure the battery connections are clean and tight. I've seen a loose connector on a battery cause the exact same problem.

-Jim

Diesel Dan · #3 11-15-2006, 02:16 PM

Quote:

Originally Posted by Jadavis

The click could be the solenoid on the starter picking up, but the starter is not moving.

If the solenoid is picking up and the starter is not turning then you might be looking at a new starter. Or it might be as simple as the starter is weak and the battery is also run down. Make sure the battery is completely charged up. Make sure the battery connections are clean and tight. I've seen a loose connector on a battery cause the exact same problem.

-Jim

Thanks for your reply Jim. I suspect the battery is good, since I've not noticed any slowdown during cranking, but I'll check the connections, and do the headlight test. I did have to do alot of cranking to prime the ("self-priming") fuel system when I was troubleshooting that recently, so maybe I wore out an already weak starter during that process. I've since learned a better way to prime the fuel system.

Anyone have a response about the problem with not starting in "park"? What is involved in fixing that problem?

Thanks again!

Dan

rrgrassi · #4 11-15-2006, 02:48 PM

Neutral Safety Switch could be acting up. Probably not since you can start in nuetral. Can you move the selector around a bit while trying to start the car? Could also be the selector bushings wearing and when in park, not allowing the NSS to close.

Diesel Dan · #5 11-15-2006, 03:00 PM

Quote:

Originally Posted by rrgrassi

Neutral Safety Switch could be acting up. Probably not since you can start in nuetral. Can you move the selector around a bit while trying to start the car? Could also be the selector bushings wearing and when in park, not allowing the NSS to close.

Is the NSS accessed from inside the cabin, by taking apart the shifter assembly? Or is it accessed from underneath? What does it look like?

rrgrassi · #6 11-15-2006, 04:21 PM

Replacing Neutral Safety Switch in W124

Use this link, it has some good info on the NSS

Diesel Dan · #7 11-17-2006, 01:08 AM

Well, I went to take the starter off, and found that the nuts that hold the wires on to the solenoid were a bit loose. So I tightened those down, and cleaned up the battery terminals and tightened the leads. It started twice in a row without a hitch, so I'll continue to drive it around and see if the problem reappears. It's been one of those intermittent problems, so the only way I can think of to route it out is to keep driving and hope that if the starter is going to bite the dust, it does it in my driveway, and not on the other side of town. I suppose I could get the starter tested at my local Autozone, but I'm not sure if that test will identify all possible starter problems.

Jadavis · #8 11-17-2006, 02:45 AM

I would bet that you have now taken care of it. You would be surprised what problems loose leads will cause.

Congrats!

-Jim

aersloat · #9 11-18-2006, 01:29 AM

Probably not the NSS. Do the bushings-- just a few dollars for the parts. Look on the wiki as there is a DIY for the process.

Diesel Dan · #10 12-11-2006, 10:40 AM

To date, I've not had any more problems with the starter/solenoid. Looks like the problem was indeed the loose nuts holding the wires on the solenoid. Yay! A cheap fix, for once!