car start problem
 

I really don't like asking a non-Mercedes question here, but, this time, the problem I am having is not with my '84 300 SD, but, it could happen to any car, so I'll say that I am seeking general advice. Please let me know if you have any suggestions, since I haven't yet found a similar forum such as this for my Villager.

My other car is a 96 Mercury Villager van (so I guess you could say its still a 'Merc' :) ). It won't start, but has full power to the lights, etc. I took the battery out and had it tested - its fine. This is true despite the fact that my wife was able to have the car jump started when this first happened. I pulled out the starter motor and had it tested - its fine, too. I also pulled out the ignition coils and they tested OK. I checked the 'starter/inhibitor' relay and it tested fine as well.

The engine won't turn at all (although on my latest attempts I do hear a clicking noise).

Based on these symptoms and the fact that it did jump start, I am guessing that it is either the ignition switch or else a wire or cable between the battery and the starter that has developed some added resistance due to corrosion. The dealer doesn't even carry this ignition switch for sale without replacing the full mechanical key cylinder assembly and they suggested I bring the car in to them, although I have been somewhat determined to find this out for myself.

Anyway, if you have any general suggestions, I welcome them. Who knows, something similar may happen to my 'other' Merc(edes).

Thanks.

You might want to check your engine ground strap. I had a similar problem on my 99 Chevy Tahoe. In the Chevy design, the starter and ground wire is located too close to the exhaust manifold. After chasing the electrical gremlins for awhile, I removed the engine ground and found it to be brittle and corroded. Since most of my work is on boats, I used a larger size marine grade wire and some heat reflective tape to replace the engine ground and starter wires.

This is easy to track down using a voltmeter. While 'starting', measure voltage from battery post to post. If it stays high, e.g.12V, battery is good. Measure from battery post clamp to clamp, then proceed down the line. Common problems are poor contact at battery posts, or inside solenoid relay.

Steve

fixed!
 

Thank you both for your replies. The problem WAS the negative battery cable and it matched the symptom that I observed that there was about 0.3 volts between the ground side of the starter coil and ground (when they should have been at the same potential).!

Yet again, this great site and the helpful people on it helped me solve a problem, this time one that was not even on my Mercedes! :)