starting blues

[Joe]

Well, I've really been looking forward to this day. After a lot of work, I was going to start the car and prepare it for a trip to the alignment shop. Trouble is, it won't turn over.
The starter doesn't engage. I don't get the familiar clunk like the solenoid is bad, but a sound between a clunk and a click, if that makes sense.
Here is what I've done and what I know about the electrikery stuff.
1. The alternator is new. It has a three-pronged plug on the back instead of the three nuts like the old one. I made a note of connections on the old one and spliced the wires which went to the nuts on the old alternator to the wires going to the plug on the new one. I checked continuity between the three positions on the plug and the plug on the regulator, and all is ok. That is, DF goes to DF, D+ to D+, etc.
2. Wasn't sure where to attach the ground wire that came off the old alternator, so I fixed it from a screw on the back of the alternator (not a lug, for sure), and connected the other end to the bracket which hold the alternator in place, and on which it swivels when it is tightened. When I checked for continuity between the brown on the regulator plug and the car body, there was no continuity, indicating the alternator was not grounded. I then ran a separate wire from another mounting hole on the alternator to the bolt that holds the horn in place. Now there is continuity between the brown at the regulator plug and the car body.
3. The battery is new, as is the terminal connector for the + side. I cleaned up the various ground wires.
4. The starter has been overhauled and the solenoid is new. According to the BBB, there is supposed to be a ground wire from the top starter bolt to the car body, but there is no such wire evident on my car, nor do I recall there being one when I removed the starter a couple of months ago. I took the starter out again today and looked for this wire, but cannot find it.
5. With the ignition key on, none of the guages works. The red light in the center cluster comes on, and no other light comes on. I have had all of these guages out and put new bulbs in everywhere.
6. I put a new back on the ignition switch, but started the car after that, so don't think that is the problem.
7. All of the fuses look ok.
My understanding is that operation of the starter is sort of independent from the rest of the electrical system. I'm suspecting the starter is not grounded, but being attached to the bell housing with a couple of hundred foot-pounds of torque would effect a pretty good ground, I'd think.
Any advice as to how to proceed is appreciated. Is there a chance I left a wire under the dash disconnected, and this is the problem?
Joe

[Cees Klumper]

Just a few guesses here: does the fuel pump start to run when you turn on the ignition? The bell housing is made out of aluminum and I will demonstrate my lack of knowledge here by confessing not to know whether aluminum conducts electricity or not. So perhaps it could be a lack of ground. What you could try is to test the starter in place by connecting a power lead directly to it, or take the starter back out (that's a difficult job though, right?) and see whether it will work on the bench.

Cees Klumper in Amsterdam
'69 white 280 SL automatic

[ja17]

Hello Joe,
The starter will work independant from the alternator. Make sure your battery is fully charged and making contact. Try the headlights when trying the starter. The lights should stay on and bright. Often times a bad connection at the battery cable end at the battery is the fault. If the cable ends have been replaced take them apart and clean everything up. Soda water will make everything brite and clean again. Commercial clean up and anti-corrosive sprays are available for this purpose also. Next grounding problems can be very perplexing, The main engine ground goes from the firewall to an engine/transmission bolt near the steering box. Make sure it is hooked up and tight.
Now if you have an automatic the nuetral safety switch or its control cable can be at fault. Have someone move the shifter and view its operation on the firewall. You can also test the functioning of the switch with a meter by unplugging the harness at the firewall switch. This switch dis-engages the starter in all gears except "P" and "N". This switch also operates the reverse lights and also inputs to the transmission three position solenoid. You should actually be able to hot wire one lead at this plug and activate the starter. This is frequently used as hook-up location by mechanics for remote starter control. If all else fails hook a small wire to the starter sonlenoid small wire, then touch it to the battery + post. This should bypass everything and directly engage the starter. Make sure that you are in park. Let us know what happens and we can go from there. Good luck!

Cees, Aluminum is one of the best conductors of electricity and heat. It does have some corrosive and fatigue (breaks) issues so it is not used as frequently as copper. Gold, lead, silver, nickle, are some of the other good conductors. Those expensive aluminum oil pans, valve covers, oil filter housings etc, all help transfer heat out of these engines. Aluminum radiators became popular after the W113 cars. Manufacturers figured out how to formulate antifreeze to  control the corrosion. It is less expensive than copper and conducts heat very well.



Joe Alexander
Blacklick, Ohio