intermittent starting issue-please help

[Datuk]

Hi All,

Thanks in advance for your collective diagnostic knowledge.
I've got a '69 280SL unrestored.

It starts exactly (current as of last 14 tries) 50% of the time.
Battery is new.
Half the time---
Key in position 1 gives red light on dash.
Postion 2 one click, one crank then everything goes out.
Subsequent attempts immediately following yield no light or even click or crank.

Leave the car for a few days....turns over perfectly.

Any advice on what is worn and needs replacement?   I've got a friend who is handy with MG elelctrical, or should I shell out the $$ for the independent service center?

Thanks,
Scott

[Tyler S]

First and foremost start with checking your battery connections at the battery and at the starter motor.
Turn on your headlights and observe them during the fault. If they too go out then its a battery connection/cable issue. If they remain lit then start looking at the ignition switch.
There is also a connector block on the lower right side of the oil pan that could be damaged/corroded.  This feeds the entire fuseblock of the car.

[Datuk]

Thanks!
I'll start at these points this weekend.

[Mechudo62]

I agree, it sounds like a loose connection to the battery, check for faulty battery connections first. Also, check fuses in fusebox one by one and make sure they are clean and make good contact, sometimes they can get dirty with years of gime build up that cause electrical gremlins...

[ja17]

I agree, start with the battery.  If you have "bolt-on replacement ends" on your battery cables at the battery, take them apart and clean them. Often times the clamping section (at the cable) of these loses contact, while the connection at the battery is good.

[RAY]

I had a very similar problem and when i moved the earth strap it would start first time, could never really see a problem with it but replaced the whole thing and never once had a problem since !
Ray

[BaronYoungman]

I agree with the battery as the most likely suspect but if that does not get you results,  I would  think that your ignition key and mechanism might be the next most likely fault.  They do wear out and you get a sporadic connections.
Bob