is it the orginal wire loom and mostly original connectors? (if all new ignore my post)
Has the weather been cold and damp or humid and rainy? or rain then hot then cold overnight.
did the car ever live near the beach?
weather that makes corrosion in connectors damp then dry then damp again will spoil old car fun eventually.
i ask because my own car lived by the beach in Australia and then was moved to London UK which does have its fair share of the above mentioned weather
on moving from HOT beach atmosphere to damp london I had 2 years of similar behaviour.. what worked today, didn't work tomorrow but might work again next month....
this is my list of corroded green connectors all of which looked great until you pulled them apart, all of which have worked again perfectly well for the last 20 years once cleaned and smeared with a thin layer of vaseline
1) connection of the ignition switch, 4 wires (went on fire.....)
2) the connectors that attach each end of the fusible link ( i had aftermarket rubbish with 1/4 inch spade connectors)
3) all of the connectors in the 2 bulkhead connectors that my car has. The plastic plugs acted like a bath of condensation. they sit there in the engine heat and cool off in the sub zero garage and over the years condensation driven corrosion builds up)
4) the clips for the fuses, green patches, the metal caps on the ends of the fuses rusty patches, the connectors onto the back of the fuse box green white black dust.
5) earth strap between engine and chassis looked like it had spent time on the Titanic, both ends.
6) the aftermarket "clamp on to wire" positive side battery clamp... these are rubbish get a properly crimped and/or soldered one (acidic battery breath will kill a clamp on one)
each one of these problems discovered as and when something randomly failed for no obvious reason over a period of 18 months... i had a small fire in the connector for the ignition switch and my fuse box melted at the fuse for the heater fan.
i got damn good at hot wiring my car and purchased a C02 based fire extinguisher to compliment my foam one...
it's salty "sea air" lifestyle for the first part of its life and then the wildly variable stinking hot and humid to ,solid ice for days in winter, London home, played havoc with connectors that were hidden away in loom wrap or modular plastic plugs
once I'd cleaned the lot, everything worked better, and i still have some of the parts I took off by way of diagnosis, that ultimately had nothing but age and patination wrong with them.
Perfect voltage measured BUT a lack of current in its veins were the problem. most of the current was just heating up the green corrosion in the connections rather than being put to good use..
The starter did its job throughout but often didn't start the car...
1) you are not alone in your problem
2) all of the advice in posts above is good and potentially provides a fix ......BUT>>>>>
3) if all else fails, a day with an old toothbrush, some vinegar or some liquid brass polish and a tub of vaseline may pay dividends.
Make sure you wash the contact cleaning "products" off before you vaseline it up for the next 20 years....
my thinking is, you didn't change anything nothing failed when under stress
something failed while you were away......
and the only thing that happens to your car while you are away is damage caused by oxygen moisture UV light and temperature changes
OR ...if very unlucky.... some other human being...causes a problem.
Dave
