I had my car off the road for some time doing maintenance, updating, tidying up which included installing a new alternator (old one died).
Anyone who knows 100A alternators for MR2s knows how difficult they are to find and as my old one appeared to be an aftermarket unit, rebuilding it was problematic.
After finding and buying one from the USA (there's another story in that), I installed it.
Anyway, after waiting a long time to turn the key for the first time I knew immediately something wasn't right when I had the battery/cooling fan/cat converter warning lights illuminating when the car was running.
Here are the tests I did:
1) brand new battery with good terminals/connectors
2) tested battery with multimeter and getting no charge (~11.9v running)
3) Alternator belt is good and proper tension
4) checked relevant fuses (ECU-IG, ALT sencing etc and all good)
5) unplugge the round 3 pin plug from back of alternator and battery/cooling fan warning lights go out on dash
6) Unplug the 3 pin plug from alternator and with car ignition in ON position get voltage ~10.5-12v at the 3 pins
7) As per service manual, remove cable from B terminal and attach positive of ammeter to B post and negative to cable = get a reading of 0.21A (manual stipulates under 10A is correct).
8) Put voltmeter to B terminal and ground negative terminal getting a reading of 0.54V (this is bad, should be charging volts so 12v+)
9) As per service manual, conduct a full field test (grounding terminal F) at the rear of the alternator and test voltage output. It drops slightly from aforementioned 054v (indicative that regulator is not at fault I believe)
Now I feel I/most others may reach the obvious/most likely conclusion but I'm after any advice from knowledgeable minds on other tests or strong opinions on what's at fault.
I look forward to some comments and a few less grey hairs at some point.
post edited by MG_MR2 - 2018/12/04 11:17:31