MR2 Alternator Upgrade?

General discussion about our beloved Tercel 4WD cars
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SinusoidalTendencies
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Posts: 151
Joined: Thu Sep 06, 2018 12:06 pm
My tercel:: 87 4wd wagon

Re: MR2 Alternator Upgrade?

Post by SinusoidalTendencies »

So voltage does meander a bit as the regulator gets it back to 14ish.
Seen over 15 with the beans off idle, but it comes back down soon enough. Drops to 13ish when the beans stop and recovers. Occasionally hangs 13ish when rad fan comes on. Was doing some wierd 12ish nonsense while running through the trans positions to check fluid other day.
Alt gets just as hot as the engine though too after a good drive.
Could be possible the new alt is faulty maybe
I don't always learn my lesson.
But when i do, it's the hard way.
Paul
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Posts: 91
Joined: Sun Oct 17, 2004 8:14 am
Location: Columbus, Ohio

Re: MR2 Alternator Upgrade?

Post by Paul »

If your voltage is reaching 15v, it may be enough to trigger the charge lamp signal. I tried a new internal regulator on my faulty alternator, but the charge voltage remained high. It was also smoking hot while idling, so I did not run it long. The new regulator may have been bad, or could have been wiped out by a faulty diode in the rectifier assembly. I finally decide to purchase a remanufactured stock alternator, and all is good now.
Heres a link to some similar issues from a MR2 site:
https://www.mr2oc.com/threads/alternato ... em.427775/
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SinusoidalTendencies
Top Notch Member
Posts: 151
Joined: Thu Sep 06, 2018 12:06 pm
My tercel:: 87 4wd wagon

Re: MR2 Alternator Upgrade?

Post by SinusoidalTendencies »

Funny thing the fsm we got here doesn't show which pin is which on the plug.... Trying to figure out the pin layout for testing
I don't always learn my lesson.
But when i do, it's the hard way.
Paul
Advanced Member
Posts: 91
Joined: Sun Oct 17, 2004 8:14 am
Location: Columbus, Ohio

Re: MR2 Alternator Upgrade?

Post by Paul »

I think this is it, looking at the alternator with plug removed...
s-l1600.jpg
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