Replaced LQ1 alt, now something strange happens...

[crazyd]

I get a full charge from the alternator for the first three minutes or so, then if I put the car in reverse or step on the throttle even slightly, the alt stops charging and goes to battery voltage. Tried swapping to another (new) alternator, still the same thing. I've gone over all my wiring and I can't see anything wrong, the grounds on the front and rear of the bellhousing are tight and no wires are touching anything hot. Then it gets weirder. If I shut the car off then start it back up, it's fine again for another three minutes. All this was fine before the previous alt went out.

This is a '95 with a CS-130D.

[88GTRacer]

Did you test the battery and make sure it's fully charged?

[crazyd]

Can the battery really be to blame for this kind of behavior? My assumption would be that if the battery was too low, it wouldn't charge at all.

[pocket-rocket]

Have you checked the actual wire inside the jacket (insulation) on the battery cables? How old are they? Corrosion can creep down them inside the jacket.

My car wouldn't charge at high rpms because the previous owner didn't tighten the cable connection at the starter. The cable goes from the battery to the starter and then to the alternator, so I would check that connection too.

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[crazyd]

I don't think there's much to check on the cables, I doubt they could fail suddenly like this. I have just replaced the starter in the last feew months with the minitorque upgrade from the L67, and those wires are all tight. What else could it be? Why does it reset for three minutes if Ishut off the engine and restart it?

[Dave96z34]

Maybe you have a weak battery. I know its cold in WA this time of year was your battery dead and then the temp got below 32 and the cells fractured. Turns a battery in to a paper weight.

[crazyd]

A self-exciting regulator (D702SE) for the CS130D from alternatorparts.com finally solved the problem.