3 replies to this topic

[Muda]

My '99 is charging at 16.5 volts.
I've done the following so far:

1. Changed alternator (correct part), no change.
2. Changed ECU, no change.
3. Checked grounds and connectors. Checked for shorts and excessive current draw. Everything looked OK.

I understand that the voltage regulation is shared between the alternator and the ECU. I read that there is also some voltage control in the dash pod. As my car has had the dash pod removed could this be the source of the problem? Tomorrow I will check the continuity of the harness between the alternator and the ecu as this is the last area I can think of that could be causing the problem.

If the regulator circuitry in the ecu was bad would it have damaged the circuitry in the alternator when I replaced it?
Is it easier to just add an external voltage regulator? Does anyone have the wiring diagram for this?

[Jim Drago]

Did you buy an Autozone or some other crappy rebuilt alt? If so, buy a good one and try. I gave up on rebuilts other than a local guy I use here or I buy factory remanned from World pac. If not swap the ECU and see if that fixes it. It is one or the other. If you don't have a spare ECU, I can send you one to test.. Just don't tell anyone, they may start to get the wrong impression

Jim

[Bench Racer]

I can send you one to test.. Just don't tell anyone, they may start to get the wrong impression
Jim

My spacer that fits between the steering wheel & seat is approx 5 foot 4 inch & 165 pounds. Could you locate the seat accordingly & re-set the car. I'll trailer on down to pick it up.

[Muda]

My replacement alternator is a rebuilt Mazdaspeed unit. Checked harness continuity to the ECU, perfect. Cleaned alt. connector. Tested two ECU's and two alt's. Both charge at 16.5 at battery, 16.75 at alt. pole.

How can I test the regulator circuits on the alternator and ECU?