Alternator issues....I think? Just bought a Protege

[Wy2sl0]

Hi everyone. I am getting idle voltages between 12.2-13.0. Once I accelerate or am in motion it will run between 13.6-14.0 without any load. Battery is in good condition (holds 12.5 or so with car off and aftermarket amplifier on). The alternator is also making a noise which I traced with a stethoscope. I am looking at getting the maniac motors 140 amp version, however I am unaware of the proper operation to replace the alternator. I extensively searched and saw a lot of threads on the 1.8 but I have a 1.6 (1999 protege). Any tips would be grateful as I do not have a lot of money to pay a mechanic. Thanks,

Matthew

 

[concept]

How does it start? If it starts quickly, what is worrying you?

 

[firelizard]

Replacing alternator is pretty easy. Remove belts (power steering pump and alternator are the 'tensioners' for their respective belts), then undo the bolts holding the alternator to the block and adjustment bracket.

 

[Wy2sl0]

OK so I replaced the alternator, but I am still getting low voltages. The alternator company is thinking there may be some wire shorting out, or a bad relay of some sort. I am going to try changing the battery to see if that is the issue, but I am really at a loss. With just the A/C on at idle I am now getting 12.0-12.4v with a 140 amp alternator, so there is definetly a problem somewhere.

 

[concept]

Wait, didn't you have the old alternator checked at the auto supply store? Always have them test the alternator before replacing it. The same applies to a suspected bad battery - have it load-tested BEFORE swapping it out for a new one.
It could be a wiring issue (wire or connector pin partially disconnected) to the alternator or a ground cable that is not making good contact.

 

[Wy2sl0]

I upgraded the grounds to 4 awg and scraped to bare metal. Also fused a new 4 awg wire from the alternator to the battery. The old alternator had a bad bearing and was screaming anyways so it was due for replacement. What kind of wires/pins should I be looking for? The grounds as I said are solid.

 

[concept]

Any alternator connector pins if there are any, should be checked. It is possible that the battery is not accepting the charge and you can test the alternator while it is running to see what its output voltage is. Do you have a service manual? I have an electronic one and can check the alternator testing procedure if you don't have one, yourself. That would rule out the alternator as the culprit and since you replaced the wiring, most likely, that is not the problem, either. I would first take the battery in to have it load-tested. That way, if it fails, your problem is most likely, solved.

 

[Wy2sl0]

Ok so...Battery without accessories on when off is 12.7v, so it is strong. When I am above 1k rpm, car stays around 13.6-13.8v. Fact of the matter is I thought an HO alt with double the amperage wouldnt drop that low from the fans and AC being on at idle.....really disappointed.

 

[concept]

I think that is within the normal range.