could pcm reflash be causing low battery?

[arab pinnochio]

I don't know what's been causing my car's battery to perform so badly. The voltage reads 12.7 when I check it and the alt. reads 14.5 volts. I'm just fishing here....the problem started after I had the dealer reflash the pcm, so could there be something wrong with the power regulation?

 

[Aricjm15]

thats normal

 

[mspdfreak]

The stock battery is a piece of s***. If the weather gets anywhere colse to cold the car barely starts. Oh well, time for an Optima.

 

[jersey_emt]

thats normal

Yup

 

[arab pinnochio]

argh......

Guys, I know the voltages read normal......duh........my post is in regard to problems I am having that have not been solved. I'm not using a stock battery. I'm using a 640 marine cranking amps battery with a reserve capacity over 100, and yet I have starting problems. My question was whether the pcm is controlling my alt's output?

 

[boostisgood]

No. The ALT output is controlled internally. You will always see 14.x volts from the ALT and roughly 12.X at the batt. The MSP, and from what I understand all Pro's have bad wiring, thus problems with starting in anything close to freeazing.

 

[BlkZoomZoom]

Actually yes, the pcm does control the charging output of the altenator. It uses several inputs to decide what charging voltage the alt. should put out. If you have a problem with the car, bring it to a dealer. The re-flash shouldn't change those parameters of the programming.

 

[arab pinnochio]

....

blkzoomzoom, what would the limitations of the pcm be in a mazda? the a/c, the alt....? That's the only change I have made to the car. Other than the reflash nothing is different. At first the dealership suggested it was the aftermarket stereo causing probs but I havent used the stereo for a long long time. There are no draws on the battery, so I'm wondering what could cause it to not charge properly? The ground wire is pretty solid, though the stock wire size isn't that large.

 

[BlkZoomZoom]

I'm not exactly sure what the question is. Are you saying you replaced the alt. and a/c? If they claim it is the aftermarket radio, I would try removing it and see what happens. Just because something isn't turned on doesn't mean it can't draw power.

 

[jurgs01]

He is saying that he has only done the reflash. First, did you wire up an aftermarket stereo? Second, take your negative connection off your battery. Check to make sure all of your connections to both your positive and negative terminals are tight. Are your battery terminals corroded? If so, get some good ones. If you are still having problems you can get a a circle earth grounding kit or the one 1sty makes. You can rule out the reflash causing it that doesn't make sense.