My P5 starts weak sometimes - just got new battery - what's wrong with it?

[Hank3]

About a month ago, my P5 wouldn't start. The Costco/Kirkland battery that the previous owner purchased pooped out. I switched out the battery with a 3-year one from Walmart and it's been fine, but this week I've noticed a few starts where the car is kinda weak. Not like it won't start, but when it starts the engine doesn't have that initial vrrrrooooom. Sorry for my noob description on what I perceive this issue to be, but any idea what this might be? Is the starter going out on me? P5 has about 95K on it.

 

[MazdaSpeeder]

Are the cable ends totally free of corrosion? (even look under the outer coverings) I had an issue like that and it turned out I had corrosion that I couldn't see that was causing this issue. i would start there. Soak the cable ends in a water/baking soda mixture until they no longer make bubbles, scrub with an old tooth brush, apply some of that terminal anti-corrosion gel and go from there.

 

[Hank3]

Are the cable ends totally free of corrosion? (even look under the outer coverings) I had an issue like that and it turned out I had corrosion that I couldn't see that was causing this issue. i would start there. Soak the cable ends in a water/baking soda mixture until they no longer make bubbles, scrub with an old tooth brush, apply some of that terminal anti-corrosion gel and go from there.

I like free and easy troubleshooting ideas. Thanks!

 

[wolleymp5]

Could be the alternator is not charging the battery. Take it to autozone or autoparts and have them do the alternator test, its free and they print out a small report which says if the alternator is working correctly. Have them check the battery as well to make sure there is no damage to the cells. If there is then you can replace it and put a new one once the alternator is changed (if that's the fix).

When a battery dies, since the alternator is trying to charge it but the battery will not charge it creates a "back current" to the alternator creating a short circuit. That's why its not a good idea to jump start cars too many times because of the short circuit to the alternator and possible electrical system damage and ECU implications. I've done that with an mx-6 and killed a year old alternator.

Clean the connectors like said, and get some dielectric grease to ensure good connection and prevent corrosion.

good luck.

 

[exalted_one]

Could be the alternator is not charging the battery. Take it to autozone or autoparts and have them do the alternator test, its free and they print out a small report which says if the alternator is working correctly. Have them check the battery as well to make sure there is no damage to the cells. If there is then you can replace it and put a new one once the alternator is changed (if that's the fix).

When a battery dies, since the alternator is trying to charge it but the battery will not charge it creates a "back current" to the alternator creating a short circuit. That's why its not a good idea to jump start cars too many times because of the short circuit to the alternator and possible electrical system damage and ECU implications. I've done that with an mx-6 and killed a year old alternator.

Clean the connectors like said, and get some dielectric grease to ensure good connection and prevent corrosion.

good luck.

I think those alternator/battery testers are a sham. Between my family we have gotten so much misinformation from them. Alternators reported to be bad when they were good, and batteries reported to be good when they were bad. I don't know if is operator error or shoddy machines but either way I don't trust them.

 

[us3r]

I have same problem as well. 1 year old kirkland battery doesn't hold a charge. I don't think it's the alternator because the battery light is not on. I get a reading of 14.xx when car is running. Maybe there is a short somewhere or the wires need replacing?

 

[MazdaSpeeder]

The problem with getting the alternator tested is that it's kindof a pain to pull. I would run down the easy stuff first.

 

[P-Funk!]

No CELlight?
14VDC on the battery?
-probably bad cables. Replace them.

 

[wallabe]

Also it could be a bad battery, Wal-Mart is known for re-selling batteries people bring back if not needed.

Get the alternator and battery tested

Still check all connections and wires, replace what is needed by cheapest order first.

Check fuses first, wires, then check the parts

Good luck

 

[tweety2300]

Do a volt test on the starter. You may have a cracked wire in there, not likely but I've had this issue with 2 mazdas so far

 

[KCKrogoth]

Put a meter to it, a multi-meter is your best friend for electrical Trouble shooting:

- Battery with the car off should be around 11-12V ish just sitting...If lower than that by much prob a bad battery
- Battery with the car running should be around 13-14V ish with accessories off (AC, Radio, headlights, etc. anything causing a large draw on power)...if it's too much lower than around 12.5 prob not getting a good charge from the alternator, could be the Alt itself or cables.
- Put a meter on the battery and have someone start the car, if the volts drop down real low, to like 4-8V or so, then the starter is going out...it's drawing too much power because it's struggling to start the car. Had this happen to me personally, started my car with a brand new Optima Yellow top and the car wouldn't start for crap, put a meter on it, and was drawing down to 5V on the pull, pulled the starter, took it apart, was burnt out, replaced it with a new one...works like a champ now!

 

[P-Funk!]

Is it still slow to start (low crank speed - not time to start, right?) after already running/warmed up? Could be a starter starting to fail or corrosion on the cables...
Or only first start of the day (sitting a long time)? Could be a short is drawing it down overnight...

 

[Hank3]

It's not really slow to start. Just that when you start it, it almost seems to immediately go to a quiet idle instead of having the engine go "vrooooom." It's happened after the car has been sitting for a few hours.

 

[tweety2300]

So it's starting like its supposed to?

 

[Hank3]

Yup

 

[KCKrogoth]

I'm confused now, sounds like there isn't a problem... (uhm)

 

[Hank3]

That's what I'm trying to find out...if this is a problem or if it's normal. Car starts quiet after sitting for an extended amount of time.

 

[KCKrogoth]

Doesn't seem like a problem to me, as long as it starts and isn't struggling to start or anything like that.

 

[bazooka joe]

if it starts and has no drivablity issues, then no worries!

 

[P-Funk!]

[smacks forehead]