new battery, regulator, or alternator?

[orly_andico]

i'm having great difficulties starting my mazda 626. i noticed that after a night in the garage, my battery voltage is very low, 10.6 volts. this is the voltage of a fully-discharged battery, according to things i've read.

once the car has started, voltage across the posts is about 13.8 volts. i am concerned that this is a bit too low -- things i've read say it should be 14 volts. also, when idling, full aircon, full headlights, and stereo, the stereo drops out periodically (namamatay-matay). and the voltage across the posts drops to 12.5 volts or thereabouts.

i left the battery disconnected for a night, and its voltage went down from 12.65 volts to 10.6 volts, so it seems the battery cannot hold a charge anymore. however, i don't want to replace it right away because i think the alternator is not charging it fully, and a new battery might just get damaged after a month or two (the fact my stereo drops out means not enough juice is getting to it).

is there a way to adjust the regulator? maybe it is not providing enough field voltage to the alternator, so the alternator can't keep the voltage up at 14 volts. or could it be, the battery is so weak that the alternator's output is affected?

p.s. i have verified that the battery is not discharging overnight through some short or something (i put an ammeter in series with the battery), so it's not some dumb thing like the trunk light or dome light being stuck on..

[OTEP]

May free check up naman ng alternator in most battery centers (i.e. along Quezon Ave.). That way they can isolate if you have a battery or charging system problem.

In most old school cars, taking the battery off with the engine running was a way to check the charging system. Kapag hindi namatay agad, then the alternator is supplying enough juice.

[orly_andico]

ahh ok. motolite told me if i availed of their "home service" they would check the battery out but still charge me 300 if the battery turned out not to be the problem.

re: old school: i thought of doing that, but this isn't THAT old school, EFI na po siya. :P the battery daw helps regulate the output of the alternator, so removing the battery while the engine is running is a Bad Idea (TM). i don't wanna fry my ECU.

thanks though, i will call motolite again.

[antoy]

I think the battery is at fault. Have it checked to be sure

[kinyo]

a good battery will not drop to 10.6 volts overnight ... 13.8 volts is the normal voltage during charging (14 volts isn't that bad either) ... its a bad battery and alternator is ok ... how old is your battery, orly?

the regulator is an integrated circuit and there are no adjustments for it

[orly_andico]

re: battery age: i have no idea. :P i bought the car used with no service records not long ago (which is why i'm discovering soooo many things wrong with it, thankfully, none of them significantly impair the car's function).

i guess i better call the motolite hotline now. maybe the battery is less than 15 months old and they'll warranty it..

[OTEP]

If you don't have the warranty card, then you can't do a warranty claim for it.

[x-wind]

try mo na lang pumunta kung saan masmalapit na motolite shop dun libre ang service .........yun sa akin dun ko dinala sa tramo pagbaba ng flyover from edsa. naka off un engine then may equipment sila to chech kung how many volts and amp. ang down nya pag may load..............yun bossing dun advise sa akin na refil lang yun water free din sa kanila. dun ko rin nalaman na kahit free maintenance yun batery pwede refil ng water.

[x-wind]

try mo na lang pumunta kung saan masmalapit na motolite shop dun libre ang service .........yun sa akin dun ko dinala sa tramo pagbaba ng flyover from edsa. naka off un engine then may equipment sila to chech kung how many volts and amp. ang down nya pag may load..............yun bossing dun advise sa akin na refil lang yun water free din sa kanila. dun ko rin nalaman na kahit free maintenance yun batery pwede refil ng water............... hehehe muntik na ko nagpalit kasi nasa min. level na yun water yun pala pwede refil...............

[rodcarolino]

pwede tangalin ang battery habang umaandar ang efi engine as long na naka-idle lang and the positive terminal must not touch any ground/part of the body. kung sakaling na-rev mo na tangal ang battery siguradong dead ang computer box mo...

[chick-boy]

Originally posted by orly_andico
i'm having great difficulties starting my mazda 626. i noticed that after a night in the garage, my battery voltage is very low, 10.6 volts. this is the voltage of a fully-discharged battery, according to things i've read.

once the car has started, voltage across the posts is about 13.8 volts. i am concerned that this is a bit too low -- things i've read say it should be 14 volts. also, when idling, full aircon, full headlights, and stereo, the stereo drops out periodically (namamatay-matay). and the voltage across the posts drops to 12.5 volts or thereabouts.

i left the battery disconnected for a night, and its voltage went down from 12.65 volts to 10.6 volts, so it seems the battery cannot hold a charge anymore. however, i don't want to replace it right away because i think the alternator is not charging it fully, and a new battery might just get damaged after a month or two (the fact my stereo drops out means not enough juice is getting to it).

is there a way to adjust the regulator? maybe it is not providing enough field voltage to the alternator, so the alternator can't keep the voltage up at 14 volts. or could it be, the battery is so weak that the alternator's output is affected?

p.s. i have verified that the battery is not discharging overnight through some short or something (i put an ammeter in series with the battery), so it's not some dumb thing like the trunk light or dome light being stuck on..

ganyan din ang problema ng ride ko... except na hindi namamatay ang battery ko overnight. but all the signs that you are experiencing ay ganyan din sa akin... i have tried everything and last option ko talaga is to replace my alternator with a higher rating

[fierari]

battery lang yan.

[orly_andico]

just had the battery replaced.. and gads! it had problems starting AGAIN. was beginning to wonder if it's the coil pack (electrical problem). left it on for a minute, and it startedright up. my theory was fuel pump wasn't bringing enough fuel in. don't know if that theory is correct. will see next time it misbehaves..

[OTEP]

Ok ba voltage? Baka naman yung ground strap ng batter ang problem.

[orly_andico]

ummmm... the battery guy found issue with the fact that the charging voltage NEVER exceeds 13.8V even when revving the engine. so, the alternator seems to be working at regulating its output, pero it outputs too low a voltage.

am thinking of putting a diode in series with the alternator sense input so that the output voltage will be raised by 0.7V.

regarding battery strap.. yes manipis yung ground strap, it's gauge 8 stranded. nasindak yung friends ko sa kanipisan niya. but guess what.. that is Mazda's recommended wire size..

dagdag pa pala: the starting problem now is not that the engine does not crank. it does crank, and it cranks robustly. pero it doesn't catch. that's why i suspected ignition problem. but now i suspect fuel pump.. wear item naman talaga ang fuel pump on this car..

there's this "wonderful" Ford Probe/Mazda 626/MX6 FAQ at http://homepage.ntlworld.com/dorothy.bradbury/probemx/ which documents all the "wonderful" unreliabilities of the mazda 626.. dun ko nakuha mga info ko. actually frankly naniniwala ako na sakitin ang Mazda! kahit sa US forums they say the same thing.. buti nalang di matic car ko.. the 93-97 mazda 626 matic, laging namamatay yung tranny..

so i wanna check the fuel pump when i have money again *hikbi* kasi baka worn out na yung impeller. it could also be causing the palya at high RPMs problem..

[kinyo]

you have not mentioned it yet ... pero kumusta ang spark plugs mo, orly?

i think you are on the right track ... ignition system or fuel system ... by the time you have solved the problem, marami ka nang natutunan sa kotse mo

set aside your diode trick for the moment because 13.8 volts is not causing the hard-start problem ... raising 0.7 volts would give you 14.5 volts which can be detrimental to your battery bordering on overcharging

[orly_andico]

someone on the mazda 626 uk mailing list is telling me voltage on turnover (no load) should be 14.2V, and that there is something wrong with my alternator, and that i should buy a new/recon one.. oh well..

regarding starting: it seems na OK siya if left on for 30 seconds to 1 minute before starting. i can hear the fuel pump starting up and so far hindi na nagloko.. under observation for now.

(spark plugs are new, part of my last pms)