Car Alternator or Battery Issue

^pomen_GTR^

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Dear All,

I have a car with 1JZ VVTI engine having consistent battery die on me issue. Symptoms i've detected so far:

1.) Power windows auto mode not working, unless i rev the engine to 2000 rpm
2.) Power windows roll up too damn slow
3.) Idling seems very low and at the point of stalling, when the rev gets about 400 rpm, the battery light turned on
4.) Lights were dimming but it was fixed after i replaced with a new battery (2 weeks old)

The alternator was fixed a week after replacing with a new battery, by replacing the carbon brushes due to its age. The engine starts and runs fine, however the power windows are still working slow. Idling still pretty lousy, at 650 rpm at cold start, but runs fine after warmed up.

One fine day, the battery died on me again, but partly due to the car is in a garage under going cosmetic repairs, the repair guy accidentally left the car lights on overnight. The next day we jump started the car but i doubt the battery is properly charged.

So far our test results as below:

Battery voltage while engine is off: 11.8 v (mechanic commented it is low, as it should be in between 12.2 - 12.5)

Battery voltage after engine started with no accessories on (radio, lights, A/C): 13.5v (mechanic thought it looks ok)

Battery voltage with accessories on (radio, lights, A.C): 13.8v (mechanic said it looks ok)

Honestly i think the alternator still do not produce enough charge or i am just being paranoid.

What are the chances i need to replace the whole alternator unit ?

Thanks,
Ken

obviously after alternator repair the charging is fine...

your battery if new (and just only accidentally drained once) should be fine...


as your idle speed, its tuning issue...

and slow moving power window...is electrical issue..like grounding/wiring is old and worn
 
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Mitevo7

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obviously after alternator repair the charging is fine...

your battery if new (and just only accidentally drained once) should be fine...


as your idle speed, its tuning issue...

and slow moving power window...is electrical issue..like grounding/wiring is old and worn
As for idle speed, since mine is a converted E46 that still uses old 318ci tachnometer, i think the readings will not be 100% accurate. My best guesstimation, when 650 rpm on the tacho, i should have around 700 rpm. The tuner said he can't do it any higher, or else the engine itself will rev itself to 2000 rpm when we apply and release the throttle before going back to below 1k rpm.

Another findings, when the cooling fan kicked in, the voltage will drop from 13.3 v to 12.7 v, the reading was taken when the car is stationary, to simulate traffic jammes or other bumper to bumper traffic.

Slow moving power window, i might want to look into the railings. Might just dirty tracks, cause all the groundings are revamped.

Thanks,
Ken
 

^pomen_GTR^

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Another findings, when the cooling fan kicked in, the voltage will drop from 13.3 v to 12.7 v, the reading was taken when the car is stationary, to simulate traffic jammes or other bumper to bumper traffic.

if u got like functional obd2 to display (or verify) actual engine rpm...the idle rpm should need no worry...

but if voltage drop from 13.3 to 12.7 (consistently dropping below 13v),
do same test... now with ac on, and full headlights on as well on idle.... to see if there is idle compensation during load or not... (not sure if jz have that function or the ecu function) and see if the voltage drop further means alternator amperage not sufficient...


your radiator fan use jz fan or bm fan?
 

vr2turbo

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Yup, agree with bro. pomen. If voltage drop below 13v then you battery not enough charge already.....
 

Mitevo7

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if u got like functional obd2 to display (or verify) actual engine rpm...the idle rpm should need no worry...

but if voltage drop from 13.3 to 12.7 (consistently dropping below 13v),
do same test... now with ac on, and full headlights on as well on idle.... to see if there is idle compensation during load or not... (not sure if jz have that function or the ecu function) and see if the voltage drop further means alternator amperage not sufficient...


your radiator fan use jz fan or bm fan?
I am using BMW fan from M43B19, its supposed to be high speed fan. The voltage dropped to 12.7 when the fan is spinning very fast for few seconds, and voltage recover back to 13.3 - 13.4 v after it slow down.

Thanks,
Ken
 
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Mitevo7

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Yup, agree with bro. pomen. If voltage drop below 13v then you battery not enough charge already.....
Hi,

The drop is momentary and recover back to 13.3-13.4, this was taken only during idling. I am not 1JZ ECU is OB2 compliant or not, but can we actually tune up the idling RPM so that the idling charge is enough?

Thanks,
Ken
 

Mitevo7

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dual speed fan?
From the sound of it when its activated, it looks like a dual speed fan. I remembered there was a year when the original cooling fan will constantly tuned into highspeed mode (real loud from the outside when its spinning very quick) and slow down to normal fan speed after engine reached warm up temperature, in the end we found out the fan switch is faulty and constantly putting the fan into highspeed mode. That burned out the motor pretty quick.

Thanks,
Ken
 

Mitevo7

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Folks,

I have been seeing online and found there's alternator voltage booster module available for certain type of cars. Wondering is there such devices in Malaysia to help with my current issue ?

Thanks,
Ken
 

Izso

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Folks,

I have been seeing online and found there's alternator voltage booster module available for certain type of cars. Wondering is there such devices in Malaysia to help with my current issue ?

Thanks,
Ken
Which booster you read up about?
 

Mitevo7

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Ah... I would not use those things.

I like this guys videos, might help you :
Alternator returned fine, only at low rpm the charging seems inadequate. Besides increasing the RPM (which is out at this moment), i ran out of option to try to increase the voltage output, earth cables are fine and can't seems there's much resistance in the system. Hence comes to this booster module.

Thanks,
Ken
 

gunnerzz

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Did u check or is there any way to check the alternator output at the source meaning at the alternator itself.

After reading this all over again i think there is a bad connection somewhere.
 

vr2turbo

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Did u check or is there any way to check the alternator output at the source meaning at the alternator itself.

After reading this all over again i think there is a bad connection somewhere.
But the charge is fine with accessories off, pass 14v....
 

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