Alternator not charing correctly/voltage loss

[midnight_purple_GA70]

Well I have an ongoing issue with my car where i see voltages of around 13.2 while the car is running... when revved the volts dont generally rise either... yet the car will hold at 13v and the battery is a known good battery have also tried swapping for a known good working alternator with no extra volts seen...

the 2 places where volts are being checked are on my apexi turbo timer and on my microtech hand controller... both suggest a 13.2v reading... (will be checking voltage at the alternator tonight with a multimeter)

my car was a GA70 and has been swapped to a 1jz so the alternator moved from right next to the fuse box to down the bottom of the motor on the passenger side...

I cut and lengthened the 3 wire plug to extend around the front of the car to the new alternator location...

The main power wire i also joined to the existing power wire that enters the fuse box...

I suspect the later of the 2 is where my voltage/charging loss is taking place...

anyone else had any experience with this?

when the car is on it isnt running a big sound system as ive disconnected that it is running... all via relays...
2x thermo fans
fuel pump
microtech
gauges
and the standard functions of the car...

i cannot recall having the same voltage issues before converting to 1jz but it was years ago when i started this so i wouldnt honnestly be able to say if it did or not...

Any other ideas what i should check?

[JP]

Check for voltage drop between the alternator and battery post, I had a similar problem and ended up doing new grounds and having a new thicker main power cable made to run to the alt.

[midnight_purple_GA70]

Check for voltage drop between the alternator and battery post, I had a similar problem and ended up doing new grounds and having a new thicker main power cable made to run to the alt.

when you say you did new grounds... do you mean extra earth straps to the motor or just new grounds from the battery to the chassis?

the cable to the alternator is a 120amp 8gauge cable i believe... alternator fuse is 100amp so i would of thought this would be sufficient... will still test a few things tonight as i didnt bother playing with the car last night...

[MWP]

I have the same problem with a low running voltage of 13.0 to 13.5 volts.
Ill do some digging around today, and report what my problem was.

[JP]

I ran a new ground from the engine block to the chassis, and from the battery to the chassis

[midnight_purple_GA70]

ok sounds good...
also when i hold the up button on my passenger window switch the volts will rise up to about 13.8
and when i hold the down button they drop... however this could just be where the power source for the turbo timer is running from i assume... havent confirmed if the microtech shows the same voltage increases and decreases when i hold the window button just noticed it on the turbo timer...

[oldcorollas]

have you checked with a multimeter? mayeb those devices are not good at reporting accurate voltages?

[midnight_purple_GA70]

have you checked with a multimeter? mayeb those devices are not good at reporting accurate voltages?

yeah will be checking with a multimeter tonight...

From memory... when i had the twins on the car i think i used to have the same issue... checked voltage at the battery with multimeter and had the same low result...

im pretty sure when i had the 1ggte in there it ran on the turbo timer at 14v or so and acted normally... but this is going back quite a long way now...

will be checking voltage directly at the alternator tonight as i dont recall if i tested that before...

but the main thing that changed between the 1g to the 1j was lengthening the alternator wires so i suspect ill find that the join is where im experiencing the voltage loss... or at least thats what i hope...

[hemi twofifteen turbo]

There is a battery sense wire on the 3 pin plug. This is the input that the regulator uses to maintain approx 14.4 volts. Re route the sense wire to the junction you want to be at 14.4 volts and that should solve the problem as it will automatically account for voltage drop. If the sense is connected to the B+ on the back of the alternator then it will maintain the 14.4v at the alternator only and won't account for the voltage drop along the line when under load.

[midnight_purple_GA70]

There is a battery sense wire on the 3 pin plug. This is the input that the regulator uses to maintain approx 14.4 volts. Re route the sense wire to the junction you want to be at 14.4 volts and that should solve the problem as it will automatically account for voltage drop. If the sense is connected to the B+ on the back of the alternator then it will maintain the 14.4v at the alternator only and won't account for the voltage drop along the line when under load.

when you say re-route it to the junction i want to be at 14.4v which junction should this be? i would like the battery to be at 14.4v so would i connect it to the battery or somewhere in the fuse box...

this does however sound like it could fix my problem as volts seem to drop of a little when under load...

[hemi twofifteen turbo]

Direct to the battery would be best so you always know it's getting proper charge voltage. The wire only needs to be thin, but don't be surprised if the wire in the plug is thick (seen it like that on an ae82)

[midnight_purple_GA70]

thanks for the help. Seems to be working now until the car gets hot then i have the same issues... Thinking maybe the alternator is having issues itself

[midnight_purple_GA70]

so anyone have any ideas why ide lose voltage once the car warms up?
its kinda got me stumped a bit

[JP]

dodgey regulator? Increase in resistance in a wire as it gets hot?

[oldcorollas]

them.

does the alternator power wire go to the strater wire? or straight to the battery?