1jzgte alternator overcharging, changed regs...still doin it?

[IN 05 NT]

ok, so the wiring saga in the mx23 is on going,

the alternator is now overcharging at 14.7v average,....we've swapped regs from another 1jz alternator and it has made no difference,

it was originally charging at 14.2ish volts...now it has spiked to the 14.7v?

anything else that could be causing this?..........

part numbers the same but other numbers dont match?....top is the old reg, bottom is the new reg that i fitted,.........

[TurboRA28]

Checked the wiring to ensure everything is connected as it should be? Maybe the S wire not getting correct voltage from battery?

[maurice c]

Check that the body of the alternator is earthing to the engine block.

[IN 05 NT]

Because the battery is in the boot we ran a wire from sense right to the battery positive terminal. Still the same. Insteresting to note that when disconnected it reads 14.3v

Alternator is bolted and earthed to the engine block

[celicapain]

Maybe voltage loss on the S+ line running to the battery? If your running very thick cable to the battery youll have more resistance in the S+ wire than the battery cable which should push your alternators voltage up a bit-Try connecting it closer to the alternator to see if that fixes it. I would have thought that with the S+ wire disconnected it would push the voltage as high as it can go but obviously not.

[The Real Roadrunner]

http://www.autoshop101.com/forms/h8.pdf

witzl posted it in faq.

as stated earlier, i hate electrical stuff

[thechuckster]

is the sense wire you've run to the battery going thru any switches?

when discussing this sort of issue with Wilbo, he said that the sense wire doesn't need to be large,

how are you connecting the battery (-) to the chassis and engine? relying on mount tabs connected to the shell will cause you problems.

[wilbo666]

The autoshop document is good

Also page 13 of the autoshop document (The trouble shooting section) says "Is battery voltage 14.5V +- 0.6V when regulator temp is above 80deg F (26.7Deg C) voltage range is 13.0 to 15.5V.


Sounds to me that it is within range?...


This post also gives some background on the sense wire (what thechuster is talking about)
http://www.toymods.net/forums/showpo...1&postcount=27


As thechuckster says, how do you have it wired up?

Cheers
Wilbo

[IN 05 NT]

Brad has wired it thru the body loom of the car, so its running the plug from the old external reg,......as it should, the charge light is working on the dash....., the main feed from the battery runs to this terminal \/\/\/\/ mounted in the egine bay wher the starter wire, and alternator main wire connect to the main middle post, while all the relays, body loom,/water pump and a few small things run off the srews around the base,




we disconected the battery in the book and hooked it up to the car with jumper cables in the engine bay, and its still the same 14.7V........theres no voltage drop to the boot of the car.....we also used a different battery.....to see if it were trying to charage it as hard......weve left the car idle for a few minutes also, as to see if the chatge rate drops after the initial star up...........its stays at a constant 14.7.....

id leave it at that charge rate, but i believe (i hate elektrizity) that the higher charge rate is causing the fuse in my electric water pump controller to blow after about 20mins of driving, ?.........the wire seems to get warm over a period, ,then blows, but the wire also spikes hot/then cold......waiting to call davies craig on monday to see if theyve had similar issues....

[thechuckster]

using the chassis loom for the charge light is OK - but the sense wire should be a single cable running from alternator straight to the battery - not the distribution post.

just runs a temporary (and light) cable from alt - S pin to the battery and see if you get a change in charging - it would at least eliminate any chassis loom related issues.

[wilbo666]

just runs a temporary (and light) cable from alt -L pin to the battery and see if you get a change in charging - it would at least eliminate any chassis loom related issues.

You mean Alt S right?

Cheers
Wilbo

[thechuckster]

yup - am glad someone was reading

[stidnam]

using the chassis loom for the charge light is OK - but the sense wire should be a single cable running from alternator straight to the battery - not the distribution post.

just runs a temporary (and light) cable from alt - S pin to the battery and see if you get a change in charging - it would at least eliminate any chassis loom related issues.

We gave that a go last night. Disconnected the sense wire from the body loom and connected it straight to the battery. Didn't see a drop in voltage. Would the length of the sense wire/distance of battery make any difference?

stidnam

[oldcorollas]

where are you measuring the voltage from?
put jumper lead from body of al to engine or to car body?

is there loss on the ground path from engine to battery? checked resistance?
body of car is not always so good at passing 40-50amps continuously thru it

[IN 05 NT]

havent checked resistance, but checking voltage by earthing it to the body, and the positive junction block in the eng bay, its got the same charge rate at the rear of the car on the pos and neg terminals on the battery aswell tho......,

i think i'll try another alternator all together and see if that makes any difference........