14 replies to this topic

[mitchg]

Hey guys,
Iv posted this question on some commodore forums but if its not about chrome wheels and no springs then they dont have a clue.

Iv replaced the battery, and alternator in my VX SS, but its still not charging the battery which is telling me its something to do with the connection from the alternator to the battery. Now I have had this image to study:



From this I can see, the white wire YE38 is my problem leading to the fusible link as this is sensing the batteries charge level and responding to the alternator.

To trace this on the car seems ridiculous as it runs under the engine and I havent been able to get it in the air to check it out from underneath, but is there anything I am missing that could be the problem?

What should i be looking for? Iv never seen a fusible link before and I dont know if I should be replacing the fusible link or replacing the whole wire from the battery to the alternator?

Anyone done this before to an LS1?

Cheers,
Mitch

[ls2lxhatch]

Does the alternator light come on when the ignition is switched on and does it go off when the engine is started?

[mitchg]

It is on all the time. Ill jump start the car and it sits at 12.0 volts, and slowly makes its way down to around 9V which it then dies and can not be started. The alternator was removed and tested again at the joint that recoed it.

[ls2lxhatch]

It is my understanding that the alternator light will switch off even if the charge wire to the battery is not connected. I would see if I could borrow an alternator that you know is working.

I can not remember where I got the following information from but it is what is used to setup the alternator in the Torana.

Alternator Description
The L-terminal circuit from the generator is a discrete circuit (a discrete circuit has no splices and only one source and destination) into the PCM. The PCM applies ignition voltage to the generator L-terminal circuit. A small amount of current flows from this circuit through the generator windings to ground to create a magnetic field which starts the generator process. When the generator is at operating speed and producing voltage, a solid state switch for the L-terminal circuit in the generator opens and the PCM detects that the initial startup current flow has stopped.

The PCM expects to detect low voltage on the L-terminal circuit prior to the generator rotating at operating speed and conversely expects the circuit to be at ignition voltage potential when the generator is operational. When the PCM detects a fault (circuit shorted to ground, or circuit shorted to voltage), the Driver Information Center will display Charging System Fault.

The generator has an input to the PCM called the F Terminal to indicate the percentage of total capacity that the generator is producing. This signal is detected by the PCM as a duty cycle from the generator and displayed on the scan tool as a percentage. The PCM can monitor the generators output under all conditions to determine if it is functioning normally.

When there is low demand from the electrical system on the generator, a low duty cycle percentage will be displayed. As more accessory load is placed on the generator, the duty cycle output detected by the PCM will approach 100 percent. A normally functioning generating system will never reach 100 percent as indicated on the scan tool.

L terminal is orange/red
F terminal is grey


Alternator ECU bypass for engine swap into Torana

L-Terminal Orange/Red.
Remove the orange wire (L-terminal circuit) from the ECU and wire it to the ignition switch and a globe on the dash. When you turn the key to on the globe will light. Once the alternator is working the switch in the alternator opens and the globe will switch off. If the alternator fails the light stays on.

F-Terminal Grey
This can be left connected to the ECU so the scan tool can read alternator load.
Alternatively it can be connected to +12v ignition

Edited by ls2lxhatch, 13 August 2012 - 10:27 PM.

[mitchg]

Well Id like to think Iv ruled out the possibility of it being the wire as testing the charge on the battery, its the same volts as I can read on the plug. So this would mean the wire is working as it should.

But now, I cant even start the bloody thing, just clicks once and nothing. Cant jumpstart it either.

Could this be an ignition relay or something?

Ill also say I relocated the PCM from the engine bay to the passenger kick panel, but this was a matter of undo, feed the wires through the firewall and reconnect.

It worked fine when I first started the car after replacing the alternator, and the PCM was moved. Thought all sweet, under no load, it was reading 14.1 volts, 13.8 with accessories. Packed up and left it, went back about 6 hours later to drive somewhere, and battery light was on from start up and was sitting at 11.7 odd volts until it just died. So.............. yeah... where to?

[ls2lxhatch]

The charge light on the dash could be controlled by the body control module. If it is then it is possible that even though the light is on there is no power at the L terminal so the alternator will not start producing power.

You could check that when the ignition is on engine off that you have power at the L terminal. If you have power at the L terminal then I am out of ideas.

It is odd that the battery drained over a couple of hours.

[mitchg]

Which relays am I checking lol

[mitchg]

All good ill check it now. Also, is it possible to short out the voltage regulator in an ls1 alternator? is there a possibility in all my shenanigans the nut on the back of it has grounded somehow and shorted out? Its just funny that it worked perfect the first time i fixed it and now no good.

[mitchg]

I'm at the point where I think I'm running in circles.... Could be the problem all along.

[mitchg]

Well i got shits, took the alternator out and gave it back to the auto eleccy to look over. Turns out it was a faulty voltage reg when they recoed it. Replaced under warranty and it now runs perfect! For now...... Lol