I'm putting a '05 AP2 engine/trans into a 1964 Triumph TR4 (it fits fine,thank you). I'm using an Urge design head and ITB set-up and I'll be using an Emerald ECU (you may not have heard of them).

As I get along to wiring the the harness up, this question came up:

Can you tell me if the Alternator requires a signal from the ECU to turn it on? Or is it always on (at RPM)

Thanks,

Rod

 

 

I guess, this diagram shows the white green wire or the white red wire coming from the ECM as turning on the alternator, any way to find out what signal they are sending to the alternator?

 

This one looks a little better. But to answer your question, yes the ECU needs to talk to the ALT.

 

all you need to make it work is to supply the switched power .. see the diagram above. the black/yellow wire.

the ecu applys a signal to the alternator to turn it off, it defaults to on.

 

So what is the purpose of the ELD? Im curious. I was assuming it was some sort of electronic regulator for how much charge it puts out.

 

the eld tells the computer how much load there is on the electrical system, then the computer can use that info to turn off the alternator.

With aftermarket ecu's you dont need that.. aem doesnt do anything at all with the wires running from the alternator to the ecu.. in fact those pins are setup for egt inputs if i'm not mistaken.

 

Ah, thanks for shedding some light

 

Thanks gentlemen, this makes the task a whole lot easier.

Rod

 

I want more info/pics on the car!!