Originally Posted by
Os8472
There are severale reasons
Relay 1 is for the fuel pump, self explanatory really as the ecu only runs the fuel pump if the engine is turning so in the event of a crash and the engine stops fuel doesn't keep getting forced up the lines. ok I'll go with this one
Relay 2 is for the injector supply, normally emerald say this should go on the same relay as the coil pack on 4 cyclinder engines but since I'm going to be running a second set of injectors later on it made sense to split them.Can't see any logic in this, as the ECU only provides a path back to ground, having 2 sets of relays to 'split' the feeds to the injectors will achieve nothing. Like DR states, you're making trouble for yourself.
Relay 3 is for the coil and I'd prefer to have the maximum power potential for the coil pack to guarantee a strong spark.Utter Guff - If you want to introduce the potential for less power getting to your coil within a 12v system - stick a relay in the way - it makes no sense.
Relay 4 is for the boost control solenoid and idle control valve, these being together isn't a problem as neither will be in use at the same time, the emerald system calls for both to have an ignition live and it's easier adding another relay than chopping the OE loom more than it already has.Nonsense - you've chopped something to integrate the relay, and I guess the signal wire operating the relay is an ignition live?
Relay 5 is the ecu supply, as I mentioned before the ignition live that had been used before wasn't a very good one, it was the OE supply for the AEI module but the ECU requires a bit more juice than the AEI did and I did find the ECU was experincing a voltage drop off under heavy load and again emerald do surguest that older cars converted to run an ECU might require an additional relay.You can have that one
Yes more relays might be more complicated but if I have any problems it'll be easier to narrow down the problem as everything is seperate so instead of losing everything if a relay goes down I only loose 1 componante