Fitting Megasquirt with EDIS to my MGB. Pure headache isn't the word.
My MG has 4 fuses for the entire car, that's it, so I've decided to start again from scratch. Marki has very kindly provided me with wiring diagram to sort most of the car out, and I think I've got the engine wiring sorted in my head.
Thing is, what is the 'Main Relay' and 'Fidle Relay' shown in some of the MS diagrams? I'm even more confused as the diagram Marki sent me appears to have 2 main relays; 70amp and 100amp.
Also, anyopne know how to figure how powerful my alternator needs to be? I currently ahve the standard SD1 fitted but that ain't gonna eb enough for EFI, two fuel pumps etc etc?
Main Relay and Fidle Relay
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The two main relays in my drawing are for the main key all the way round position and the ACC first click position of the key. The ACC one (70A) is for stuff like CD and amps, basically anything you want to run without having to have the engine running. The larger all the way round is for everything else i.e ignition, EFI, main lights. There is also a third which is key out which still has power to clocks, side lights and that, stuff that must have voltage all the time. This doesnt have a relay as its never switched. None of the relays in my diagram have anything to do with MS, they are separate again.
Alternator you would need to list all the stuff your going to run for anybody to be able to work it out.
Alternator you would need to list all the stuff your going to run for anybody to be able to work it out.
[Injectors 10A
ECU 4A If your using fiddle
Wideband 5A
Fuel pump 10A Maybe 15A your using 2 pumps] Taken from MS manual
Ignition 10A
Kenlow 10-25A (depends on size)
Water pump No idea
Lights Say 15A all in unless you use high watt lamps
Maybe another 5A for gauges and stuff, a little high but reasonable figure
All in you have a max of around 90A Except for your water pump. You wont run at this for most of the time as these are max figures. For example you could possibly ignore the fan but if you spend a lot of time in traffic at night (lights on) with it running then that's not a good idea. Think Its a lot? Well not really and this is why modern fuel injected cars run 100A alternators or larger. I think your probably looking at a 100A alternator too or look to reducing your electrical usage. Use a mechanical water pump, only use one fuel pump, stuff like that.
ECU 4A If your using fiddle
Wideband 5A
Fuel pump 10A Maybe 15A your using 2 pumps] Taken from MS manual
Ignition 10A
Kenlow 10-25A (depends on size)
Water pump No idea
Lights Say 15A all in unless you use high watt lamps
Maybe another 5A for gauges and stuff, a little high but reasonable figure
All in you have a max of around 90A Except for your water pump. You wont run at this for most of the time as these are max figures. For example you could possibly ignore the fan but if you spend a lot of time in traffic at night (lights on) with it running then that's not a good idea. Think Its a lot? Well not really and this is why modern fuel injected cars run 100A alternators or larger. I think your probably looking at a 100A alternator too or look to reducing your electrical usage. Use a mechanical water pump, only use one fuel pump, stuff like that.
