Emerald advice

Hi guys,

Got my hands on a second hand emerald this week so have been busy wiring it up the past couple of nights. All i have left to do is connect up the fuel pump/injector relay wiring. I’ve seen Phil’s website which suggests installing a new relay - how do i go about connecting it up so that i retain the original relay?

Im left with a purple wire (+12v unswitched) and an orange and purple wire (switched earth pin 20 ecu). I can wire these up to the relay but surely this will result in no inertia switch present in the system??

Any help would be mucho appreciated as im an electrical numpty!! Oh an my bloody back is now in agony!!



Just use the relay to switch the existing one on.

Take the orange/violet wire (from the existing relay) and attach it to the output of the switch, connect the violet +12 to the input of the switch and coil, use the wire from pin 20 of the Emerald to the other side of the coil.

The inertia switch will still work, i know coz i forgot to reconnect it and wondered why it wouldn’t start

I told you, just call Emerald asking them to fax you a copy of their Exige wirinf diagram…

Thanks Phil i see now why you have an extra relay. Spent ages last night trying to figure out how to wire up the existing relay so that i retained the inertia switch.

Oh well of to halfords at lunch time to pick up another relay.

PS. You list two wires as chassis ground (no 7 & 67) - where did you ground these out? I guess these are no longer connected to anything so cant i just cut these and insulate?



I tell you, you don’t need another relay.
It is well explained in the wiring diagram for the Exige that came with the ECU, I would pass you the details, but I lost the page.

So do yourself a favour, avoid adding another electrical piece that might go wrong and call Emerald for the page.

It was just a case of swapping two wires on the existing relay…

Uldis - i got a wiring diagram from them but i dont think its exige specific. Its titled ‘typical crank trigger based system’.

I guess you got a different diagram?

Specific for the Exige. They have it.

Ok ill ask them again.

Hope they dont mind helping me out too much seeing as i havent really spent any money with them yet.

Nope, they know you’ll be in for a remap sometime…

Yep can confirm, if they can’t help email me and I’ll dig out my Emerald docs and scan them in for you

There’s a way of splicing 2 wires together (IIRC it’s a white one and yellow one)… But use solder as I didn’t first time then woindered why the fuel pump wouldn’t arm

do the connectors just pop out of the existing relay housing to swap about then ?

I never looked when i did mine as an Emerald Exige wiring diagram never existed !!

Hmmm, don’t remember if it was just swapping or splicing. Maybe a bit of both.
But it had to do with the fact that it is normally a “ground to switch” or “12V to swich”.
Just had to do the opposite.

And if I remember well I added a wire from a leg of another relay and spliced it to one of them.

Something along those lines.

Okey dokey, the Exige Emerald Wiring Diag


It’s high res so about 2.5 MB… I’ll compress it a little later but gotta go now…


not working Mark, all i got was 80K and not a pdf file

Yep, file is corrupted, brings the message:

There was an error opening this document. File does not begin with ‘%PDF-’.

Upload again?

Yep, file is corrupted, brings the message:

There was an error opening this document. File does not begin with ‘%PDF-’.

Upload again?

same for me Remarky boy…

OK folks all working (stinking FTP! LOL!), low res now so only about .5MB

That’s it, that’s the one!


cheers for posting the diagram. I know this set up will work but surely it does away with the inertia switch? Going by the ‘fuel pump and coil’ wiring diagram in the lotus manual, the yellow/purple wire grounds to earth through the inertia switch so cutting it will just take it out of the system.

The setup Phil uses with an extra relay keeps the inertia switch active.

Correct me if im wrong as i my electrical skills consist of burning my fingers with the soldering iron!!


Hmmm, I see what you mean, but if I remember correctly i didn’t exclude any part of the system.
Maybe I didn’t cut the wire?
All I needed was 12V.

Call Emerald (I would, hell, I did call them about 4 times during the time I did it)