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Crescent205

Emerald wiring to fuel pump

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Crescent205

Forgive me if this has been covered before which i would think it has but a search hasn't come up with an answer for me. Basically i've taken my carbs off my mi16 and put some t/b's on along with a K3 emerald ecu, I've wired everything up and made a loom but i'm stuck on the switched earth output of the ecu for the fuel pump relay. Can i use the original tachometric relay or do i have to wire a completely new set up? I don't fancy running it on a switch like the car i took them off was!

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welshpug

doesn't the loom have relays on it?

 

 

typically you would have one relay triggered by your switched live which will power up the injectors coils and ecu, and a second one that the ecu triggers.

 

connect a fused permanent live to both, take a switched power for the fuel pump relay from the first for the switching side, then the ECU pulls that to earth.

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jackherer

Use a new standard automotive relay. The wire to the fuel pump is accessible on the brown multiplug under the dash on the right hand side.

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Crescent205
35 minutes ago, welshpug said:

doesn't the loom have relays on it?

 

 

typically you would have one relay triggered by your switched live which will power up the injectors coils and ecu, and a second one that the ecu triggers.

 

connect a fused permanent live to both, take a switched power for the fuel pump relay from the first for the switching side, then the ECU pulls that to earth.

No relays, the ecu was harshly wired! Ok, I thought i could somehow use the tachometric relay but it seems not.

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Daniel306

I used the original fuel pump relay switched from the Emerald, Then the 12v sensors and Coil are fed from pin 5 on the pump relay

 

Pin 7 and 10 on the pump relay are fed from pin 20 on the Emerald, but mine is a Ph 1.5 so i dont have a  tachometric relay

Edited by Daniel306

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Crescent205

Oh, I thought all gti's had a tachometric relay?

 

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Daniel306

Im not sure, i though it was only the late cars but it could be the other way round? My original engine loom is completely gone and replaced with a home made Emerald 

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Andy

I did the following with an Emerald K6 and bodies. The feed to the pump exits  the fuse box via a white wire. I unplugged this from the fuse box and extended it into the engine bay, where it met up with an aftermarket relay . The relay got its 12v from a bespoke fuse box on the bulkhead, but you could take a supply from, say , the main power feed box on the slam panel if you still have that, then use a fused relay for safety. You can also use the same 12v feed to go to the live side of the trigger on the relay, and then use the switch to earth trigger from the Emerald to fire up the fuel pump. 

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Crescent205

ok.... Thanks for your replies with this but I managed to utilise the original tachomteric relay after some head scratching and multimeter work! Basically the racho relay need 2 lives to fire it (one for cranking and one ignition switched).  I didn't need the crank wire so i jumped that over to the ign switched live, then took the earth over to the emaerald for that to fire it. I don't know how it took me so long to work it out but that relay fried my head because of it needing 2 lives to fire it.

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Rossco

Hi I was wondering if anyone had the wiring diagram for a mi16 loom as I can not get mine to run. Fuel pump does not run no spark either 

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Crescent205

that sounds like the infamous brown plugs!!!

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