Fuel Pump Wiring

[hcmini1989 16]

right i need to do the wiring for my fuel pump and my megasquirt. problem is im being a lazy sod and want to use the wiring thats already going to the pump so ive pulled my back seat up and there are 5 wires going through the floor and i just need to know wich ones are live and wich is earth.theres 2 thick ones a white one and a green one so are theses the pump ones .and the other 3 small ones for the sender in the tank thanks for any help

[pug_ham 244 3 Cars]

Wouldn't it be easier to find the fuel pump wiring by the tachymetric relay?

 

It should be the thick white wire iirc, green is the earth but these two ought to be in a two pin plug that only fits into the fuel pump.

 

Graham.

[pugpete1108 62 1 Cars]

aren't these oposite using megasuirt?

 

pug use a switched earth iirc and megasquirt using a new pump relay switches the live instead

 

on mine i have given it a direct earth (thick yellow green wire) and run the live to the relay (blue wire)

 

check them using a direct live and earth to the battery or other 12v source you will hear it whine when it works

 

megasquirt only switches to earth not live, unless you plan on using the relay to switch the earth and running a permanent live to the pump which is not advisable unless fused obviously.

 

or are you using the original relay and using the ms to operate it?

Edited October 11, 2009 by pugpete1108

[hcmini1989 16]

Wouldn't it be easier to find the fuel pump wiring by the tachymetric relay?

 

It should be the thick white wire iirc, green is the earth but these two ought to be in a two pin plug that only fits into the fuel pump.

 

Graham.

ive tried finding the relay for the pump but it has a mi engine in and the wiring loom is a complete mess there`s relays all over the shop .so just easier to take the wires going from the pump then ill cut all the old loom out when im finished thanks for the help

[hcmini1989 16]

aren't these oposite using megasuirt?

 

pug use a switched earth iirc and megasquirt using a new pump relay switches the live instead

 

on mine i have given it a direct earth (thick yellow green wire) and run the live to the relay (blue wire)

 

check them using a direct live and earth to the battery or other 12v source you will hear it whine when it works

 

 

its ok just needed to know wich wire does what

[welshpug 1,662]

the wire for the fuel pump will still be in one of the 2 brown plugs under the dash next to the steering column even if its an Mi16 loom with the two relays or the gti loom with its tachymetric relay.

Edited October 11, 2009 by welshpug

[kyepan 291]

the wire for the fuel pump will still be in one of the 2 brown plugs under the dash next to the steering column even if its an Mi16 loom with the two relays or the gti loom with its tachymetric relay.

what he said.

 

Wire 76(possibly 76a) goes from one of the relays probably found in the engine bay(mine are in a box together by the drivers headlight, you should have two together) to the fuel pump (via the fuse board).

[paulsupervts84 0]

would it not be easyer to get a conversion loom what just plugs straight in

[hcmini1989 16]

would it not be easyer to get a conversion loom what just plugs straight in

iye probably would .but nobody seems to make one for megasquirt and it is cheaper to do it this way on a bit of a budget

Edited November 19, 2009 by hcmini1989

[Richie-Van-GTi 73 2 Cars]

If all else fails and the wiring is totally bodged pick it up at the fuseboard and run an inline fuse and a new relay wired for the MS setup. Thats how I done mine to eliminate any future faults. If your making a new wiring loom with MS then simplify everything else first. makes future jobs 10 times easier.

I originally made a small fuseboard for all the engine and fueling under the steering wheel so it was completley seperate from the chassis wiring other than the ignition switch. All fault finding after that was a piece of P.