Have you Rewired your Fuel Pump ?

[Spartacus]

The way I will be wiring my fuel pump is to use a new relay (not 13 yr old), energise its coil from the ignition switch (ign on). Then use a nice thick cable direct from the battery (inline fuse) via the relay contacts straight to the pump. Doing it this way will eliminate all the old loom connections, resistor, extra relay contacts etc.

[antnicuk]

i did it that way on my fc, only prob is that he fuel pump is pumping when the ignition is on, so if you stall or have a problem, the pump still pumps, ie in an accident where the car would stall the pump would normally stop but wiring like you say it wont.

Only a slim chance of being a problem but that maybe what caused blitzboys car to go up.

[chris]

i did it that way on my fc, only prob is that he fuel pump is pumping when the ignition is on, so if you stall or have a problem, the pump still pumps, ie in an accident where the car would stall the pump would normally stop but wiring like you say it wont.

Only a slim chance of being a problem but that maybe what caused blitzboys car to go up.

Absolutely right, it is very advisable to keep the original relay switching circuit, as you say this gives you the safety cut features if the worst were to happen.

If you do choose to replace the relay I would advise using something fairly hefty with 9mm contacts rather than the standard 6.3mm then retain the Black and light green (B/LG) relay coil supply and Blue and Red (L/R) relay coil switch wire (controlled by the ecu)

[Spartacus]

Is the safety cut a feature of the ecu and do you know when it activates?
If it is ecu controlled you could use the method above but use the ecu feed to energise the relay coil and keep everything else the same.

[chris]

Is the safety cut a feature of the ecu and do you know when it activates?
If it is ecu controlled you could use the method above but use the ecu feed to energise the relay coil and keep everything else the same.

The ecu will initially switch this relay on for a couple of seconds to \'charge\' the fuel rail, when the ignition is switched on, it then switches again (from memory) when it recieves a cranking signal from the crank angle sensors, if you plough into a wall, there is a good chance the engine will stop, hence the fuel supply stopping (on some cars there is an impact switch which pops up in the case of impact to stop the fuel pump (mazda do not have this function)
If you are looking to replace the relay I would recommend something like this
http://www.vehicle-wiring-products.eu/VWP-onlinestore/relays/relays.php#high


(R70 and R70N are more than capable) They also sell maxi fuses, wire, crimps etc etc

[Spartacus]

Thanks for that, following a bit of a search I’ve found out that the LS1 ecu has the same function in that it supplies a signal for a couple of seconds but if it doesn’t see the engine start during that time the signal is cut.
So rather than using the Ign on I\'ll use the feed from the ecu to energise the relay coil and use a fused  supply direct from the battery to power the fuel pump.

[antnicuk]

i think the other reason you cant just use the existing power wires to switch a new relay with new power wires is because they only see 6 volts at times and its not enough to open the new relay

[Spartacus]

From the look of the circuit diagram you could either jumper the existing relay at the front, or jumper the resister (with a suitable cable) and have a constant battery voltage rather than the lower voltage. Obviously doing this alone would still leave you with the problem of the potential loss through the existing cables and connectors, but you could do it just to supply the trigger for a new relay. Personally I\'d go straight to the ecu  trigger to energise a new relay and run a new cable to the pump so you loose all the old relay contacts, joints and cable.

[chris]

The down side of jumping the relay is that you still retain any additional alarm cuts that may be further down the line from the ignition switch.