7 replies to this topic

[Ades Mini]

Hi guys I am currently fitting a facet fuel pump to my Mini and have most of it sorted as far as using a relay, inertia switch, feed from ignition live only etc but the only thing I’m not 100% on is taking the feed from the battery positive. I understand I need to take a feed and run through a 3amp inline fuse before wiring to the relay but the inline fuses I have seen for sale come with 2 short bits of wiring attached and I’m not sure if it’s ok to attach one side direct to the battery terminal? I’m concerned the cable is too small and might cause an issue between the terminal and fuse. How have you guys run a feed from the battery and if you have any pictures then great.
Cheers guys
Adrian

[Ethel]

Do that & the pump would run all the time, even when it's parked.

 

It will want a feed from ignition live, white wire. There are various way of adding extra safety with an inertia switch or using the oil pressure switch to tell if the engine has stopped.

[Ades Mini]

I am taking a feed from the ignition live and will also be adding an inertia switch but from what I have seen I also need to bring a 12v feed direct from the battery to wire into the relay via a fuse.
So on the 4 pin relay it would be,
Pin 30 positive feed from battery via inline fuse
Pin 87 to fuel pump
Pin 84 earth
Pin 85 ignition live feed
Is this not correct then as this was the way I believed others had done it.

Edited by Ades Mini, 14 May 2022 - 01:12 PM.

[Ades Mini]

The inertia switch I was going to wire between the live feed from the relay and the pump, assume that’s correct?

[timmy850]

Inertia switches have an amp rating. If it’s rated to run the pump, you can run it between the relay and the pump. If the inertia switch isn’t rated to power your pump, then put it between the switch and relay

You also need to think about where to put the fuse. If the pump goes bad and shorts out, you need to have the fuse between the pump and relay. If you only fuse the switching side it won’t do anything

[KTS]

pin 30 is power in

pin 87 is power out

pins 85 & 86 (normally) are for the relay coil - unless it's diode protected it doesn't matter which way round you connect, but by convention 86 would be +V and 85 earth

 

inertia switch can be wired in before or after the relay; it'll perform the same function either way.  personally i've put it after the relay

 

if the leads are too short on the inline fuse, you'd need to extend them, or alternatively use a relay with a built in blade fuse

Edited by KTS, 15 May 2022 - 06:42 PM.

[Ades Mini]

That’s great thanks, I didn’t realise you could get a relay with a fuse but that might be a good option. Is there a recommended size cable I should use to be safe?

[gazza82]

pin 40 is power in

Pin 30 on all my relays ... typo?