13 replies to this topic

[RsSpyder]

Hi all,

I have an electric external fuel pump fitted to my car. Its not currently wired in, there are 2 terminals on it, presumably live and earth. Can anyone advise me as to where to take the feeds from? The live in particular as i guess i can earth it where the pumps mounted in the boot.

Many thanks.

[blue min 1]

use a switched live ie when you turn the key then put a seperate fuse and switch in so you can turn the pump off when you leve the car if the pump is not working then the car wont go






mike

[Cooperman]

As above, but a really good security idea is to run the power feed from the fuse to a 'hidden' switch, then to the pump. That way, if someone tries to steal it, it will start, then stop a short way down the road. It's unlikely a thief will want to be on a public road trying to identify why the car has just stopped.

[blue min 1]

lol forgot to say hide the switch , and rember to turn the switch on when you get in not what i still keep doing




mike

[RsSpyder]

Cool, will look into that. Live feed should just come from ignition right?

[stevede]

For additional safety, wire it through one of these as well


http://cgi.ebay.co.u...=item27bb3da428


Regards

Steve

[woodsy483]

I found these useful

http://www.turbospor...p...&viewfull=1

http://www.theminifo...x...61191&st=15

[RsSpyder]

Hmm i'm a bit confused now. My pump isnt a facet pump, it looks like this:



So do i need to fart about with a relay and such? Im sure ive seen these before and i thought the wiring was quite simple?

[SolarB]

So do i need to fart about with a relay and such? Im sure ive seen these before and i thought the wiring was quite simple?

It can be simple, but it can be as complicated as you like.

As a minimum the pump needs to be fed from a switched 12V supply initiated by the ignition key and the circuit needs to be protected by a fuse.

The pump may need to be switched by a relay. You'll have to do the sums for this by working out how much power the switched circuit is already supplying and how much additional power the circuit can safely supply.

Some people install a second hidden switch on the power line as a security measure but it's only for security and not essential.

If fitted the impact switch is installed on the 12V line. This opens and cuts the 12V supply to the pump in the event of an impact. These are a good idea and it's not a lot of work to fit one.

[minifan333]

Is ok to use this scheme



and this relay

http://www.minimania...1/InvDetail.cfm

For facet solid state pump?
Thanks

[dklawson]

Minifan333, regarding the schematic and relay... "yes and no".

The schematic shows the pin out for a standard Bosch/ISO relay (based on the pin numbers). The MiniMania relay is a Bosch/ISO relay but at $40 it is extremely over priced. Check your local parts store and you will be able to buy them for 1/4 that price. Check eBay and you will be able to buy them in lots of 5 pieces (with relay bases to plug them into) for about half that price.

Regardless, while the relay is great, it does not provide any fusing or safety switches. As suggested above, those are safety features you may want to incorporate but the decision is yours. Early Minis with electric pumps had no safety features and did not even have a fuse on the pump power wire.


RsSpyder, your pump is an SU style pump. I can't tell if it is original or aftermarket. However, pumps (including SUs) work better as "pushers" than "pullers". Your mounting location is a bit "high". The original SU pump mounting location was on the rear subframe below the RH fuel tank. The pump was gravity fed so pump suction was never an issue. If you really want your pump in the boot, mount it as low as possible. Keep in mind that the SU pumps are noisy, the Facet pumps (solid state bricks) are noisier. The seat back may prove to be a great "sounding board".

[1964Woody]

I hope it is OK to revive this thread rather than starting a new one. I am just about to install a Facet fuel pump once it arrives from the supplier (thanks to Cooperman for the kick in the pants to go that way rather than a new mechanical one). I was planning to use the above wiring diagram with the addition of an inertia switch for additional safety. A couple of questions:

1. There is a fuse in the diagram from main power to Relay terminal 30. Should there also be another fuse on the switched power to Relay terminal 86? And what should be the amp rating of the fuse(s) and the wire?
2. Where in the circuit should the inertia/safety switch be? I think it should be between the fuse and terminal 30 but am just looking for confirmation or a better opinion.
3. In terms of the inertia/safety switch, is there one specifically rated for Mini (mine is a '91 Mainstream) or will one rated for other small vehicles (ie Ford) provide the same performance? I ask because those parts are far more accessible to me in western Canada.

Thanks.

[dklawson]

1) A fuse on terminal 86 would be optional, not necessary. If it will make you more comfortable then by all means add it. The relay will not draw much power so only a small amp fuse is required. Most normal automotive hook up wire can handle over 10 amps so a 3 Amp fuse for the relay would protect your wiring and allow normal relay operation.
2) I am not sure about the inertia switch. I would base your decision on the current rating of the inertia switch and the current draw of the pump. Without having either set of data in front of me I would suggest... if the inertia switch is rated for 5 Amps or less place the switch inline with the 86 terminal like the fuse you asked about above. If the inertia switch is rated for more than 5 amps then you can certainly consider putting it inline with terminal 30. Compare the current rating of the switch and pump to guide you in the decision. The inertia switch must be rated for more current than the pump draws if you choose to put the switch inline with terminal 30.
3) The inertia switches are typically designed with a G-force rating and operate with some form of mass inside going "off center" to trip the switch. Therefore, the switch should not be at all dependent on the car. Any switch you find should be OK as long as you have a good place to mount it. Orientation will be important. So, if you get a Ford inertia switch, mount it in the same orientation as Ford would have installed it in the original vehicle.

[1964Woody]

Thanks Doug.