fuel pump wiring
Turbo Mini Forums

right guys and girls, have just spent half an hour or so looking through old posts, but i cant find an exact answer so.....

how do you wire up the fuel pump? i am using mjlj so i aslo need a igntion live to this. i have an inertia switch which will obviously be the first in line after the ignition, then power to relay, then from relay off to fuel pump and mjlj?

anybody confirm/correct this for me?

cheers all.
Pete

And on the 7th day........... God created turbochargers!

It is up to you how you want to do it to be honest.

I have wired mine up in the original metro method, so that in the event of a oil pressure loss the fuel pump is switched off.

An inertia switch is then in the live line to the fuel pump itself.

There is no right or wrong way of doing it really, it is up to you!

Like so-

Or like this
http://www.eraturbo.com/technical/technical.htm

1293 Turbo mini

All sounds very thought out, however it is not best practise to rely on the relay to break the circuit to the fuel pump, the inertia switch should be placed directly in the feed to the pump so that this ensures a physical break in the supply in the event of an off.

Maybe a bit OTT but this is how stuff is done on industrial machinery where there is very real potential to kill people.........

err mine just comes off the brake light switch live...............

one cable front to back.....

i know that cant be strictly true nic, there must be a switch in there somewhere because iirc you once manganged to forget to turn it on didnt you?!?! :)

so then, going on what tom said, the inertia switch needs to go inline with the fuel pump... ok, no biggie, i can easily get another so ive got one to each, but my main concern is will the inertia switch take the current without burning out? i havent got it handy, but iirc the wires on the back ave very thin...... ie, signal current only (bad term i know, but it makes the point....)

mine is a ford item courtosy of someone on here..... (wolfie poss?) maybe others will safely carry more current.....

And on the 7th day........... God created turbochargers!

oh yeah, theres an inline switch in there for security

i did get an inertia swtich for it, but typically that was damaged in the accident in the car it came from!!haha

might see about wiring it in in a better way one day

Dragging up and old post here but I can't get my head around how Tom's 5-pin changeover diagram would work given that the oil pressure switch is short on low pressure and goes open circuit at high.



This is my understanding of the state the relay would be in with the key in second position (IGN +ve) and the engine running with pressure.

Oil pressure switch is open circuit ∴ relay is in the de-energised position (bridging pins 30 and 87a) and the fuel pump is off.

Edited by andygardner on 19th Jun, 2008.

You have 87 and 87a in the wrong positions and show the relay energised (ie, bar pulled toward the coil).
Re-number it with 87a at the top and 87 below and re-draw it with the bar to the top right (now 87a) but leave the wiring drawing alone (ie, IGN +ve still links to top right) and you'll see it works.


The relay should be energised when there is NO oil pressure so the fuel pump needs the starter feed. As soon as oil pressure builds, relay drops OUT and pump gets it feed from ignition (as above, engine running with oil pressure).

Lose oil pressure (oil pressure switch contacts close) and relay energises so you lose ignition feed to the pump (unless you operate the starter at the same time...).

Schrödinger's cat - so which one am I ???

You're right! I'd read the diagram on the side of the relay wrong. Put an avo across it does indeed work as you described.

Sorry for bringing up an old topic, but at least i used the search :)

i've just got my hands on a metro turbo fuel pump and i want to clarify that i'll be wiring it in correctly.


But i have a few questions:

Where is the best place to mount the fuel pump, in the boot or underneath the car?
what type of oil pressure switch do i use, standard mini one?
Do i need to have any fuses fitted inline with the ignition and starter feed? If so what sizes?
Is my diagram correct?

I've also added an extra swicth which is inline with the ignition feed to the relay in the event of someone trying to steal it and hot wire it, the switch will need to be pressed for the relay to work and thus the fuel pump, is it fine to put it inline with the igntiion feed or would it be better anywhere else?

and lastly is there anyway of wiring a warning light to the inertia switch to show if it's been tripped?



thanks :)

^^^^^