owenglen

can i bypass fuel pump relay and just put an on off swith on it
that is the q

stickertone

you can... but why would you want to.. its there for a reason... why noy just put a switch in the wire which leads to the pump after the relay ....

koo

yes you can,
but why do you want to do that?

martysmartie

iTrader: (1)

I would say no and IMO thats a terrible idea hence why Ford didn't do so, the pump draws quite a bit of power and so the reason for the relay, it will also run permanently with a switch, it doesn't with the relay.

The switch will need to be a up to the job as your average switch will break down which could have disastrous consequences not just electrically but to the engine as well! It's not good practice to fiddle with anything fueling wise, I guess you want it for security purposes? If so there are far better ways of immobilizing the car.

Martin

owenglen

having problems with relays been though 2 in 2 weeks so switch it is

martysmartie

iTrader: (1)

Then you need to find why the relays are going faulty, have you tried to earth the relay to see if it's runs, may be the trigger side of things which is the problem?

Martin

stickertone

it could even be a faulty pump..... drawing too much current. i'd get it checked out properly by an auto electrician..... if you bypass the relay it will damage the next weakest link like melt the fusebox. Get it done properly mate..

martysmartie

iTrader: (1)

Depends on how competent you are with electrics but it's very basic stuff anyway, it may even be worth rewiring the fuel pump, the demand on this circuit coupled to 20 odd year old wiring is not the best, especially if it suffers problems in this area like the Cosworth does. There may be looms you can buy for this (Like you can for Cosworth's), or very easy DIY!

Martin

tabetha

VERY dangerous imo to put through a switch, imagine the worst you are involved in a crash, the fuel rail or pipe splits/gets broken and you are unconcious you'll have fuel pumping out helping a fire along nicely, at least you'd be nice and warm!
What sort/make of relays have you been using, if the cheapo ones out of car shops some of these are very sun standard, what exactly is going faulty with the relays.
It sounds more like a connection problem than relays going duff, the 044 group a pump can only draw 18 amps at lockout, but as said add this to original wiring and you will have trouble, defo needs a rewire here and the fan.
If wanting security just cut into the wire and put a switch on number 85(earth/ecu) or 86 live(from ignition), 30 is input from battery, 87 is the output to the pump.
When I rewired my one I put the new relay up behind the rear seat, in the metal work around the "shelf" and seat back there is a nice 8mm hole each side just right to hold a relay holder, wire to this pop a relay in, so when at shows etc simply unplug the relay to stop pump.
It's essential for safety to keep some kind of auto cut out on it, like the ecu feed cutting it out when engine stops(as in accident) or via a impact cut off switch fitted to all later cars.
tabetha