Erratic Power To The Fuel Pump?

[scottishtaffy]

last year had a pump failure that turned out to be a dodgy earth wire. sorted by earthing to the boot floor. now seems to have a erratic live supply. as would not start the other week but as i have a constant live to the boot for the subs i wired that to the pump and it started. got hhome then when i re wired the loon live it was working again. then to day i drove up to my pals and back home fine then half anhour later when i went to start it then the pump wasnt humming again! wtf put sub live back on and pump goes.not sure if its a relay problem and if so where is the relay? or a brken wire some where. any ideas peeps?

[euan_r]

The ecu triggers pump by switching the earth to relay to 0v. The relay is under the drivers dash right up nearly at screen on early classics iirc, its cylindrical with green connector. Cant recall if output side of relay is switched earth or positive.

[DR Motosport]

Also check the white multi plug connection under the rear seat before it drops through the floor to the tank. Seen a few of these now starting to break down on the early classics.

[scottishtaffy]

thanks will try the plug

[specdogger]

Do you have to charge it before going out like a mobile

[scottishtaffy]

funny thing is with it is that like the other day i started it no bother drove round to my pals and stopped then drove home but when i went back out there was nopower getting to the pump. when i put the cocstant live on , pump was buzzing and car started. then after a wee while power was back into the loom live. but now there is no power again so have to run with the live on then once stopped unplug it. think i will put a rally style pump switch on the dash i think now.

[scoobywho]

Thats a good idea, would look quite good on the dash as well

[scottishtaffy]

jobs a good un and one rally style switch fitted to the dash, complete with light to remind me its left on and also wired to go dead once turbo timer has counted out. tho would like a relay like a heated rear window demister that once ignition is off then when you turn it back on the switch is still dead untill you switch it on again.