[mr_ron]

Hey guys, So I put a 12v external fuel pump on the Sierra. Its hooked up to an accessories wire so when the car is to acc the pump starts and teh float controls the amount of fuel in the bowl. It gas been workign and running better then ever

However,
I discovered today when driving, When I have my Uhf, Lights, Wipers and radio on, I can hear the pump slow down and the fuel flow slows and when I turn items off it starts to pump faster again...

Now I've looked into the Ford Alt upgrade and its not in my budget or abilities atm .. so what I was wondering is whether or not adding a relay or something to the power wire of the Fuel pump will help store power??

I know that relay is probably the wrong thing but I'm hoping someone understands me and can help..

Thanks Ron.

[atari4x4]

wire it up via a relay so it's getting power directly from the battery. use the accessory wire to trigger it.

[mr_ron]

oh ok so:

Pin 85: ground
Pin 87: fuel pump
Pin 86: acc wire
Pin 30: positive terminal
?
*note I'm only reading up on how to use relays now :s lol..

Thanks, Ron

[mnemonix]

As above. This is how it should have been done in the first place.
Relay is triggered by ignition so the fuel pump stops when the engine stops (ie: in case of a crash, it won't continue to pump fuel).
And takes power directly from the battery for optimal amperage supply. Make sure you fuse it also.

[mr_ron]

yeh I put it in myself and wasnt sure of how best to do it and I need my zook to get me to work

So my pin outs on teh relay are correct? What size *fuse should I put in the line between the relay and the pump? 15amp? :s

Ron

[89_tintop]

pin out is correct.

you want the fuse between the battery and the relay (the closer to the battery the better)

15 amps probably to big.. should say in the fuel pump packaging what is recomendedk

[pyrohamish]

Wouldn't it be better to find a wire that is at 12v when ign is 'ON'

[Rusho]

pyrohamish wrote:

Wouldn't it be better to find a wire that is at 12v when ign is 'ON'

An accessory wire would be 12v give or take due to loses, relay off the battery would be a more reliable 13.8v and like the gents above had said, through a relay is the best way to go.

Make sure you have a good earth to Ron

[royce]

when I do em I like to use 2 relays

the first relay is wired as above (use an ignition power feed not acc so its not running if you are just listening to the radio)

the second is a normally closed relay, so when the relay is activated it cuts power

wired as follows

30 - to fuel pump
87a - from 87 on other relay
85 - from 87 on other relay
86 - to oil pressure switch

so now you need the ignition on and oil pressure for the pump to work, so if you have a prang and arent able to turn the ignition off the pump wont just keep spewing fuel into the fire

[lump_a_charcoal]

royce wrote:

when I do em I like to use 2 relays

the first relay is wired as above (use an ignition power feed not acc so its not running if you are just listening to the radio)

the second is a normally closed relay, so when the relay is activated it cuts power

wired as follows

30 - to fuel pump
87a - from 87 on other relay
85 - from 87 on other relay
86 - to oil pressure switch

so now you need the ignition on and oil pressure for the pump to work, so if you have a prang and arent able to turn the ignition off the pump wont just keep spewing fuel into the fire

This.

Listen to the pineapple - It might take a bit more work, but it is the safest way to do it.

[mr_ron]

Thanks for the help guys. I'll throw one I. This arvo to keep
Me going then do the second one on re weekend.

Also I do t have packaging with the fuel pump so what size fuse would someone recommend ?

[lump_a_charcoal]

How many amps does it draw, and what size cable have you run to it?