used to be in the technical section of how to re-wire your fuel pump on a cossie

 

Here you go m8.

https://passionford.com/forum/general-car-related-discussion/227107-fuel-pump-re-wire-question.html

 

cheers fella

 

No probs pal.

 

I wonder where you got that diagram from Kev?

 

Q What happens to the METAL of a car ?
A It RUSTS!!
So why put an EARTH where it IS going to suffer from CORROSION ?
If you want peice of mind earth straight from the battery, otherwise you introduce many more points of high resistance.
The relay in the drawing is NOT SPDT it is a SPCO.
tabetha

 

Tabs

The picture was quickly drawn up by a friend of mine in Paintshop as I'm sure you can see

As regards to the relay, I've no idea but I used the same relay as him, which is why all the pins are numbered as they were indentical (I don't know if this is generic throughout relays?)

I think it was an SPDT from memory

Where would you earth then?

 

Some not so handsome person did it i believe

I earthed mine straight from the battery.

 

I earthed mine to the chassis along with several other componants....cleaned an area of chassis that was tucked out of harms way ie behind bulk head metal trim panel, drilled a M8 sized hole and made a decent earthing point using a nut and bolt to make the poll then another nut on top of the terminals.....after which all earth points were covered in petrolium (sp?) jelly (im sure most the people who use the muppet section will know what that is )

 

Seems most every Car manufacturer in the world is going to disagree with you mate. Can you imagine how many wires would be on the battery if they did that?

 

and, why are you re wiring the pump?..

yes, the std cables have corroded, degraded, and have high resistance...

your saying it like cables dont suffer

 

Going to be doing mine soon so where do people locate the new relay.

Steve

 

i located mine next to the fuel cut of switch

 

Mine too.

 

I put ours behind the carpet/cover on the rear quarter panel

You should have earthed it on the chassis like the diagram showed Kev
Leading back to the battery will give a high resistance, you want the shortest earth wire possible.

And as for my mate Gav who made it, I wouldn't like to comment on how attractive he is, as I am not that way enclined

 

I was advised to use the battery neg james.

They say you're gay only if you take it.

 

Go change it then Kev

And I have no idea what you are talking about man

 

i earthed mine out on the rear anti roll bar mount

 

Works fine as it is thanks. Plus i get 14v at idle on the secs monitor so cant be that bad.

 

I believe the SECS monitor reading is voltage going to the ECU, not related to the fuel pump in any way

You want to be measure the voltage at the pump

 

and measure under load, not at idle..

hook up a meter to your pump and go driving

 

I get battery voltage at the pump.

 

Yeah Kev

 

TBH its not really an issue as you have a Wideband AFR meter don't you Kev?

 

I do james , never take my eyes off it when flat out though.

 

if you ever have a battery voltage issue, it will happen when the pump is under load...and the turbo is on boost....hot, and cooking the alternator....

very very common problem


at idle, means nothing tbh
think,on boost,your pump has to make twice the pressure in most cases

 

Agreed. Although if its shite at idle, it saves you testing it under load i guess.

 

there is that

 

I get 13.5v flat out.

 

happy days,

what cable u using?

 

I used 10 mm stranded wire m8.

 

cool,

im re doing mine, as im moving the pump into the boot

 

Done mine when i fitted my 044 pump,wh you putting it in the boot,wont it be noisy ?

 

like having no sound deadening, straight cut box you mean?

yes im sure it will be noisy, im past caring about that now.

having in car fuel cell made...

to go with rock solid suspension, and 500ponies

its only for fun now, so to hell with practical

 

Lol,well when you put it like that !!
Does it still look like the pic in your sig m8 ?

 

apart from 18"mos

lots of changes elsewhere on it though...
check my resto thread

 

Will do it now.

 

STU,
The POINT you seem to miss is the cossie that are being worked on are not to a BUDGET, nowhere did I say rewire the whole car back to the battery for the earth side THOUGH SOME ARE.
For the minute amount of extra cost, it eliminates LOADS of potential high resistance points, WHY RISK IT IF YOU DON'T HAVE TO ?
The SPDT relay is actually a SPCO relay.
Sorry if it sounded like a dig, it was not intended as such.
Most relays are to DIN marking, as in 30/85/86/86, + on some as this pictured one 87a.
SPCO, Single Pole Change Over, a single input that CHANGES from 87 to 87a upon switching.
It can be used with no problems, but is normally for other things, the "normal" on eis SPST, Single Pole Single Throw, single input, single output on 87 when switched on.
Just as an example 10mm2 cable carries 70 AMPS continuous, with peaks at around 200 AMPS.
As anyone doing this is laying a new wire from the battery anyway, how much longer how much more cost to lay a new earth as well, for 100% security, the REASON for doing it in the first place.
It does not matter at all what you do to the LIVE, if the earth is crap the pump still cannot work correctly, as you will STILL have high resistance opposing the flow of electrons returning to the battery.
tabetha

 

I missed nothing mate. Wiring your earth to the chassis is fine, and has been since the automotive world took up the negative wearth way of wiring a car many many years ago. The battery itself is wired to your chassis, and if that point corrodes the whole fooking car stops, never mind your fuel pump.

 

I going to rewire my fuel pump when I replace the filter etc.

Can someone please tell me what amp relay and wiring etc is recommended so I can order the stuff up.

CheeRS