Club G40 Forum

Technical => Engine and Transmission => Topic started by: dub-disaster on May 21, 2011, 10:25:16 AM

Title: uprated Fuel pump wiring ?
Post by: dub-disaster on May 21, 2011, 10:25:16 AM
Got a new 135 lph inline pump, there's no rating on it power or current wise just wondered if that standard cables would need uping in size and if so do they run the length of the car? Also the rubber hoses at the back of the car have all perished so shall be replaced, shall I replace the nylon ones aswell not sure if it degrades the same over time only the nylon lines from Vw are £20 a piece minimum and ther is 4 of them.Thanks  
Title: Re: Fuel pump uprated wiring ?
Post by: Fred on May 21, 2011, 11:00:13 AM
I`ll guess it has 2 wire connections.

Make up to short Leads with proper spade connectors if thats what it has.

Get either someone who knows how to use a multimeter or your self.

Connect the Negative - of the fuel pump straight to to your Car battery Negative Terminal.

Set the multimeter to the 10 Amp max setting or whatever it has.

Do not use a low setting or you may damage the meter.

Usually the multimeter will have a dedicated Amp testing socket seperate
to the Volts Ohms socket.

Plug the red probe lead of the meter to this socket.

Now the bit to get right.

Turn on the Multimeter.

Connect the Multimeter red positive + Lead to the car battery Positive + Terminal.

Connect the Black Multimeter Probe to the Red + connection of the fuel pump.

The Fuel pump will spin straight away unless you put a spare switch inline somewhere on
the positive wire.

The Multimeter will now display the Current draw.

I would suggest using wire of the same size and spec as under the car
and if too thin will heat up with higher current draw and will be a good indication
That it`ll cope.

Don`t make Shite sloppy connections while testing by holding bare wires to the meter
test leads as they will also heat up and burn your fingers, use electrical connector block.

Though i suspect you`ll be ok as it`ll probably be a few amp maximum anyway.

Hope this helps and if your still unsure i will connect something to my multimeter
in that manner and take pics to make it obvious for you.

Regards, Fred.
Title: Re: uprated Fuel pump wiring ?
Post by: dub-disaster on May 21, 2011, 12:30:21 PM
Thanks for the in depth info there fred, although I thought running a fuel pump dry even for a quick flick can damage them. Also you wouldn't be able to get a true reading as the pump wouldn't be under load.
    I know how to terminate it just wondered if anyone knew the current draw or power rating of their uprated pump and I could make a geusstimation from that.think I may just phone the manufacturer and ask them
 
Title: Re: uprated Fuel pump wiring ?
Post by: grantvw on May 21, 2011, 10:46:43 PM
hello i fitted a bosch 044 pump and upgraded the wiring to some heavy wire forgot what guage it was, i basicly ran a wire from the pump to the chassis (ground), the main power cable the full length of the car to a relay next to where the original pump relay is that runs the injectors idle valve and lambda probe, i then took a power feed direct from the battery to the relay and an ignition feed from the original relay to put it onto its own circuit and don't for get to put an inline fuse too hope this helps 
Title: Re: uprated Fuel pump wiring ?
Post by: Fred on May 22, 2011, 12:00:12 AM
lol! Yeah i forgot the don`t run the pump dry bit.
Glad you knew and didn`t try.

Fred.