I'm wondering if the length of the fuel pump cable does make any different. Cuz I wanna mod a on off switch for security purpose.

 

I dont think you want to touch your fuel lines

I think its running at what 50-60 psi ? so if there is a leak its not going to be funny.

Your car already has an immobilizer. There is a new way to crack the code, within an hour, but its pretty complicated and requires the theif sniff the singal at least 5 times(the owner have to press the remote 5 times for no reason)

So, you're still pretty safe. Dont worry too much about it.

 

It's much easier to put another electrical deterrent on the car....much neater...and less likely to have catastrophic problems if you screw up

 

What I'm trying to do is not on the fuel line. It is to put a switch on the electric suppy cable for the fuel pump.

 

It should just be a 12V connection switched on the ignition. Length of the wire should not matter as long as the line is of sufficient size to transmit the needed amerage to operate the pump.

 

I'd run a switched relay..that way you have very low current draw on the switch...and you don't have to worry about the wire sizes etc at the fuel pump

 

ALWAYS use a relay for high draw circuits. Never run high currents through a switch.

 

It might be easier to disrupt the supply/control wire to the 'Fuel Pump Relay/s'. There are 2 relays which control the fuel pump- 'Fuel Pump Relay (low pressure)' and ' Fuel Pump Speed Control Relay (high pressure)'. These relays are under the hood on the drivers side (USA etc). The control wire for the Fuel Pump Relay is a Red/White wire and it would be OK to break this wire through a secret/hidden switch. This would disable both relays from operating.
- relays, photo link- http://www.putfile.com/pic.php?img=4396047

 

As far as I know, there are 3 cables. Wondering which one to be cut.

 

The wire you need to cut is WHITE with a RED Stripe. Before you cut anything check that it is the wire connected to the Fuel Pump Relay coil.

 

thanks, will check

 

Check your car against this wiring diagram. (Courtesy of Robin Yang)
http://www.hi-impact.org/ryang/modif...Electrical.pdf
The connection #6 on page 24 is the control wire you need to cut.
Take care?