Kill Switch. S3 fuel pump.

Technical advice Q&A

Topic author
JoeLondon
Posts: 67
Joined: Sun Mar 08, 2020 6:25 pm
Great Britain

#1 Kill Switch. S3 fuel pump.

Post by JoeLondon » Sat Sep 12, 2020 2:54 pm

Good day folks.

I would like to fit a kill switch for anti theft to my S3.
I was originally thinking of the coil, as my current mission is unplugging it every time I park. however, now considering the fuel pump as an easier target for my skill set (lack thereof), as it's already inside the car and I won't need to faff around under the dash.

Sparks are not really my thing, I'm fine doing it, just not so fine knowing what I'm doing, I'd like to check.

I would cut one of the wires going to the pump, run to a small toggle switch. But which wire and what guage of wire should I use, does it need a fuse or relay.

Of the 2 wires I see to the fuel pump, there's the Darker grey(black?) Single line, or the crusty yellow (white?) Line that I think splits to 2 wires toward the pump. My instinct would be the single black line, hook the toggle switch without any fuses etc.
Joe
1972 S3 2+2 V12 Manual, FHC, Racing Green

Link:
BBcode:
HTML:
Hide post links
Show post links

User avatar

Heuer
Administrator
Posts: 13526
Joined: Sat Mar 01, 2008 5:29 pm
Location: Nottinghamshire
Great Britain

#2 Re: Kill Switch. S3 fuel pump.

Post by Heuer » Sat Sep 12, 2020 3:30 pm

A key switch would be more secure:


The black is earth and the two white wires each go to one of the pumps (there are two). I suggest you unplug the two whites from the connector and put the switch between the two. You can mount the key switch in the boot area adjacent to the pump. You will almost certainly forget to switch it back on and come to a spluttering halt in the middle of traffic - happened so many times to me!
David Jones
S1 OTS OSB; S1 FHC ODB

Add your E-Type to our World Map: viewtopic.php?f=1&t=1810

Link:
BBcode:
HTML:
Hide post links
Show post links


Topic author
JoeLondon
Posts: 67
Joined: Sun Mar 08, 2020 6:25 pm
Great Britain

#3 Re: Kill Switch. S3 fuel pump.

Post by JoeLondon » Sat Sep 12, 2020 5:47 pm

Thank you David,

2 pumps makes sense, one for each bank I suppose.

So, solder 2 spade terminals on tails to each terminal of the switch?

Key switch also makes sense. Although I was contemplating somewhere in easier reach of the pilots seat for discretion when leaving the car, and suspect that as small as it is, the key switch might be a tricky one to hide. However I'll have another look now.

Thanks again
Joe
1972 S3 2+2 V12 Manual, FHC, Racing Green

Link:
BBcode:
HTML:
Hide post links
Show post links

User avatar

mgcjag
Moderator
Posts: 5933
Joined: Fri Jul 09, 2010 6:15 pm
Location: Ludlow Shropshire
Great Britain

#4 Re: Kill Switch. S3 fuel pump.

Post by mgcjag » Sat Sep 12, 2020 5:58 pm

Hi Joe.....do you use your steering lock.....Steve
Steve
1969 S2 2+2 & Building a C type replica

Link:
BBcode:
HTML:
Hide post links
Show post links


Topic author
JoeLondon
Posts: 67
Joined: Sun Mar 08, 2020 6:25 pm
Great Britain

#5 Re: Kill Switch. S3 fuel pump.

Post by JoeLondon » Sun Sep 13, 2020 7:30 am

Hi Steve,

As in the integral one? I do, I turn the wheels full lock toward the kerb. End of the day if someone wants it enough they'll take it, I get that, but I'd just rather try limit that opportunity. I think a truck with hoist is the only way it should be able to be pinched. Can't stop that. Although, I was thinking about a chain through the storm drain.. which I may actually do over the less driveable months when it's under cover and hibernating.
Ceazy..
Joe
1972 S3 2+2 V12 Manual, FHC, Racing Green

Link:
BBcode:
HTML:
Hide post links
Show post links

User avatar

mgcjag
Moderator
Posts: 5933
Joined: Fri Jul 09, 2010 6:15 pm
Location: Ludlow Shropshire
Great Britain

#6 Re: Kill Switch. S3 fuel pump.

Post by mgcjag » Sun Sep 13, 2020 7:41 am

Hi joe...i would just reinforce what David said about forgetting to switch on the pump.....it will happen and could cause problems....Steve
Steve
1969 S2 2+2 & Building a C type replica

Link:
BBcode:
HTML:
Hide post links
Show post links


Topic author
JoeLondon
Posts: 67
Joined: Sun Mar 08, 2020 6:25 pm
Great Britain

#7 Re: Kill Switch. S3 fuel pump.

Post by JoeLondon » Sun Sep 13, 2020 7:44 am

Is it likely to cause problems other than jolly red face?
Joe
1972 S3 2+2 V12 Manual, FHC, Racing Green

Link:
BBcode:
HTML:
Hide post links
Show post links


MarekH
Posts: 1066
Joined: Wed Jul 21, 2010 8:30 pm
Location: Surrey
Great Britain

#8 Re: Kill Switch. S3 fuel pump.

Post by MarekH » Sun Sep 13, 2020 7:58 am

There is no need to hack the loom.

The ignition switch fed thick white wire which goes along the right hand side of the car has a bullet connector in to the dash harness tucked into the very right hand corner under the dash. You can intercept it there to fit your toggle switch or to fit an ignition switch bypass relay. If doing the latter, then put your toggle switch into the relay winding circuit so the white wire is cut that way.

Another popular option is to simply fit an ordinary battery isolator switch somewhere.

You can fit a genuine kill switch from a scrapped xjs along this path also if you want to, to cut power in the event of an accident.

Another thing to also do is to fit a fuse for the fuel pump whilst you are there.

kind regards
Marek

Link:
BBcode:
HTML:
Hide post links
Show post links

Post Reply Previous topicNext topic