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how much to install a kill switch?

[Deleted User]

they work by controlling the fuel supply?

wouldn't mind putting one somewhere in the car.. someone goes to steal it without hitting the switch and the car doesn't go very far. i know my uncle had it on his 6 series.

thoughts? it's a 1990 bmw e30.

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JHMEG

Maybe €1 for a switch and about 20 mins to do a good installation.

[Deleted User]

is it an electronic switch then or a valve sort of thing?

JHMEG

Electrical. Quickest way is to lift up your back seat and install it inline with the power to the fuel pump.

Wibbs

Make sure it's an 18 amp switch so it doesn't have a chance to burn out. If you're going to run the wire to the switch any distance you may need a relay(cheap too) but I may be wrong there. Better counsel will be along I suspect.

JHMEG

18 amp fuel pump... jeez it's not pumping fuel to the moon! Fuel pump fuse is a piddly 7.5 amp. Relays are not necessary.

[Deleted User]

JHMEG wrote: »

Electrical. Quickest way is to lift up your back seat and install it inline with the power to the fuel pump.

Wibbs wrote: »

Make sure it's an 18 amp switch so it doesn't have a chance to burn out. If you're going to run the wire to the switch any distance you may need a relay(cheap too) but I may be wrong there. Better counsel will be along I suspect.

thanks lads.. food for thought while i've a bit of time of work.

Wibbs

JHMEG wrote: »

18 amp fuel pump... jeez it's not pumping fuel to the moon! Fuel pump fuse is a piddly 7.5 amp. Relays are not necessary.

Resistance increases with the length of the wire. You run a wire from your pump to your switch with a round trip of 6 feet you'll draw a fair whack of current. A relay cuts that as an issue. That's one of the reasons they're in car alarm brains. I've heard of problems with fuel cutoffs for that reason, blowing fuses, burning out crappy switches etc(and crappy connections in the first place. Twisted wires and gaffa tape.)

JHMEG

Wibbs wrote: »

Resistance increases with the length of the wire

No to any consequential amount over such a short run.

Relays are used when the load is too much for delicate electronics to switch.

Anan1

Deleted User wrote: »

they work by controlling the fuel supply?

wouldn't mind putting one somewhere in the car.. someone goes to steal it without hitting the switch and the car doesn't go very far. i know my uncle had it on his 6 series.

thoughts? it's a 1990 bmw e30.

If you want, i'll move this over to classics?

Wibbs

I'm just a better safe than sorry merchant I suppose. If it was 3 feet of a curcuit I wouldn't bother either. If I was running a wire from the pump all the way to the dashboard I would. The fuel pump draws enough of a current and on top of that the resistance may even reduce your fuel pressure. As I say I'm a better safe than sorry type and I have seen fuel cutoff switches give trouble with long wiring involved. It happened to me(switch burnt out over a few months) and it was an auto electrician that put me onto the relay notion.

JHMEG

When I owned older Jap cars I had the simple type I described. Had them on a few cars and never had any problems.

Matt Simis

Deleted User wrote: »

wouldn't mind putting one somewhere in the car.. someone goes to steal it without hitting the switch and the car doesn't go very far. i know my uncle had it on his 6 series.
thoughts? it's a 1990 bmw e30.

So after they get down the road and it cuts out.. then what exactly do you think they will do? Ive read of people in the UK that descibed how a "my car was robbed during the night" situation escalated into "I was dragged out of bed to show them how to start the car.. and it was robbed during the night" scenario.

JHMEG wrote: »

18 amp fuel pump... jeez it's not pumping fuel to the moon! Fuel pump fuse is a piddly 7.5 amp. Relays are not necessary.

Depends on the power of the car/pump really. The bigger Audis (twin turbo or big turbo) have 20amp Fuel Pump relays as standard. I had to install a 30amp relay when wiring up the mega Denso pump as it draws a whopping 21.5amp current at full whack (which admitedly Im not going to get to without bigger turbos, but safe than sorry and all that).

JHMEG

Matt Simis wrote: »

Depends on the power of the car/pump really. The bigger Audis (twin turbo or big turbo) have 20amp Fuel Pump relays as standard. I had to install a 30amp relay when wiring up the mega Denso pump as it draws a whopping 21.5amp current at full whack (which admitedly Im not going to get to without bigger turbos, but safe than sorry and all that).

Fair enough, but in this case I did a quick google and the E30 seems to have a 7.5 amp fuse.

Is that Denso a dual speed pump?

Matt Simis

JHMEG wrote: »

Is that Denso a dual speed pump?

It's the Denso 195130-1020, from a Supra Twin Turbo!

290lph at 14v and scales with higher voltage. To lower output the car sends 50% voltage to it, so I dunno if that really counts as dual speed.

darragh o meara

I have put a good few of these switches in cars over the years and I find the best place is on the return wire from the inertia switch, usually located in the drivers or passengers footwell. Only tip ill give is to ake sure you connect it right and crimp and solder any connections you use as if its any bit loose it could leave you scratching your head wondering why the car wont start

Farls

They are a good and cheap idea but if the robber gets so far down the road and the car stops I think their next course of action might be to burn it out. Which kind of defeats the purpose then.

[Deleted User]

Anan1 wrote: »

If you want, i'll move this over to classics?

i'm sorry but i don't see how this thread has anything to do with classic cars just because my car is 19 years old. thanks though..

Matt Simis wrote: »

So after they get down the road and it cuts out.. then what exactly do you think they will do? Ive read of people in the UK that descibed how a "my car was robbed during the night" situation escalated into "I was dragged out of bed to show them how to start the car.. and it was robbed during the night" scenario.

my car wouldn't be the kind to be stolen by professional car thieves and i can't imagine a joyrider breaking into my house.. i'd imagine he'd run away. scary thought tho..!

Farls wrote: »

They are a good and cheap idea but if the robber gets so far down the road and the car stops I think their next course of action might be to burn it out. Which kind of defeats the purpose then.

i live in an estate near galway city centre.. unlikely in my case but i see your point.!

Anan1

Deleted User wrote: »

i'm sorry but i don't see how this thread has anything to do with classic cars just because my car is 19 years old. thanks though..

Two reasons:
Classic owners often fit kill switches to their cars, owners of modern cars do it far more rarely. Also, most people would consider an E30 to be a classic. Anyway, it's up to you.

Wibbs

Matt Simis wrote: »

So after they get down the road and it cuts out.. then what exactly do you think they will do? Ive read of people in the UK that descibed how a "my car was robbed during the night" situation escalated into "I was dragged out of bed to show them how to start the car.. and it was robbed during the night" scenario.

Well at that point show them. Its rare enough though and hopefully you will have rung teh local Garda station as they drive off. That said, this is where it tends to fall down. I and friends have had personal experience of their woefully slow response times. The last time a car of mine was pinched(and what led me into looking at the whole car security thing. They had bypassed a standard expensive alarm install in seconds. After I got it back I could see why. I could have done the same and I'm no electrician), I heard them start the car and saw them drive off. As they drove off I was on to the local cop shop which is literally less than a 5 minute walk away telling them what had happened. They didn't do anything on the night and finally showed up two days later(and then started the 20 questions routine on me), by which time I had gotten the car back(luckily I knew another Guard who showed me where they usually take the cars if they're not burning them out right away. Common knowledge apparently).

On another occasion a mate of mine's wife who was on her own in the house heard noise outside. Looked out the window and saw scum trying to take her neighbours car. they couldn;t get it started, so moved on to another one. They went through and caused door damage to three cars on their road. She rang the Guards within minutes of seeing them at the first car. She found out that two others had rung them too. The scum were in plain sight for well over half an hour. the local station is a ten minute drive away. they didn't show up until the next morning. I could give example after example of this kinda thing. So yea if scum threaten you or your family give them the car. Don't overly rely on the cops showing up in my experience at least. Property crime, in particular car crime is not really given much precedence IMHO.

Depends on the power of the car/pump really. The bigger Audis (twin turbo or big turbo) have 20amp Fuel Pump relays as standard. I had to install a 30amp relay when wiring up the mega Denso pump as it draws a whopping 21.5amp current at full whack (which admitedly Im not going to get to without bigger turbos, but safe than sorry and all that).

Plus the main reason I would rig a relay is not just the amperage of the pump itself but the length of wire you're intending to use as the extra kill circuit. Go over a few feet and you're increasing resistance, which if nothing else will lower the fuel pump power. As I said I had a switch burn out before(5 foot circuit) and a car sparks told me that was the main reason. So I figured better safe than sorry.

Omeara_darragh wrote:

I have put a good few of these switches in cars over the years and I find the best place is on the return wire from the inertia switch, usually located in the drivers or passengers footwell. Only tip ill give is to ake sure you connect it right and crimp and solder any connections you use as if its any bit loose it could leave you scratching your head wondering why the car wont start

Inertia switch? Pardon my ignorance.:o

Farls wrote:

They are a good and cheap idea but if the robber gets so far down the road and the car stops I think their next course of action might be to burn it out. Which kind of defeats the purpose then.

This gets said a lot and I can't see the logic. The chances are very high they're gonna burn it out anyway, or break it up for parts and then burn out whats left. At least this way you don't give the scum the satisfaction of "joyriding" or making money from spares. the latter really písses me off too. If there was no one buying cheap dodgy parts they wouldnt be stripping them for same.

Maybe cars differ, but any I've done a fuel pump kill on, they only run for seconds or not at all.

JHMEG

Matt Simis wrote: »

It's the Denso 195130-1020, from a Supra Twin Turbo!

290lph at 14v and scales with higher voltage. To lower output the car sends 50% voltage to it, so I dunno if that really counts as dual speed.

Hard to know.

How's the E85 going? I've been running a 2/3 petrol 1/3 E85 mix in everything lately, currently a 1.2 Jazz I've inherited. No problems whatsoever, and at a 1/3 mix brings down the cost of a litre by about 5c.