Diy Immobiliser

[Jon Green]

Hi Guy's

 

Im thinking of putting in my own little switch somewhere hidden that will stop the engine from starting.

 

How is this best done?

 

Jon

[Guest charlyfarly]

We used to have an immobiliser but took it off as too much trouble.

 

But we did have a battery cut out fitted, which is very handy as it works as an immobiliser (its one of the red key type ones) and also means there are no parastic loads on the battery.

 

If you were going to go for an easy line to interupt then I'd go for the wire to the starter solenoid or the fuel pump (if you have an electric one).

 

What might be handy would be another key switch from Maplins.

 

Remember its best to crimp the wire to terminals, if you solder it you can get work hardened at the end of the solder and fail.

[Jez Morton]

I think its normal to put the switch in to break the 12 volt feed to the coil.

 

Jez

[Big Jim]

Remember its best to crimp the wire to terminals, if you solder it you can get work hardened at the end of the solder and fail.

It takes a flipping long time before that happens! and crimp connectors don't fall off? or the wire itself gets work hardened where it's crimped?

I'd sooner have soldered connectors any day over crimped ones. Crimped connectors only came in because of cost, quicker and cheaper.

[Guest charlyfarly]

It takes a flipping long time before that happens! and crimp connectors don't fall off?   or the wire itself gets work hardened where it's crimped?  

I'd sooner have soldered connectors any day over crimped ones. Crimped connectors only came in because of cost, quicker and cheaper.

As I mentioned in another thread most of my engine messing knowledge is from the marine side - its now standard practise to use crimp connectors as soldered or screw ones fail more often. To be fair there is more damp around in boats and we also use fully tinned wire.

 

And these are not the cheap and nasty ones you get in Halfords in a pack with the pressed steel clamp, they're proper ones that need putting on with the right tool that you ratchet shut and have sealant in the back of the connector.

 

A proper crimp connector doesnt fall if if its the right size for the cable and put on with a ratchet crimp tool, not pliers or the 4 quid specials.

 

If you look at almost all modern looms they're crimped connections in the sockets.

 

The problem with soldering is that it tends to seperate the wires, so they tend to work where they meet the solder and don't support each other. In a crimp they are all together - its a bit like rope being stronger together rather than as seperate strands.

 

Its a bit more expensive but you'll never have to remake them and they'll never let you down.

[Guest salty_monk]

You can also put a switch to the +side of the coil & send it to earth I think... then the engine will just crank but never start.

If fuel pump is electric you can consider a cutout there too...

 

Dan

[Longboarder]

Hi Dan, where you been? Sleeping on the beach and smoking strange herbs? A wire leading a positive supply direct to earth is usualy called a short. It will stop the car from running, possibly for weeks as you repair the damage.

Hiding a switch to give a constant earth to the negative side of the coil is easy and more effective than breaking the positive supply.

 

Nigel

[Jon Green]

Thanks guys,

 

I think i'll go for a switch on the negative side of the coil. and perhaps a battery isolation key.

 

Thanks for advise again!

 

Jon

[Guest salty_monk]

Hi Dan, where you been? Sleeping on the beach and smoking strange herbs?

 

Nah... Drew's been here, we've been taking on copious amounts of brown fluid, Mountain biking in the desert Bootleg Canyon got so dehydrated at 95 degrees we got the shakes (couldn't take water on fast enough!) then up to Vegas for a couple of days... exhibition to walk, trip to Spearmint Rhino's (lots of plastic modification there but easy on the eye...) lots of casino walking, no gambling to speak of then off to "The Drive" where we got to drive a Corvette, a Cadillac & A Solstice round a smallish track plus a Hummer on a pretty mad off road course.

 

Might stick some pics up when Drew downloads his camera...

 

 

Hiding a switch to give a constant earth to the negative side of the coil is easy and more effective than breaking the positive supply

 

 

That's what I meant...

[Mat-Moo]

It takes a flipping long time before that happens! and crimp connectors don't fall off? or the wire itself gets work hardened where it's crimped?

I'd sooner have soldered connectors any day over crimped ones. Crimped connectors only came in because of cost, quicker and cheaper.

Seconded!

 

http://cgi.ebay.co.uk/CAR-IMOBILISER-KIT-N...1QQcmdZViewItem

 

One downside of imobilisers is that they normally use some sort of key, this is all very well, however when you have your car keys, your likely to keep the two together.

 

This is pretty clever http://autospeed.drive.com.au/cms/A_0059/a...?popularArticle whole article is not there, but it's not complicated if you know anything about electronics. (found a copy of the article here http://www.kenarianz.com/index.php?name=PN...&t=429&start=0)

[Guest Battery Bill]

Dan

Nah... Drew's been here, we've been taking on copious amounts of brown fluid, Mountain biking in the desert

 

Ah! As Drew seems to be still alive, perhaps he just "forgot" to send us the "Pick up Pipe"

 

Please make him feel as guilty as possible

[Guest salty_monk]

nah what's his face told me you'd sorted it before he got around to sending it so told Drew not to bother... I guess you can pick up your DVD's in September!!!

[Jon Green]

Cheers matt,

 

Looks good, though i'll have to spend a bit more time working it out. Not an electronics wizard yet!

 

Jon

[Jon Green]

I've decided to make the immobiliser Mat pointed out at http://autospeed.drive.com.au/cms/A_0059/a...?popularArticle

 

I got an envolope throught the post this morning with all the components from Maplins. I've got a very small black box infront of me and I haven't got a clue! Its the DPDT relay and it's got eight legs and no wiring diagam to tell me which wires to put where. It's part number is N17AW.

 

If anyone is clever enough to enlighten me i'd be very grateful.

 

Cheers,

 

Jon

[Mat-Moo]

The info is cleverly hidden on the Maplin site http://www.maplin.co.uk/Media/PDFs/N17AW%20&%20N18AW.pdf

(Only by luck did I see the PDF doc icon in the top left!)