Cobra Immobiliser Fault

[Harve]

Hi all,

I've recently returned from Honeymoon and found that the Stag felt neglected so refuses to start now.

The day before I left for holidaythe immobiliser stopped functioning and would not arm itself meaining I no longer needed to turn it off which was fine by me as its annoying. However after leaving it for 3 weeks it seems to have drained the battery. At least I hope its that rather than any other electrical fault as I cant stand electrical work.

So does anyone know much about immobilisers, specifically how to remove them without wrecking the ignition circuit? NowI know immobilisers weren't a standard fit to the stag so I'm guessingthat there might not be too many people on here with knowledge of them but I thought it worth a go.

Its a Cobraimmobiliser, no idea what model etc. I've read that they cut into the fuel pump and ignition circuit, is it just a case of joining the affected circuits back up once the cobra box is removed?

Cheers

Harve

[KOY 23]

imported post

Harve.

If it is a decent immobiliser it should have black unmarked wires and 2 or 3 outputs to isolate starter, ignition, fuel pump, take your pick. If you remove it, there may be insurance issues, as well as the lack of security but that's your call.

If you want to remove it, disconnect the black battery terminal, find the Cobra box, there will be about 10 wires coming out of it. There will be a pair of wires to each circuit being isolated, follow them to where they join the Stag's wiring, note the colour of the car's wiring, Join the two with the same colour code together. It is important that these joints are 100%, ideally the joints should be soldered and insulated with heat shrink sleeving. Please no scotchlocks!!
Temporarily reconnect the battery and see if the car starts. If so disconnect the battery and disconnect all the other wires from the box, trace where they join the car's loom, cut and insulate. In addition to the immobilised circuits, there should be permament 12v, ignition controlled 12v, earth(maybe 2) and wires going to whatever you use to deactivate the immobiliser.

If it has been properly installed the wiring should be hidden and the immobiliser cuts made at different parts of the loom so it is not obvious what connects where

I must stress that you need to check what is involved before you remove anything, to make sure you are confident doing it.

Good luck.

John.

[Arbman Al]

imported post

Harve wrote:

Hi all,

I've recently returned from Honeymoon and found that the Stag felt neglected so refuses to start now.

The day before I left for holidaythe immobiliser stopped functioning and would not arm itself meaining I no longer needed to turn it off which was fine by me as its annoying. However after leaving it for 3 weeks it seems to have drained the battery. At least I hope its that rather than any other electrical fault as I cant stand electrical work.

So does anyone know much about immobilisers, specifically how to remove them without wrecking the ignition circuit? NowI know immobilisers weren't a standard fit to the stag so I'm guessingthat there might not be too many people on here with knowledge of them but I thought it worth a go.

Its a Cobraimmobiliser, no idea what model etc. I've read that they cut into the fuel pump and ignition circuit, is it just a case of joining the affected circuits back up once the cobra box is removed?

Cheers

Harve

Hi Harve,

Don't know about the Cobra systems but:

CONGRATULATIONS !!

[robertt1948]

imported post

Hi Harve,

I may be wrong but I believe the requirement for an immobiliser to be fitted for the Club insurance has been lifted recently.

Robert

[GDPR]

imported post

I have a Cobra - if you know what model I have the paperwork that came with it mines a 7928/26/HF

[Harve]

imported post

Cheers for the congratulations arbman101!

I never told my insurance company about the cobra system as the cardidn't come with any of the certificates etc to show that its thatchcam approved or anything. Plus its mainly parked in a locked garage under the house.

I'll have a look for model number etc. If its anything like the rest of the work thats been done to the car in the past it wont be the highest quality install so shouldn't be too difficult. If it turns out to be too tough I might just buy a replacement box.

Cheers