Alternatives to starter kill for aftermarket alarm

[javelin401]

Maybe I'm out on a limb a bit as not seeing old posts for alarms but anyway, finishing up wiring in the control on my 98 4.0, and I prefer to steer clear of a starter kill as hot wiring the starter is cake on these. I've made all the other connections at or near the junct block and the system works great with way better fob range than the OEM transmitter for keyless entry.

Ive used the FSM to carefully get this far and would love to kill the fuel delivery(with a relay) but that appears too invasive, punching wiring thru the firewall and hacking into the power dist module harness. Anyone have experience on this? One alt idea would be to defeat the shifter solenoid which would lock it in park in system armed mode. This looks doable at the junct block.

I'd be glad to share what I've documented if anyone wants info on adding or upgrading a security system.

thanks!

 

[lawsoncl]

One alt idea would be to defeat the shifter solenoid which would lock it in park in system armed mode.

That's a cool idea! It take the average thief a few minutes to figure that out. They'd have to pull the the bezel and push the interlock down to get it to shift out of park.

 

[tech1001]

I would kill the auto shutdown relay

 

[javelin401]

Anything to slow the thief down improves your chances of deterrence.

I was looking into the auto shutdown relay but there's no real theory of operation on this in the FSM. I'll go back thru the schematics but it didn't look like it could be easily done from the Junct block. I prefer not hacking into things where possible. If it was based off of a factory alarm condition that would be good but I think it's triggered by the PCM under certain conditions?

thanks for the replies!

 

[8Mud]

The dark green/orange wire near the firewall where it goes down the fuel injector harness. Common power for all the injectors. More than one way to shut off the fuel.
That said I woke up one morning and caught some guy trying to load my wife's XJ onto his truck with a crane lift. A tip alarm makes more sense to me. You should have seen his face when I walked up with my shotgun. He took off with the boom over the side of the truck just clearing a whole row of parked cars.

 

[javelin401]

Ha good to know US isn't the only place that guns exist. Yeah my system does have a 'shock' sensor. That said I need to find out if it will trip if jacked up.
Anyway on the fuel shutoff - all good, I intercepted the brown lead with the NC alarm relay contacts from the fuel pump relay coil off the PDM. When armed the fuel pump is dead.

thanks all!

 

[Anak]

I would be interested in the details. PM me if you don't want to post them publicly. I know I wouldn't want to make them public.

 

[Vince]

Electric Parking Brake calipers (EPB). They could be wired to the alarm output to latch on, overriding whatever cabin switch you put in for regular use. A separate key switch could be hidden to release the latch so even if the battery is disconnected, the parking brakes would stay clamped. Would need a circuit that incorporates a latch relay.

They can also be wired independently to turn an open diff into a manually operated brake lock differential. Would also be good for a TrueTrac to control slippage.