Early90 Posted October 10, 2014 Share Posted October 10, 2014 I am fitting a device to my friends Td5 110. The device is able to stop the vehicle by opening a circuit, via a relay , when sent a text message. I have fitted them to Tdi`s and the chosen circuit is pretty obvious! I was thinking of interrupting the supply to the fuel pump on the Td5 but am concerned the ecu may see a fault or even cause a problem elsewhere. Could anyone advise the sensible way of turning off a Td5 remotely with a single relay in a safe manner? Thanks John Quote Link to comment Share on other sites More sharing options...
Off Road Toad Posted October 13, 2014 Share Posted October 13, 2014 I'm pretty sure if you interupt the power supply to the fuel pump that it won't cause the MIL light to come on but will log a fault. I dont see this as being a problem, just clear the codes as and when. But i'm assuming this is intended as a last resort if a vehicle gets stolen? If so then it doesnt really matter if it throws a fault code anyway! And if its passive, then the vehicle wont be on and wont know any different. Steve Quote Link to comment Share on other sites More sharing options...
Early90 Posted October 13, 2014 Author Share Posted October 13, 2014 Yes, only as a last resort, although i will test it. Many thanks. Quote Link to comment Share on other sites More sharing options...
Dave W Posted October 13, 2014 Share Posted October 13, 2014 Look at the inertia switch under the bonnet, it is used to immobilise the engine in the case of a heavy impact so does so in a way that makes the vehicle "safe". It has two wires and you can put a relay in series with it on either side. Quote Link to comment Share on other sites More sharing options...
Ally V8 Posted October 13, 2014 Share Posted October 13, 2014 Seems like a lot of trouble to go to when the car already has an alarm/immobilisation ecu fitted,all you need to do is programme a couple of remotes to it. Quote Link to comment Share on other sites More sharing options...
Anderzander Posted October 13, 2014 Share Posted October 13, 2014 Is the inertia switch a normally closed contact or normally open ? Quote Link to comment Share on other sites More sharing options...
RedLineMike Posted October 13, 2014 Share Posted October 13, 2014 Inertia switch is closed contact as I have repurposed mine as an additional cut of switch Quote Link to comment Share on other sites More sharing options...
Dave W Posted October 13, 2014 Share Posted October 13, 2014 As above, normally closed Seems like a lot of trouble to go to when the car already has an alarm/immobilisation ecu fitted,all you need to do is programme a couple of remotes to it. The remote device he's referring to, I suspect, is one of the cellular gps trackers. Many of them have the ability to control a relay so you can send a text message to it and the engine dies. Quote Link to comment Share on other sites More sharing options...
Ally V8 Posted October 14, 2014 Share Posted October 14, 2014 Yes,I get that,but why would you need to do it when you leave the car you lock it anyway,the factory kit will already immobilise the engine ecu - far harder to get around than a cut out on a fuel pump relay.Plus many TD5's will run without the fuel pump going anyway. Quote Link to comment Share on other sites More sharing options...
Dave W Posted October 14, 2014 Share Posted October 14, 2014 Yes,I get that,but why would you need to do it when you leave the car you lock it anyway,the factory kit will already immobilise the engine ecu - far harder to get around than a cut out on a fuel pump relay.Plus many TD5's will run without the fuel pump going anyway. This is a Defender we're talking about, the immobiliser is very easy and quick to bypass and the door locks are barely worth the effort of using them. I suggest you do some more research if you genuinely believe that the factory alarm/immobiliser is going to protect a TD5 Defender. If you don't have a BBUS fitted then the alarm can be disabled in around 10 seconds. If they want to drive it away it takes a little longer but it still only takes a couple of minutes whichever of the recognised ways to bypass it they choose to go with. The BBUS makes a difference, especially if you move it into a more sensible location than the factory one. A TD5 will NOT run without the fuel pump running, they don't have a mechanical fuel pump and rely on a consistent fuel pressure at the regulator to run. The TD5 is more akin to an EFi V8 in it's fuel system than a 300TDi with the exception that the final injector pressure is produced mechanically by the cam. Quote Link to comment Share on other sites More sharing options...
Ally V8 Posted October 14, 2014 Share Posted October 14, 2014 Thank you for your suggestion,but I stand by the suggestions I have already made.All TD5 UK market Defenders are fitted with the Lucas 10AS alarm ecu.(Green box down behind the speedo) As indeed are current Puma engine ones.In base models they are set for non robust immobilisation and don't need keyfobs nor run a passive immobilisation ring around the ignition switch. If fobs are coded up to them using Testboook,Autologic or similar, they can be set to robust immobilisation.When they are set up like this the alarm ecu has to send a code to the engine ecu before it will boot up.For this to happen the alarm ecu needs a valid unlock signal from a remote fob,or an EKA input from the ignition switch.Without these the ecu will simply not work.I think you are confusing what TD5's are fitted with the earlier smart spider type immobiliser which simply disconnected up to 3 links. Trying to keep any thief out of a Defender is pretty much hopeless,but just disabling the fuel pump may not stop the car being nicked,I'm well aware that TD5's run an electric pump to give 4bar of fuel pressure,but as I said some will run with no pump.(I ought to know,I have diagnosed and replaced enough of them...) My own TD5 Disco will start and run with the relay out,although it is down on power. With the alarm ecu set to robust you put a very big hurdle in front of a thief,but persuading farmers to actually remove the key/fob from the car when unattended is a different matter. Quote Link to comment Share on other sites More sharing options...
Early90 Posted October 14, 2014 Author Share Posted October 14, 2014 That was an interesting read. This vehicle has two remote fobs and self immobilises after a few mins, i guess it is at its robust setting? I was not aware that Td5s had different features regarding the alarm immobiliser, this is the only one i`ve seen. As for why bother? It is just a handy, cheap level of security to add to whatever else one might do to keep their pride and joy. Plenty of Td5s get stolen so i think extras are worth it, hopefully never needed. I like the idea of the inertia switch, i will investigate. What is a BBUS ? a quick google revealed nothing. Thanks again Quote Link to comment Share on other sites More sharing options...
Dave W Posted October 14, 2014 Share Posted October 14, 2014 That was an interesting read. This vehicle has two remote fobs and self immobilises after a few mins, i guess it is at its robust setting? I was not aware that Td5s had different features regarding the alarm immobiliser, this is the only one i`ve seen. As for why bother? It is just a handy, cheap level of security to add to whatever else one might do to keep their pride and joy. Plenty of Td5s get stolen so i think extras are worth it, hopefully never needed. I like the idea of the inertia switch, i will investigate. What is a BBUS ? a quick google revealed nothing. Thanks again The reason TD5s are stolen and driven away under their own power is because the 10AS is a very weak immobiliser even in it's most robust configuration. It can be completely negated in a couple of minutes and ready to drive away by anyone who knows the TD5. It is particularly easy on the Defender, less so on a Disco 2 due to component positioning. You can completely defeat a 10AS on a Defender quietly in less then 5 seconds without actually entering the vehicle in any way but then you need to do some work to get it to drive afterwards so this is normally only used if they are stealing vehicle parts or using a transporter. The BBUS (Battery Backup Sounder) is a factory option for the 10AS. It relies on a feed from the 10AS to keep it quiet which means that if it's disconnected or the 10AS is powered down then it will sound an alarm using it's built in battery. The 10AS without a BBUS is VERY easy to disarm quietly in a number of ways without entering the vehicle/opening a door or bonnet. Fitting the BBUS in the standard factory position (behind the LHS headlamp) makes it easier to disarm so many people who do value their TD5 or TDCi move them somewhere less accessible. They are very easy to fit in the standard position as all the wiring is normally there already, moving them somewhere less accessible takes a little bit longer. Try a search for part number YWK100110 The best way of deterring thieves and keeping hold of your Defender is to use a layered approach, lots of different and preferably none standard deterrents work far better than a factory fit system that everyone knows how to defeat and can carry replacement components for (like carrying a spare unlocked 10AS to replace the "robust" one you have fitted). A combination of physical and electrical deterrents is also a good thing. The inertia switch and it's circuit is a good option in this case because it inhibits the main relay which will shut down the engine ECU and the fuel pump simultaneously. Quote Link to comment Share on other sites More sharing options...
Ally V8 Posted October 15, 2014 Share Posted October 15, 2014 As you say a layered approach is best in stopping theft,how you go about it is best done on an individual basis,so the thief wont know where to look. A couple of points though,whilst it may be easy to defeat a 10AS in terms of setting the alarm off,plugging in an unlocked one on a car set to robust will still not boot up the engine ecu - which has to see the correct coded signal form a 10AS. I suppose a thief could carry an engine ecu aswell as an alarm ecu,but thats all taking time to plug in etc.I guess most light fingered types would want to be away quickly - towing away is probably favourite. Also if you are relying on a BBUS to alert you,you might want to test it.The little ni-cad batteries in them dont last for ever and by now most TD5 ones will be old enough that they will be dead. Quote Link to comment Share on other sites More sharing options...
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