JP Posted March 26, 2002 Share Posted March 26, 2002 Just had big red key fitted. Does anyone know if the ECU / immobiliser suffers from repeated disconnection of the battery? Car is a 1.6KSS. The engine is obviously rough when first started after the switch has been off. I thought it would serve as an additional theft deterrent, but am now concerned about disconnecting all the time. I also don't like leaving it in, in case someone decides to nick the key! Help! James. Link to comment Share on other sites More sharing options...
mikehoile Posted March 26, 2002 Share Posted March 26, 2002 Hi James. I had one fitted recently due to impending Curborough. No problems to date except the immobiliser needs resetting on the key fob. Regarding the ECU I look forward to comments on this one. I bought a spare key in case I got stuck and try to carry it separately. I think it must be an added security measure and try to remember to take the key out when leaving the car. Link to comment Share on other sites More sharing options...
tony isherwood Posted March 26, 2002 Share Posted March 26, 2002 my BRSwitch has a live circuit that maintains the ecu and immobilser. (I think !) Certainly the immobiliser until it packed up. Link to comment Share on other sites More sharing options...
murph7355 Posted March 26, 2002 Share Posted March 26, 2002 What age is the car? And what sort of immob' key do you have? The engine shouldn't be any rougher after using the key than it is normally. So if it I'd suggest there's something else amiss. I use mine all the time to help with security and with preventing the battery going flat and it's always been fine. Link to comment Share on other sites More sharing options...
JP Posted March 27, 2002 Author Share Posted March 27, 2002 Andy, Car is a '99 - probably EU2. It definitely sounds rough on start after battery disconnected, but only for 10-20 seconds. After that it runs beautifully. Car has the standard rover immobiliser for the K series. James. Link to comment Share on other sites More sharing options...
murph7355 Posted March 27, 2002 Share Posted March 27, 2002 If it were mine I'd get Caterham or an agent to have a look. This is partly because I'm mechanically incompetent, but also because it doesn't sound right. I've not heard of anyone saying their immobilised, battery cut off equipped cars sound rough after having the switch taken off, so assume that the ECU/immob' combo is fine (I'd expect it not to start at all if it were upset with being disconnected). In what way does it sound rough? Maybe there's something amiss/loose with the wiring somewhere (at the battery cut off switch?) that's causing it? Have you tried another key (as a simple check). Link to comment Share on other sites More sharing options...
tony isherwood Posted March 27, 2002 Share Posted March 27, 2002 My immobiliser was an aftermarket fit as the original had been done away with. It was fitted to cut out ignition and stop fuel pump. Afraid I cannot remember the make. I have never had problems with rough running / starting, I use the red cutout key as my "key", I have a toggle switch on the dash board for ign on /off and a big rubbery button to start the engine. No big red buttons availiable at the time I suppose ! Link to comment Share on other sites More sharing options...
tony isherwood Posted March 27, 2002 Share Posted March 27, 2002 Just a thought ! Does the car sound rough it the car is left with key in the on position for a while ?, Have you had a service ? it may be rattley tappets before the oil gets to them (Oil change / Filter change with faulty flow back ?) and just coincidental to the fitting of the BRSwitch ? Link to comment Share on other sites More sharing options...
Peter Carmichael Posted March 27, 2002 Share Posted March 27, 2002 Check/replace your spark plugs. Just a hunch. Link to comment Share on other sites More sharing options...
danwhiley Posted March 27, 2002 Share Posted March 27, 2002 I've heard of other people who drill a small hole in the "eyebrow" cover and then put chain & padlock the key to the cover to stop it being nicked by some amusing prankster. I must admit to leaving mine in as it's a royal pain in the rear to have to re-set the immobiliser every time (mainly 'cuz I haven't worked out the quick way to do it and spend five minutes fiddling with the key fob and ignition switch) Dan. Link to comment Share on other sites More sharing options...
tbhall777 Posted March 27, 2002 Share Posted March 27, 2002 On the back of the standard FIA approved master, there are 2 auxiliary switches. One breaks connection when switch is closed and the other makes and visa versa when switch is opened i.e. off and take key out. Standard they are wired so that switching off disconnects supply to the ECU. The other aux switch connects the protection resistor to the alternator output, to prevent damage as engine spins down if the master switch is turned off with the engine running. On my installation, I have bridged the switch which supplies the ECU so that it always has supply regardless. You could just join the wires together, but having a bridge with blade connectors means you can quickly remove it when in competition; as it is a legal requirement that if the master is turned off, the battery is totally disconnected from the cars electrics. If power is disconnected from the ECU, it will loose it's map and will have to learn all over again. That is why your car runs like a dog every time you turn your master off. This only applies to the O.E.M Rover ECU's. After market ECU's in almost all cases do not work like the MEM's for instance. They will have a lookup table in ROM, which is non volatile. For road use bridge the switch. Also if the Rover ECU is kept supplied as I have stated, it will flatten the battery in a few days as the immobiliser sucks quite a few milliamps. Link to comment Share on other sites More sharing options...
JP Posted March 27, 2002 Author Share Posted March 27, 2002 tbhall777, Cheers. Sounds like you've hit the nail on the head in para 4. It was fitted at my last service last week by Midway Motors. Mike warned me that it would run rough briefly, although today it was fine! The immobiliser just seems to need few (random) presses of the on / off buttons on the key fob to disengage. Is there a proper way to reset it? I'm just concerned that the ECU having to "relearn" every time is bad for it. Link to comment Share on other sites More sharing options...
tbhall777 Posted March 27, 2002 Share Posted March 27, 2002 It may take a long time for the ECU to learn and make subtle changes over time. I may be wrong. But I think you should not destroy the map that may have taken a long time to form fully. keep it powered and buy a battery conditioner type charger that can be permanently connected. There is a correct sequence to re-enable the immobiliser depending on whether it lost power with the immobiliser on or off. I am at work at the mo and dont have access to the info for reseting. Call caterham to find out or maybe someone else will be along in a moment. Cheers. Link to comment Share on other sites More sharing options...
Julian Thompson Posted March 27, 2002 Share Posted March 27, 2002 Personally my idea on cutoffs is to fit a 1 amp fused link between the cutoff switch terminals. This keeps everything connected to stop the constant rebooting all the time but clearly only 1A of current handling. This would work really well. You'd have to remember that if you accidentally hit a switch or whatever without the cutoff handle in you'd blow the 1A fuse and necessitate a reboot anyway! Link to comment Share on other sites More sharing options...
JP Posted March 27, 2002 Author Share Posted March 27, 2002 Maybe all this agro is something telling me it's time to get the Emerald ECU I've wanted for a while. Link to comment Share on other sites More sharing options...
murph7355 Posted March 28, 2002 Share Posted March 28, 2002 If the ECU lost its map, how would the engine run at all? There must be some base parameters in there? Or is it fine tuning (closed loop?) that goes hence the roughness? Link to comment Share on other sites More sharing options...
JP Posted May 1, 2002 Author Share Posted May 1, 2002 Julian, I've finally found time to fit a bypass 1A fused wire. Went out to the car today, removed the cover, naively expecting to find a switch with one cable in and one cable out. Unfortunately, there are the 2 big cables from battery etc. and two pairs of smaller cables. Do you just need to bridge the 2 fat cables or are there 3 switches here working independently that all need bridging?? Help, James. Link to comment Share on other sites More sharing options...
JP Posted May 6, 2002 Author Share Posted May 6, 2002 Back to the top - any help please? Link to comment Share on other sites More sharing options...
Chelspeed Posted May 7, 2002 Share Posted May 7, 2002 Don't bridge them all, two of the minor contacts are normally open and closed when you turn the red switch off. Bridging them could cause a bit of a disaster. If your ecu is supplied just off the normal wiring then you need to just bridge the two largest terminals with the 1A fuse. If your wiring uses one of the smaller contacts to also switch the ecu then you need to bridge from the battery (incoming) side of the larger contacts to the ecu side of the smaller contacts. Start with the former if the ecu still loses power when the switch is off try the latter. But better yet get someone who knows an amp from a volt to look at your car first, diagnosing over the list is fraught with difficulties.... Link to comment Share on other sites More sharing options...
Nick M Posted May 7, 2002 Share Posted May 7, 2002 Having spent most of yesterday playing with a battery master switch, I can concur with what Graham is saying. When the switch is "off", i.e. open, on of the pair of spade connectors makes a switch - this is to protect the other electrics from run on, i.e. when the engine is running and the switch is flicked the alternator is still charging and the little bypass wire from the alternator side to the spade terminal then allows the alternator charge to go to earth rather than zapping the electrics. When the main isolator key is switched to "on", the main batter circuit is made and the other pair of spade connectors becomes live, but the other ones then go dead. This is the circuit from which all the car's electrics are operated. In effect, turning the battery isolator on is like turning your ignition key to position 2. If you want to have some items remaining off then you need to take a feed to an ignition switch and then have some "switched" circuits the other side, e.g. the ECU, fuel pump, etc. This is probably a pretty crappy explanation, but it may be of some help. Link to comment Share on other sites More sharing options...
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