boringol Posted March 10, 2014 Share Posted March 10, 2014 Hi I am looking at megasquirting my V8 disco however after looking at the wiring loom there is no large plug to disconnect from the engine harness from the rest. Traced back into the drivers foot well takes it to the ECU but with several branch offs leading under the dash. I suspect one goes to the "spider" immobiliser and the other the alarm/central locking. Have looked at RAVE electrical diag but not finding it very clear. If anyone has done this I would appreciate some advice Thanks Nigel Quote Link to comment Share on other sites More sharing options...
AncientGeek Posted March 12, 2014 Share Posted March 12, 2014 Is this a 300 series 3.9 Disco? As I remember there is a big white connector under the dash that connects just about everything coming from the engine bay. The spider wiring is a pain but after ripping out the spider and its wiring completely it was clear what goes to what. The thin wires going to the spider can just be cut off, the thick wires you must work out which is which (they are helpfully all black). I also remember RAVE was not much help. Also ask yourself if its really necessary. If your wiring is good, leave it there and just add the few extra wires you need. You can re-purpose some of the MAF and stepper motor wires. Then cut off (or splice into) the wires on your current ecu connector. Could save a lot of work. Quote Link to comment Share on other sites More sharing options...
FridgeFreezer Posted March 12, 2014 Share Posted March 12, 2014 Also ask yourself if its really necessary. If your wiring is good, leave it there and just add the few extra wires you need. You can re-purpose some of the MAF and stepper motor wires. Then cut off (or splice into) the wires on your current ecu connector. Could save a lot of work. Re-using the loom in-situ is a bit of a headache to trace all the wires out but ultimately with a hotwire loom it works OK and you have enough spare wires from things like the stepper motor that you can re-use for other things. Just be sure to buzz things out with a multimeter, Lucas re-use wiring colours, from memory there are at least two wires with the same colour/stripe combo! Quote Link to comment Share on other sites More sharing options...
FridgeFreezer Posted March 12, 2014 Share Posted March 12, 2014 As TSD has just pointed out, there is an alternative... Quote Link to comment Share on other sites More sharing options...
Hybrid_From_Hell Posted March 12, 2014 Share Posted March 12, 2014 ^^^^^^ duly nicked for website Quote Link to comment Share on other sites More sharing options...
boringol Posted March 12, 2014 Author Share Posted March 12, 2014 I suspect I will have to go delving deeper into the dash. Found the spider wires and yes they are all black. Do you know if there is also a connection to the green alarm/central locking box in the passenger footwell? Cheers Nigel Quote Link to comment Share on other sites More sharing options...
zardos Posted March 13, 2014 Share Posted March 13, 2014 Luckily when converting my Disco 3.9 V8 to Megasquirt there was not a wire left (well actual no disco body shell at all ), so I did not have this problemHad to do all new wiring and plumbing I do have a complete engine loom without any cut wires so it should be possible just to disconnect everything Quote Link to comment Share on other sites More sharing options...
Cynic-al Posted March 13, 2014 Share Posted March 13, 2014 I reused a lot of my old loom (I admit on an older car) and have had the odd problem due to blacking in the wire, if I was doing it again I would start from scratch and use all new. Quote Link to comment Share on other sites More sharing options...
Chazza Posted March 13, 2014 Share Posted March 13, 2014 So if the Rover ECU is chucked out, MS can take over all of the chores? Quote Link to comment Share on other sites More sharing options...
Cynic-al Posted March 13, 2014 Share Posted March 13, 2014 It can do everything engine related. I guess you could do more with custom work to it? Quote Link to comment Share on other sites More sharing options...
FridgeFreezer Posted March 13, 2014 Share Posted March 13, 2014 So if the Rover ECU is chucked out, MS can take over all of the chores? What are all the chores? Quote Link to comment Share on other sites More sharing options...
Chazza Posted March 13, 2014 Share Posted March 13, 2014 What are all the chores? Not sure - that is why I asked? Quote Link to comment Share on other sites More sharing options...
FridgeFreezer Posted March 14, 2014 Share Posted March 14, 2014 Well, what are you expecting it to do or not do? Quote Link to comment Share on other sites More sharing options...
Chazza Posted March 14, 2014 Share Posted March 14, 2014 Well, what are you expecting it to do or not do? I think you misunderstand me. My question relates to what the Rover ECU has to do. When I fit the MS, is there something that the Rover ECU does which the MS cannot? Or is it a case of the MS completely replacing every function of the Rover ECU, Cheers Charlie Quote Link to comment Share on other sites More sharing options...
Bowie69 Posted March 14, 2014 Share Posted March 14, 2014 It's a complete EFI system, so does do everything, maybe slightly differently, but still everything. You can literally take a hacksaw to the ECU loom. Quote Link to comment Share on other sites More sharing options...
Cynic-al Posted March 15, 2014 Share Posted March 15, 2014 You just need to remember it doesn't use all the same sensors and actuators as the existing system so you will need to alter the wiring and some of the engine bits. Quote Link to comment Share on other sites More sharing options...
Chazza Posted March 15, 2014 Share Posted March 15, 2014 Thank you Quote Link to comment Share on other sites More sharing options...
boringol Posted October 29, 2014 Author Share Posted October 29, 2014 Thanks guys All done and it stared first time Quote Link to comment Share on other sites More sharing options...
Bojerne Posted November 9, 2014 Share Posted November 9, 2014 I wouldn't put a hacksaw to the loom - why not reuse all the wiring and add a few extra for the ignition ? Phil Ringwood/Shaun makes a MSII that re-uses the wiring, if you don't wnat to fiddle with it yourself Quote Link to comment Share on other sites More sharing options...
FridgeFreezer Posted November 10, 2014 Share Posted November 10, 2014 I wouldn't put a hacksaw to the loom I did because it's the easiest way to get the big connector off, I reused the flapper loom & added wires as needed. Done similar on Hotwire installs, they have more than enough spare wires already. That said, I reckon it's as much work and messier to re-use an old Rover loom than to make a shiny new one with everything where it should be, as most old Rover looms are going brittle or the connector boots are splitting or there's mud in them, etc. etc. Quote Link to comment Share on other sites More sharing options...
Cynic-al Posted November 10, 2014 Share Posted November 10, 2014 I used my old loom and a lot of the cables had negative blacking (don't know the technical term but you get it a lot on boats), this makes them impossible to solder, conduct poorly and eventually they just break. I did it to save cost really but 4 years on I wish I had just used new cable and connectors as I have had a couple of injector plugs fail. I've had in intermittent fault for the last few months where the power goes off for a split second then comes back on. If your driving the engine can usually pick up and carry on but at idle it caused a stall. I was convinced it was ignition related and I had bit of wire all over shorting different things trying to find the fault. A couple of weekends ago it finally got bad enough that I could trace it and it turned out to be a fuse where the legs had turned to powder, it just fell off when I probed it. Most annoying thing is I put the fuse box on the roof as I thought it'd be dry! Stupid electrics! Quote Link to comment Share on other sites More sharing options...
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