dougb Posted September 21, 2010 Share Posted September 21, 2010 Hi guys, I've just fitted an injection system to the Rover engine in my Stag, it was previously on carbs. I'm struggling with the wiring. The injection is a Lucas 4CU control unit. Can anyone help? Link to comment Share on other sites More sharing options...
Flying Farmer Posted September 21, 2010 Share Posted September 21, 2010 Very simple one this, There are 4 wires from the main engine loom that go to the car. Brown one is permanent live, white one is ignition live, red and white one goes to the red and white wire connected to the starter solenoid and the black and white one goes to the coil negativeThe hard part is stuffing the ecu and relays out of sight behind the dash!Neil Link to comment Share on other sites More sharing options...
StagNL Posted September 21, 2010 Share Posted September 21, 2010 Neil, trying to get my head around this for when the day I should get some injection kit to fit. By 'main engine loom' I take it you mean from the ecu itself?Is this Lucas 4CU thingy a standard (early?) Rover ECU? Or one from another engine/car type?Julian Link to comment Share on other sites More sharing options...
dougb Posted September 21, 2010 Author Share Posted September 21, 2010 Hi Neil do you know where the white wire goes to off the fuel cut off relay. On the ecu I have two large wires, one is brown the other is brown and white. Can I run the fuel pump off the old pump wiring? I'm not very good at wiring! Sorry. Link to comment Share on other sites More sharing options...
Flying Farmer Posted September 22, 2010 Share Posted September 22, 2010 The Lucas 4CU ecu is off the old rover vitesse (flap type), it may have been fitted to early injected V8 land rover/ range rovers too, but I am not sure about that.The fuel pump relay has purple and white wires that feed the pump, I think the white wires are part of the ignition live feed to the other relays.The main engine loom connects all the engine bay injection components and the ecu and has I think five wires that feed the main relays, one of these being the feed to the trip computer, this can be ignored.The fuel pump can be fed from the ignition live rather than the pump relay, but I have left all the relays in place, as the pump relay feeds other components in the injection.I do not have a brown and white wire on my loom. However, looking at the wiring diagram for the vitesse, the brown wire feeds directly to the main relay, and the white feeds first to the pump relay, then splits and feeds the main relay. Both these wires are significantly thicker than the rest,it may just be a different colour code from a different vehicleDo not be tempted to use the original stag fuel pump wiring as it is not up to the job (guess how I found this out), run a heavier gauge wire to the pump and make sure you have a big prefilter for the pump as the extra flow will hoover all the sh#t out of the bottom of your tank and block a small one PDQ, or destroy your pump if a filter is not fitted :(Neil Link to comment Share on other sites More sharing options...
shenderson Posted September 22, 2010 Share Posted September 22, 2010 Lucas 4CU is basically the same for Rover Vittesse/VDP and Range Rover EFI, but subtly different for the different applications. Same goes for the airflow meter, however best not to use a Range Rover AFM with Vittesse ECU, or vice versa. It will work, but not as well or as smoothly.This is a useful site: http://www.mez.co.uk/TuningTheRoverV8-pt9.html The SD1 owner's club has useful info too.The Stag fusebox has a couple of redundant fuse positions which are useful for getting power supplies inside the passenger's footwell.If you want to have a look, let me know, I'm in Birmingham.Steve H Link to comment Share on other sites More sharing options...
dougb Posted September 22, 2010 Author Share Posted September 22, 2010 Thanks for the help guys, I've got it to start and it ticks over well for a few seconds, then it cuts out and I have to restart it. I'm going to fit a larger filter tomorrow, see if that helps. Link to comment Share on other sites More sharing options...
Nick Jones Posted September 22, 2010 Share Posted September 22, 2010 Does the fuel pump keep running? Normally, the systems are arranged so that the pump runs for a couple of seconds when the ignition is switched on and then stops. It will then run again when the starter is engaged but there is usually some kind of fuel pump cut-off intended as a safety feature, to stop the pump if the engine isn't running. If, for some reason this system is not working correctly and the ECU doesn't recognise that the engine is running, or the relays are not correctly wired, the pump will stop as soon as the key is released from the starter position and the engine will only run until fuel pressure has gone - not long at all.Nick Link to comment Share on other sites More sharing options...
shenderson Posted September 23, 2010 Share Posted September 23, 2010 When the engine starts, incoming airflow moves the flap in the airflow meter, which closes a switch to provide power to hte fuel pump relay.You can test it by pushing the flap open with the ignition on, and listening for the fuel pump running.Steve H Link to comment Share on other sites More sharing options...
dougb Posted September 23, 2010 Author Share Posted September 23, 2010 thanks for the help got engine runnig boy it goes like stink better than the carbs Link to comment Share on other sites More sharing options...
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