I’ve sent the below to Emerald to see if they have any ideas but some of you may have a clue:
I just received your ECU for my Lotus Exige and installed it last night (now with some serious back pain ) and everything was fine, it was running lovely!
So I then went to tidy up all the loom and get it all mounted properly but accidentally snipped the Orange / Purple (Fuel pump relay), I continued to move some of the wiring about then scotch clipped the snipped Orange / Purple wire together� Unfortunately after this the fuel pump doesn�t arm for the 2 seconds once you turn the ignition on.
I�ve checked the connector going to the fuel pump and there�s no voltage along the live so it seems that �something� I�ve done has disturbed all this L I�m fairly sure I can�t hear the relays click when I turn the ignition on so I may have blown them up� Is this feasible? Also I�ve checked the fuses and they were all OK.
Any ideas would be greatly appreciated before I head home tonight and have another go
So any thought of where to check first would be great… I just warmed it up on the drive way last night and it sounded “proper”! A nice bark when I blipped the throttle
So I was looking forward to a proper blat but alas it all went wrong at the last hurdle!!! sob sob
I didn’t need to do anything first time with the immobiliser… Will I need to set that up? The engine turns but with no fuel pressure it ain’t never gonna fire…
I though even when immobilised the pump still fired up, the immobliser only affected the cranking / ign. / inj. circuits? (the service manual says cranking and running circuits)
So I then went to tidy up all the loom and get it all mounted properly but accidentally snipped the Orange / Purple (Fuel pump relay), I continued to move some of the wiring about then scotch clipped the snipped Orange / Purple wire together� Unfortunately after this the fuel pump doesn�t arm for the 2 seconds once you turn the ignition on.
The orange/purple wire is the fuel pump relay control connection to the ECU. The other side of the relay’s coil winding should be connected to the white wire (ignition controlled +12v) so all the ECU has to do is earth the orange/purple wire to switch the fuel pump relay which in turn powers up the fuel pump.
As the engine was running before cutting the orange/purple wire it may be that the wire is not rejoined probably. The scotch lock or crimp you’ve used may not actually be making contact - it’s possible that the terminal is crimped onto the insulation and not making contact with the wire itself (been there done that!).
Just to confirm, switch the ignition on and listen for the relays. The fuel pump relay should switch when you key on (another one of those relays will also switch at the same time so you won’t know which is which) but after approx 4-5 seconds the relay should switch off again. Listen for the relay switching off - if you don’t hear this click after 4-5 seconds then it’s most likely that the crimp terminal is at fault.
I�ve checked the connector going to the fuel pump and there�s no voltage along the live so it seems that �something� I�ve done has disturbed all this L I�m fairly sure I can�t hear the relays click when I turn the ignition on so I may have blown them up� Is this feasible? Also I�ve checked the fuses and they were all OK.
I think you may be hearing the main relay switch rather than the fuel pump relay. There is a 20amp fuse for the fuel pump which may have blown but there is no reason for that to have happened.
I don’t think there is anything you can do to blow up either the fuel pump relay or the ECU. Shorting the orange/purple wire to earth won’t cause a problem (it’s what the ECU does to switch the relay). Shorting a +12v to the orange/purple wire won’t harm the relay and the ECU’s fuel pump relay driver will shut down to protect itself from the over load condition.
The only thing that makes sense is that the connection between the ECU’s pin 20 and the orange/purple wire terminal at the relay is broken.
Hopefully it’s just this easy fix and you can be up and running again!