The earth terminals look fine, I'll drop them off and clean them up just to make sure, good call. I do get the voltage at those terminals but I am aware that, as you have to disconnect the plug coupler there is no current draw so it won't necessarily reflect any volt drop over a high resistance contact. I am going to put some sort of shunt over my meter to get a better idea of real world voltages on those pins. I am considering taking the OVP out and bypassing the contacts in it, what can go wrong with that!!??
I'm not even getting to that stage, the fuel pump does not even prime the system prior to start. Unless the ECU does some sort of health check on the sensors prior to picking the fuel pump relay I cannot see how they are the cause. I'll check their impedance to see if they are in spec just in case.
I have checked both parts of the OVP by checking the voltages on the (disconnected) ECU plug couplers and got both of the voltages I would expect, I'm aware that this may not show any volt drop over a high resistance contact in the OVP though as it wouldn't be pulling any current. I made a couple of straps up last night and I'm going to strap out the two contacts on the OVP and see if the fuel pump relay picks when I turn the ignition on (I'll try to resist trying to start it.) That should prove once and for all if its the OVP. I opened up the OVP to see if I could clean the relay contacts but mine (K.A.E) has sealed relays rather than the open ones I have seen before.
Thanks for that, 8v should have done it I guess. I'll pull the relay and measure the coil resistance. I'll also try it with one of the radiator fan relays which has the same part number.
I'll see what I can do but the access to the bottom of the OVP relay base is really difficult to get meter leads into. I shorted out pins 1&2 and 4&6 yesterday which should replicate a good OVP and that didn't help.
This is pin 5/6 on the other plug coupler, the body wiring side rather than the engine loom.
It is green, it is shown as being a loop terminated on pins 5&6. I would have expected virtually a short circuit but it has a resistance of 247ohms. Can't see it being relevant but just wondered why they would have put an external strap in the loom.
Different markets had options that we dont, it's probably an interlock circuit for another system.
Probably right, unlikely to be causing my problem.
