V8 disco 1 has no spark

sierrafery said:

I've never said anything about problems with the EFI operation, all i did was to explain about what can be the reason of that missing feed to the coil

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I agree but you have high lighted the feed to the EFI ECU and feed fuel pump relay coil connection.
The issue is the feed to the coil via the immobiliser or whatever has taking its place, as it been replaced according to the OP.
I’m sure u know where the 12v feed up to the immobilise originates from. Repair/replace that feed and both issues the engine has will go sway.

discool said:

I agree but you have high lighted the feed to the EFI ECU and feed fuel pump relay coil connection.
The issue is the feed to the coil via the immobiliser or whatever has taking its place, as it been replaced according to the OP.
I’m sure u know where the 12v feed up to the immobilise originates from. Repair/replace that feed and both issues the engine has will go sway.

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I highlighted those two circuits cos my understanding based on the OP's statement was that there is power from F3 until HJ7 cos the pump is running without that direct wire from battery to coil also if there was no power on that red path with ignition on(without wire from baattery to coil) the EML should stay on due to missing power to the ECU and that was not revealed untill now so IMO the vehicle is not immobilised cos then would not be any power to F3 , the only problem here seems to be the missing feed to the coil

sierrafery said:

I highlighted those two circuits cos my understanding based on the OP's statement was that there is power from F3 until HJ7 cos the pump is running without that direct wire from battery to coil also if there was no power on that red path with ignition on(without wire from baattery to coil) the EML should stay on due to missing power to the ECU and that was not revealed untill now so IMO the vehicle is not immobilised cos then would not be any power to F3 , the only problem here seems to be the missing feed to the coil

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The main 10amp supply to the EFI ECU is not missing, its the control signal from the coil that is…

Perhaps there’s confusion with the initial running of pump to restore the fuel line pressure only.
It’s impossible for the fuel pump to continue running without the ECU receiving its signal to switch the pump relay, if u are an owner of a 3.9 or even a 3.5 engine you may know this, and you have any practical knowledge of the disco engine that is.

Also its a shame but it appears the Forum idiot who knows f all therefor so doesn’t have a clue and then agrees with your post.

as the immobilizer has been removed check your grounds as the unit removes some of these grounds when working

mystery said:

as the immobilizer has been removed check your grounds as the unit removes some of these grounds when working

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As your wiring diagram with the header Defender1 shows the immobiliser controlling the fuel pump relay, it isn’t correct for a Discovery 1 3.9. Plus the fuel pump doesn’t have any relationship with the immobiliser .

Is the diagram a cut&past from the Defender LR workshop manual?