Thread: Disco V8 won't start for the first time ever - Help

That's right no fuel pump prime and no spark.

I'll be studying the electrical drawings today and see what they have in common.

And I do believe the M & S light were the battery getting low as schuy said. Its now been charged.

And the fuel gauge is working Dan.

Thanks for the input guys I'll have the Multimeter out this afternoon. Wish me luck.

Check fuse 20 in engine fusebox. It powers ignition barrel exciter thingo, which in turn allows your key fob to send signal to BCU to start engine.

Well I had the multi meter out last night and have come to the conclusion that it MUST be the Crank Position Sensor. The spare I had that came off a running engine must have failed while it's been sitting in the spares box.

When cranking the engine I'm not reading any voltage induced by the sensor. I don't have an oscilloscope at home to test the frequency or magnitude the sensor so I've got a Bosch one on order and I'll have another go when it arrives.

The fuel pump has me a little perplexed. Would you think if the engine has been cranked and the fuel pressure is already up would the pump still run when the ignition is on? Or would it not have to run as it already has pressure?

Thanks Ballbag fuse 20 is ok.

Originally Posted by FisherX

The fuel pump has me a little perplexed. Would you think if the engine has been cranked and the fuel pressure is already up would the pump still run when the ignition is on? Or would it not have to run as it already has pressure?

Thanks Ballbag fuse 20 is ok.

Not if the CPS is cactus

All good now, BUT.

So the new CPS arrived and a quick 5min later it was fitted. Cranked the engine over and expected it to fire straight up. It didn't! So I walked away in disgust, had a smoke and just a little cry.

After calming down I went and had another look. I unplugged all the connections on the ECU to make sure all was good and everything looked fine. Plugged it all back in and tried to start it again. I didn't hold out much hope and was thinking I'd have to check the continuity of each of the sensor wires.

But she fired straight up!

Another BUT, is that did both my CPS fail OR did the ECU just need a reboot? I could try and fit each of my old CPS and test but I can't be bothered at the moment. Maybe another day.

Thanks all for your help