Somethings changed - but why?

[holmbush]

Some small pleasures are often the best - like listening to the fuel pump prime when you press the tit on the immobiliser fob. Except this does not seem to happen any more! Something has changed but I don't know why. Activating the immobiliser now energises the ignition and the car starts and runs perfectly but the fuel pump does not appear to prime on start up - can any techies out there offer an explanation? Is trouble afoot? Why should this suddenly occur? Do I need to get the alarm/immobiliser checked out? Your comments would be welcome.

[chris52]

Its likley to be one of the solanoids, if I remember correctly there is one just for the initial priming of the pump. I am sure someone will be along soon to confirm this though

Chris

[steve-V8s]

chris52 said:

Its likley to be one of the solanoids, if I remember correctly there is one just for the initial priming of the pump. I am sure someone will be along soon to confirm this though

Chris

I don’t think that is the case. The fuel pump relay is normally driven from a pin on the ECU. When you turn the ECU on it drives the Fuel pump relay for a few seconds and then turns it off again until the engine is started. If you lock and then unlock the car and within a few seconds turn the ignition on does the pump prime as you expect ?

[spend]

I can't really follow your sequence, but..

The immobilizer is a 'defeat' mechanism??? It shouldn't switch anything on - only apparently if they were already switched on but the immob was cutting them off and then you press the remote.

[WOO5IE]

Could a short or stuck fuel pump relay cause this so that the pump is permanently primed.

Maybe complete boxxocks though

[holmbush]

Sorry, my explanation of events was a bit misleading. My usual sequence of events is to unlock the car, place the ignition key in the lock and then turn the ignition on. This brings on the warning lights - I then have to press the tit on the immobiliser fob to de-activate the immobiliser which allows the car to start. It was at this stage that the fuel pump used to prime. It no longer does that although the car starts and runs fine. If I turn the key without first pressing the tit on the fob, the starter works but the engine will not fire. Is that any clearer?

[steve-V8s]

WOO5IE said:

Could a short or stuck fuel pump relay cause this so that the pump is permanently primed.

Maybe complete boxxocks though

Good call that.