Weird starting problem TD4

Went to the car earlier and it wouldn't start even though turning over well, I then realised the low pressure fuel pump wasn't running, every time I turned the ignition on there was no fuel pump.

Anyway, as I sat pondering the situation I flicked the air con switch to off (fan was already off so it wasn't "fully" on) and as soon as I turned the ignition back on the LP fuel pump was running again. Needless to say she fired straight up.

Since then she's started regardless off the air con being on or off.

Any ideas what the issue night be here?

Also, how noisy (or quiet) should the fuel pump be? I can hear it with the engine idling.


Cheers

Sounds to me like just a low charge on the battery. AC uses quite a lot of juice. After turning the AC off there was enough power to run the pump and allow starting - then the battery got charged after running for a while.

Maybe check the battery condition (is it old), or the alternator. Could also happen if lots of short runs which don't give enough charge, particularly on an old battery.

Doesn't sound like anything sinister.

I did have to jump start it 2 weeks ago. I tested the alternator at the time and it was putting out 14.4v. I wonder if it's a CCA drop on the battery although it's started ever since.

I've no idea how old the battery is as it came with the car, no dates engraved on the battery like the old days.

14.4 volts sounds ok to me for an alternator. If you needed to jump start a couple of weeks ago this suggests old or weak battery.

If you are doing short/stop start journeys with the AC on from go then battery may not be charging enough.

Could also be your LP pump starting to fail. If it does it again give it a thump and see if that gets it turning.

Could be time for a new pump. Don't bother with a cheap one - get a decent one or genuine.