2.5 TDI hot start problem

[DPM Dave]

I am having problems starting my 7 year old Discovery 2.5 TDI when it is hot.
It runs perfectly when started hot or cold. When cold it starts first time. I have found that if I lift the bonnet and leave for a few minutes it will often start first time.

I would be grateful for any ideas

[NeilB]

I am sure someone will be along in a minute who know about this but I would look at the fuel filter.

If you have too much moisture in the water trap then when you park it hot the water evaporates and on starting the fuel is too wet to work.

There used to be a tap on the bottom to drain the water out....but then my experience is with a Series III.

[DPM Dave]

Thanks for the reply. I will look into that.
One thing I perhaps should have mentioned initially is that the engine turns but makes no attempt to fire no matter how long you turn it over, but if I release the key leave it for a couple of seconds and try again it sometimes fires instantly. Once it has fired there is no misfiring at all.

Thanks again

DPM Dave

[JonS]

I have experienced something similar (cranking without firing) a couple of times in the last 12 months. It's been resolved by taking the key out, pressing the unlock button a couple of times and then having another go. Unscientific, but it worked.

I suspect my own problem is that the immobiliser has not been deactivated, - maybe I need a new keyfob battery.

However I believe there are some past threads dealing with intermittent immobiliser problems arising from problem solder joints. I suggest you do a search and compare symptoms!

Good luck

Jon

[NeilB]

OK, doesn't sound like water in the fuel as turning the key off and on again would make no difference. If it was a petrol engine I would have said the CPS but as you have a diesel then imobiliser sounds like a good bet. Either that or the ignition switch is not making all the correct contact when you turn it. You could try cranking the engine when warm and wiggling the key. If this works then an ignition switch it is.