3.9 Series1 Discovery Stalling When Hot

UPDATE:22/12/2012

OK, so after changing the coil, ignition module and Water Temp Sender/Sensor and no joy, I decided, as a last ditch measure, to change the fuel pump/sender. If that didn't work I was faced with either flogging it as scrap/non-runner for breaking, or taking it to a garage and hoping they could fix it for a reasonable cost.

So last night I put in an aftermarket pump/sender. As soon as I touched the pipe fittings with a spanner to try and get the nuts and olive off, the pipes coming out of the sender disintegrated. The way they crumbled away it was obvious that they must have been completely perforated. Rather surprisingly there was absolutely no fuel at all in either of the pipes going to or from the tank. Like they were completely dry.

After getting the old unit out and the new unit in I tried to start it.

If caught for a split second, then died. I thought that was the end of it.

I kept turning it over with nothing happening at all. As a very last attempt to get it going, I pulled the dizzy cap off, sprayed the inside of the cap and the arm and points with a good dose of WD-40. Tried it again and it fired first time and ran sweet as a nut!

I left it running for over an hour on the drive last night and it ran smooth as silk.

Left it overnight, it started first time this morning and I've done about 120 miles in it today with zero problems. No cutting out. No stalling. No spluttering. Absolutely perfect.

I am not sure why it needed WD-40 in the dizzy. I have never done this before. I am wondering if it got wet in there when the cap was off when I changed the water temp sensor. I didn't drain the system first before I pulled the sensor out (bad me!). Or if the aftermarket cap is actually no good. I think I'll replace it with an Original Landrover one ASAP as I have heard that the aftermarket ones are no good. Certainly there is a decent amount of play in the cap and it will rotate a bit from side to side. Is it worth changing the rotor at the same time?

Anyway, thanks for all the help from everyone, especially Mr Noisy with the advice and offers to come over to have a look at it.

What causes stalling when hot? Poor fuel supply from a dodgy fuel pump/sender unit. The End!!

I had a similar problem last week. Drove the usual 15min drive from newport into cardiff and was sat in traffic doing high rev stop start for an hour and 45! Was not impressed. The engines revs faltered then cut out but could be saved by giving it some balls again. problem was that the engine was getting pretty hot even though i do a fluid top up and check every month. I believe it happened because being such a big engine it needs the larger influx of air to keep it cool and not getting out of second for that long is never going to be good for it or keep it cool enough. As it got hotter it would cut out even more so the carpark was a bit of a nightmare. Though having sit to cool for the 3 hours as i was rockin ro status quo it ean perfect again and has since

Result

parajez said:

I had a similar problem last week. Drove the usual 15min drive from newport into cardiff and was sat in traffic doing high rev stop start for an hour and 45! Was not impressed. The engines revs faltered then cut out but could be saved by giving it some balls again. problem was that the engine was getting pretty hot even though i do a fluid top up and check every month. I believe it happened because being such a big engine it needs the larger influx of air to keep it cool and not getting out of second for that long is never going to be good for it or keep it cool enough. As it got hotter it would cut out even more so the carpark was a bit of a nightmare. Though having sit to cool for the 3 hours as i was rockin ro status quo it ean perfect again and has since

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Mine was similar to that. It was slowly getting worse and worse until in the end it wouldn't run for 10 minutes sat on the drive without cutting out.

Sounds like you might need a new fuel pump unit too. Got mine for £40+ from Rimmer Bros.