LandRoverAnorak wrote:

Check that the battery earth connection is tight.

Thanks LandRoverAnorak - tried that, including a change of battery

blackwolf wrote:

Volume Control Valve. Probably the first thing I would have changed.

GreenArmour wrote:

blackwolf wrote:

Volume Control Valve. Probably the first thing I would have changed.

Thanks Blackwolf - I have seen your name pop up in loads of posts so appreciate your response on this one. Is the 'volume control valve' the same thing as the 'fuel injector pump vapour sensor (part number LR009837)'?

Item 4 on this diagram...

https://www.landroverworkshop.com/diagrams...mp_45001#4

Minch90 wrote:

Really long shot, mine did this intermittently for about a week before the water pump died

Thanks Minch - been doing this ever since I bought it, 8 months ago. I would think the water pump would have given up completely in that time

shropshiredefender wrote:

Your symptoms are the same as I had some time ago. The cause was the cylinder head temperature sensor was cutting power as the temperature rose above normal, there was no rise shown on the temperature gauge. I drove 150 ish motorway miles with no problem, but in traffic before and after the motorway I had power loss. No fault codes. I was convinced that it was bad diesel. Turned out to be a small leak in the radiator.
http://www.defender2.net/forum/topic54988.html

The point is that the Cylinder Head Temperature Sensor reduces fuel rail pressure when it goes outside its normal range.
It seems to be much more sensitive than the temperature gauge.
When it operates there are no fault codes.
It quickly returns to normal as the temperature drops.
At motorway speeds air flow through the radiator is high enough to counteract low coolant level/low coolant flow.
To reduce temperature in the cooling system it cuts the aircon.

I was so convinced that the problem was fuel related that I did not check the coolant level.
After returning home I drove to my independent and suggested that it was a fuel related problem.
He took it for a test drive and a mile or so away from his garage it cut out and would not start.
He checked levels as a matter of course, added water and all was OK.

Anyway if the water level is OK it might be worth while to change the CHT sensor and check the cooling system.

Be Lucky

I spent ages trying to prove it was all temp related by monitoring the digital readings on the ultragauge. My conclusion was that it wasn’t as once up to running temp you would expect that it would happen again (after a 2 min off reset) a lot quicker than from cold... I have been wrong about the turbo, actuator, maf, map, boost pipes, wiring loom, fuel filter so not ruling out being wrong about temp either

blackwolf wrote:

GreenArmour wrote:

blackwolf wrote:

Volume Control Valve. Probably the first thing I would have changed.

Thanks Blackwolf - I have seen your name pop up in loads of posts so appreciate your response on this one. Is the 'volume control valve' the same thing as the 'fuel injector pump vapour sensor (part number LR009837)'?

Item 4 on this diagram...

https://www.landroverworkshop.com/diagrams...mp_45001#4

Yes, that's the thing.

It may not of course be your problem, but it is usually the first thing to suspect in the case of poor running in the absence of DTCs, since the parts of the fuel system it affects are poorly monitored. If it is sticking and is not sufficiently responsive it is entirely possible that the fuel rail pressure is not reacting quickly enough to increased demand, such as the off-throttle/on-throttle sequence.

The first time I had one fail I was convinced I have a fuel contamination issue leading to the filter blocking, since I would get fuel starvation symptoms (fine on tickover but massive misfires/stalling etc when accelerating). If you stopped for a couple of minutes (usually I would drain some fuel out of the filter), then start up and it would be fine for a while, then repeat the cycle. Eventually the "fine" intervals got shorter and shorter. There were no fault codes at all.

Eventually (and after trying many fuel related things) I spoke to a main dealer's senior tech (a very helpful person who has provided me with advice on many occasions) who said that he would change the VCV and if that didn't sort it the EGR (which is disabled anyway on my Defender). New VCV and all was right as rain.

His comment was that the VCV is absurdly fragile and is very prone to failing, especially if any water or dirt gets in the fuel. He also said that his dealership changed them very regularly and found that it was the single most common fault with the Ford-engined Defenders. The Ford dealer I bought my replacement from sold so many that the parts man knew the part number off the top of his head and kept a stock under the counter.

In the end I came to the conclusion that my problem was indeed fuel contamination, since I had an unhealthy dose of the dreaded diesel bug, but it wasn't blocking the filter as I had thought but had instead knackered the VCV. Prior to changing the VCV I had dropped the tank and cleaned it, cleaned all the fuel lines, and had all my fuel professionally "polished" (it was shocking how much crud and detritus came out of supposedly clean fuel).

VCV on order! Please, please, please let it be that