Fuel pump failed some time ago so replaced it. But since then it is sometimes difficult to start when warm and been standing for some time. First thing in morning starts fine, but when warm turns over longer and then fires but struggles as though no fuel (sometimes even stalling). A blip of throttle helps and drives fine once running. 2004 4.4 V8 - any suggestions appreciated.
Thanks! Current: 2004 Vogue 4.4 V8 - 2004 Discovery 2
Previous: 2000 P38 DHSE - 1995 P38 DT Man - 1990 3.9 SE Classic, 1980 3.5 Classic 2dr

Is this only happening when the engine is warm or does it also have starting issues when cold ?

If it is only when warm, it could be a sensor (crank / camshaft for example) starting to fail. Or the heat is affecting one or more injectors.

Also check for heat shields near the fuel lines missing that could cause vapour lock.

Also can you try the following, turn the ignition to position 2 but wait with the actual starting for a few seconds. If there is vapour in the lines then the waiting may reduce the vapour a bit by pumping petrol in.

It could also be a fuel line leak that only happens when the engine bay and fuel line is hot, so a very small crack in the steel fuel line that allows the fuel to get out but only when the line is hot and the crack opens up a bit. Check for petrol smell before starting the warm engine.

If it also happens when cold then it could be a non return valve leaking (letting fuel go back into the tank from the fuel line) or an injector leaking a bit and the fuel leaking into the combustion chamber making it over rich and emptying the fuel line partially. MY 2010 5.0 SC Galway green and sand interior!!
Have the Faultmate MSV2 Extreme to be tinkering with the settings etc. !!

Ebajema - thanks for your reply! It's never been a problem when cold!! I'll look into the other suggestions.  Current: 2004 Vogue 4.4 V8 - 2004 Discovery 2
Previous: 2000 P38 DHSE - 1995 P38 DT Man - 1990 3.9 SE Classic, 1980 3.5 Classic 2dr

At least that limits the potential problem areas. May I suggest to also look at BMW forums and see if this type of issue also happens with the 4.4 V8 in BMWs ??

By the way, I'm assuming the fuel pump was a new pump and not a reconditioned one ? In the latter case there could be an issue with the work done on it causing this problem. Did you have any sign of the problem before replacing the fuel pump ?? MY 2010 5.0 SC Galway green and sand interior!!
Have the Faultmate MSV2 Extreme to be tinkering with the settings etc. !!

The pump was a new one, but I can't actually remember if I was having this issue beforehand or not. I've just been out and tried it - it's been standing for about 2 hours which would normally cause the issue. There was no smell of fuel so I tried waiting like you suggested (about 30 seconds) and it started fine. I'll keep trying this to see if it works every time. Will keep you posted!
Thanks again! Current: 2004 Vogue 4.4 V8 - 2004 Discovery 2
Previous: 2000 P38 DHSE - 1995 P38 DT Man - 1990 3.9 SE Classic, 1980 3.5 Classic 2dr

Glad the longer wait seems to do the trick, not that it helps you with finding the cause though. Good to hear there seems to be no leakage though. MY 2010 5.0 SC Galway green and sand interior!!
Have the Faultmate MSV2 Extreme to be tinkering with the settings etc. !!

I have had this same warm starting issue in the past, turned out that it was the fuel filter (located under the removal panel near the fuel tank) has a couple of clip on fuel pipes. I replaced it and my issues instantly went away and have never had any starting issues since

Matt Current
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Mattstevenson2005 - aha! Something else to check, thanks  Current: 2004 Vogue 4.4 V8 - 2004 Discovery 2
Previous: 2000 P38 DHSE - 1995 P38 DT Man - 1990 3.9 SE Classic, 1980 3.5 Classic 2dr

Checked the filter and remembered I'd changed it at same time as fitting new pump. One thing I did notice: the Schrader valve on the fuel rail was a little loose so tightened it up! Will see if this makes a difference. Current: 2004 Vogue 4.4 V8 - 2004 Discovery 2
Previous: 2000 P38 DHSE - 1995 P38 DT Man - 1990 3.9 SE Classic, 1980 3.5 Classic 2dr

Had this issue as well after putting in a new fuel pump.Wasnt the pump or the filter or loss of pressure at the fuel rail.It was the camshaft position sensor on bank 2 which was acting up.Diagnosed by my mechanic.

The loose Schrader valve could make a difference although I'd still expect it to be acting up when cold as well. Maybe it is when cold that it gets just a little more time to build up pressure  MY 2010 5.0 SC Galway green and sand interior!!
Have the Faultmate MSV2 Extreme to be tinkering with the settings etc. !!

It hasn't been as bad since tightening the valve, but does occasionally sound as though it's not going to run - ie it doesn't rev up at all. Current: 2004 Vogue 4.4 V8 - 2004 Discovery 2
Previous: 2000 P38 DHSE - 1995 P38 DT Man - 1990 3.9 SE Classic, 1980 3.5 Classic 2dr

Just keep looking for the suggested markers. A small crack seems the most logical reason. Have you looked around the Schrader valve if there are any signs of petrol leakage ? Maybe it came loose because there is a little crack in the fitting that allows it to loosen ?? MY 2010 5.0 SC Galway green and sand interior!!
Have the Faultmate MSV2 Extreme to be tinkering with the settings etc. !!

Today the weather is really warm (25 dregs in May is hot). First thing this morning started fine. Drove 3 miles and parked up for 5 hours, left in full sun, started fine. Drove 3 miles home and left for 10 mins - really difficult to start! So worse the hotter the ambient temp.
One thought: when I bought it the plastic engine cover was missing and still is. Could the fuel rail be getting so hot that the fuel is evaporating? Current: 2004 Vogue 4.4 V8 - 2004 Discovery 2
Previous: 2000 P38 DHSE - 1995 P38 DT Man - 1990 3.9 SE Classic, 1980 3.5 Classic 2dr

Could be worn injectors, you switch off and they leak and dump fuel into the engine, won't start well until it has all evaporated as it floods the engine... before fly by wire you could crank it with a WOT to clear it but I don't know if that would work...!!!

Maybe worth a try though, floor it and crank and see if it starts easier...

Don't think the engine cover will do much, they are for aesthetics on a petrol and noise on a diesel... Pete
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