L322 starting issues M62

hi guys still got my starting issues, been going on around 6 months now and still can't get to the bottom of it. ok so if i start the car from cold starts first time everytime no issues, it drives with no loss of power or any problems, now when i switch the engine off, this could be after 2mins or 2 hours if i leave the car for longer than 5 mins when i try to start the car back up, it cranks over for an extended period of time then fires but it's almost like the fuel lines had ben drained and it slowly comes to life a quick blip of the throttle brings it upto idle speed. once started however the car runs fine with no loss of power on both petrol & LPG, and i've done several long journeys on petrol to confirm.

so far i have had the car serviced, new plugs, fuel filter etc, etc.
replaced the crank angle sensor and reset all the long term fuel trims
checked for air leaks with nothing found
i did have strong fuel smell from the front corner, the car was checked and there were no leaks anywhere, anyway i unplugged the fuel tank vent valve cleaned the contacts and that's been fine since.
there are no fault codes in the EMS ecu

the last few days when starting the car after it's been stood i've been turning the ignition on, letting it sit for about 30-secs to 1 min then firing the car up, so far it's started normally everytime. i don't know if there is any kind of one way valve in the fuel system, but my guess it would be in the fuel filter, and it was the same with previous & current filter.
would the fuel pump or relay be a possible culprit? although i would expect performance problems which i'm not having issues with.
i'm really at my wits end with this now and just want to get it fixed.

Fuel pump is my first guess - second guess is fuel injector(s) - but not likely.

Start with your fuel pump relay and work back to the pump. The fact you have to let it sit with the key turned to II tells me the pump is building up pressure.

That's my thoughts, but it's not struggling to supply fuel when it's running, I can floor it and it goes, and no issues when cold

I have seen postings similar to yours and most resolved the issue by changing the fuel filter (which you say you did) or the fuel pump. I thought I had a fuel pump issue so I looked at many posts.

One thing is that some owners had your type of issues after they changed the fuel pump because they used the wrong type of hose clamp. My theory is fuel would leak out enough to cause issues, but under power enough gets through to work. I did see one post about a relay that was intermittent - so maybe look at this first as it is easiest. I believe it is in the back and there is another relay you can swap right by it for testing. If it solves the problem buy another relay and you are good to go.

I suppose you can put a fuel pressure gauge on and measure fuel pressure at various stages to see if you can isolate it to the fuel pump.

yes i too have seen the posts but they all have cold start issues too, mine starts on the button on a cold start which is strange to say the least, i think first port of call is swapping that relay, and a pressure test on the fuel line. i think i may check pressures with the current relay and the 'swapped' one in place for comparison.

If it was a carb I would suggest fuel evaporation, I don't know it injection systems suffer from this problem though. Can you fit a temporary heat shield between the inlet manifold and exhaust? Sorry if this is completely irrelevant.

Col

hi col, no evaporation on the l322, it's a direct rail injection system, which has the pressure regulator fitted into the fuel filter at the back of the car only real place they suffer is injector seals if they leak, but the cars been checked over and the garage couldn't find any fuel leaks, it's really strange as it starts immediately when cold but even after a 2min run it turns over for longer than expected then splutters into life. i've got a day of maintenance lined up today so checking the fuel pump & relay in on the list along with fuel pressure i'm also going to do a hard reset to see if things improve incase it's a faulty sensor reading somewhere.

You could fit a cheap in-line NRV @RRkev

I'd be checking shraeder valve on the rail after switch off, allowing however many minutes it usually doesn't fire for you.
Cover area well with towelling as fuel should spurt out around 10 inches.
Not very high tech, maybe a dongle would give live data rail pressure? (3-3.5Bar)

I read some tip about the inlet manifold gaskets shrinking and the use of washers that fit over the retaining bolt limit tubes (X10) helping to squish them a bit further rather than dismantling to fit new ones, maybe spray carb cleaner around manifold mating faces, if the engine revs rise then you have the gasket issue which may affect the fuelling metering.

Maybe just a bad pump relay?

So as I was replacing my rear brakes today I did the hard reset, during that time connected everything up, started it up for 10 mins, went for a shower, came back still spluttering into life. Anyway took it for a long run on petrol. Decided to swap the heated seat and fuel pump relays over, to test and low and behold it's had 2 short runs now, where it's been stood about 5 mins before restarting and so far so good. Hopefully that's fixed it will test it over the next few days so fingers crossed. Now I just need to replace the rear brake hoses, and looks like f to r brake pipes too, I don't fancy the chances of undoing the unions.

Sounds promising re. relay.

Re. brake unions, just cut pipes off and get either mole grips on them or a 6 sided socket, next size down if needs be.
You'll be replacing unions anyways so do what you have to.
Just remember to add 20mm to the new pipe if you do cut them.

You do know the string measuring trick for pipework?

yes, i don't have any brake pipe making kit, but luckily i have a neighbour who works at a local garage so they do me a 'cash' deal, so i'll be taking it to them to be sorted. my other problem i found was one of my handbrake shoes didn't have a retaining pin, so the shoe was angled in the disc, must have been like it since i bought the car as there was no sign of a retaining pin, but luckily was replacing everything discs included. however it seems my backing plate isn't great so i need to keep an eye on that too

well it seems even though the car is running better i still have the issue with the hot start, it's doing it if i start on LPG as well so ruled out fuel pump, not really mentioned in land rover circles but on the BMW boards it's full of the same issue and all pointing to the temp sensor going faulty. as it's under £20 to replace that is my next step.

ok just to finally put this to bed as there seems to be loads of other people with the same issue and no fix, i have now replaced the coolant temp sensor. and it seems to have cured the problem for me, so for circa £15 it's worth a try. part number for the temp sensor is 1703993, it says oil temp sensor, but it is the correct part. the sensor goes faulty and registers a lower engine temp with the ecu after the car has been stood, but the car is a higher temp so it pumps more fuel in effectively flooding the engine and causing it to splutter into life.