Trouble starting, then cuts out when idling - SORTED!

Hi Folks,
Well I've had a similar thread in the past but here goes!
So.. the disco 2 is difficult to start. If its previously cut out, you can hear the fuel pump noise and a surge of fuel (from the engine bay) when you first tun the key. Cranking it over for @20 seconds at a time, after the third or fourth try the engine will eventually fire up amongst a (sometimes) small cloud of smoke and run. Drive it for an hour on the motorway or 10 minutes down a country lane, it makes no difference.. when you stop, maybe traffic lights etc it is very likely to cut out. Then its a real pain to start again. you can tell its going to happen, the engine starts running a little rough at idle, a knocking noise starts and then it cuts out. If I start the car in the drive and leave it idling, in 5 minutes it will run rough and cut-out.
So, at first I thought this was fuel starvation, air getting in somehow? fuel running back to the tank? pressure dropping etc.. I've changed:
New fuel pump
New fuel pressure regulator
New fuel filter
New water separator
New fuel filter housing
New valve filter 'thingy' in the fuel filter housing
(mine doesn't have a non-return valve on the other fuel connector)
I've changed the injector washers and o-ring's (although the originals looked OK)
I've bypassed the fuel cooler unit
I've replaced the cluster of 4 fuel pipes at the rear
I've taken the tank off and cleaned and checked the filler and breather pipes
I've had made a high pressure fuel pipe and bypassed the two long-run fuel pipes from the back to the front of the car.
So... that's the ENTIRE fuel setup on a disco2 and I STILL HAVE THE PROBLEM !!
I'm completely at wits end with this.. is there anything electrical that can cause this problem?
Oh.. I've also changed the crankcase sensor and the injector harness..
any ideas anyone?

You could look at crank speed sensor

Not sure which one that is?.. the one I replaced was on the bell-housing. Surely that wouldn't cause the fuel to keep wanting to pressurise itself? i have a fuel pressurising noise every time I go to start the car

That noise you describe as pressurizing the fuel is normal, its the pump running,
didnt see the original post where you said you changed the crank sensor,
have you had it plugged into diagnostics,

Yes, I have a Nanocom.. No reports of anything wrong. Even if I look at the fuelling inputs whilst the car is running, it's fine and simply drops out when the car engine does, no sign of any issues, nothing in the logs

People have had similar problems when the air release in the fuel tank cap fails causing a vacuum, try running it with the cap unscrewed to allow air to enter the tank, if any better get a new cap

Unfortunately I have tried this too.. I've tried leaving the cap off on the chance that the tank wasn't 'breathing' but no luck with that either.. This really has me stumped!

is your oil level moving? im susecting a cracked cylinder head

It doesn't seem to be, the oil level is constant. The car also doesn't seem to be losing any fluids anywhere, with no smoke out the back at all.. Well only the occasional small cloud after I've been turning the engine over several times to get it started again

Just to add, the water level is constant too..

Your symptoms are identical to mine, when my injector seals had gone! BUT you said you changed the seals! Its the copper washer failing that usually causes the bad start then stalling. Were you very certain that all the mating surfaces were spotless when you installed the injectors?
When my head cracked (later) at No1 injector pocket, the car was running fine but it could still be a cracked head.
Even if your oil level is not rising its worth checking for leaks, remove the rocker cover and turn on the ignition, DO NOT start the engine.
Start the fuel purge.
Take your time and use a good torch, look around each injector for any bubbles or weeps, you shouldn't see any bubbles!
As suggested before its still worth changing your CPS and checking the wiring, it could be an intermittent fault with that, and electrical noise from the starter can affect signal from the CPS.
Mark

If it's manual remove the starter relay and try to bump start it, if it starts right away replace the starter

Thanks folks.. More for me to work with.
It's an auto box., can you explain a little more on why the starter relay?
I'll look at the crank position sensor wiring

Thed starter relay is supposed to be removed on bump start for this particular case(only on manuals) to be able to turn ignition to crank without activating the starter while it's bump started... there are cases(quite common) that due to a internal problem of the starter(can't tell exactly what) it disturbes the crank signal and makes it very difficult to start, unfortunately on auto the only way to rule this out is to replace the starter while on manuals if the bump start works well it's confirmed, usually this brings a "noisy crank signal" fault code but i've seen cases without that

One further thing to add.. The non-starting is a constant, what I mean by this is that it always takes 3 times to crank the engine over.. Cranking for 10 seconds or so. On the third time, it starts to splutter and then then it will start to fire. If I turn off the engine at that point, it will fire straight away and will continue to do so unless it has stalled itself again
This is why my thoughts were related to fuel pressure. I'm thinking that if it were the crankcase sensor or the wiring it would be more sporadic in its starting? Thoughts anyone?

Yes, i've got carried away with the starting issue and forgot about the stalling thing so the starter is out of the ecuation... the crank sensor is a good point to start with in this case... it can have a very strange behaviour though if it starts instantly after a purging sequence a combustion gas leak into the fuel rail is more suspect

Before I go tearing the top off the engine again and looking at the injectors I.e.what Markomate2 indicates.. Could the injector harness cause this at all? Again, I would suspect it to be more sporadic than predictive?

Hi
Do whatever you can first to narrow it down, before having a go at the head!
Sounds like your starter is ok, but you cant do sierraferys test as its an auto.
Check the CPS and its wiring, check the plug connections.
Its not unknown for a brand new part to be faulty, so check your injector harness and replace/borrow another if you can.
Mark

Ok, latest update... It's not the CPS. Replaced it and it made no difference. Whilst the car engine was running (I had the car on some ramps), I 'played' with the CPS lead and connector and couldn't get the engine to die. I also checked-out the loom that the CPS connector was integrated into. No apparent faults there...
Can someone do me a favour?... Pop the bonnet on your disco 2, turn the ignition on but don't start the car.. Can you hear fuel being 'driven/ surging' to the fuel pressure regulator and the fuel cooler? On mine it sound like the fuel is being driven/ flowing through the system. I may be wrong, but I thought the system pressurised itself and then stopped surging.

Oh well it, its eliminated one of the easier fixes!
Yes I can hear TD5 fuel flowing through the head very nicely!
Funny thing happened this morning though, I went to start it, kicked over as usual then immediately stalled, tried starting again, cranked over like crazy but wouldnt start!!!!
Never done that before!
On a hunch I stayed in the car, locked it with the remote, and then unlocked it, lo and behold, she starts, been ok since.
Could just have been a coincidence but I really think it was something to do with the alarm!
Worth looking at on yours?
Mark