Decided to fit with pronounced ridge facing into engine side . I didn't notice any damage to the old seal or O rings but replaced them anyway and it seems to be fine with no leaks Trouble is its made no difference whatsoever so looks like that was not the cause of the problem. if nothing else at least I can tick this off hit list/
Perhaps the problem is the new low pressure pump only achieving a reading of 344.To be honest I'm running out of things to check. I've been trying to find online if there is an official specified minimum pressure for this lp pump. Does anyone have a TD4 that starts fine with a LP reading below 350 at idle ?

Ordered and fitted a new delphi pump this morning but although the low pressure is now a healthy 77kpa it has not cured the problem.
Im genuinely gutted as really thought this would have been the solution. Need to get it plugged in to a proper diagnostics machine and seek help as run out of ideas.
Thanks everyone for your efforts much appreciated

Hi Rednal
Sorry for your lack of success so far.
Can you explain something though regarding your description of the fault.
You mention changing starter motor etc - also solenoid contacts ? - when you say '4 or 5 times to start' and 'starting problems' are you referring to the engine turning over slowly ? - or turning over normally (normal starting / cranking speed) ? I can see no logic in looking towards the starter unless you presuming it was turning sluggishly ?
So, can you please explain the issue in a bit more detail. - especially relating to your thoughts on starter motor possible faults etc ?.

Some issues CAN be caused by voltage drops on cranking due to earth issues to sensitive components (causing voltage drops) - however, measuring with a normal multi-meter can give misleading results due to the input impedance. You usually need a small load - a test lamp for example - a few hundred mA - to see a genuine drop if it is there. -
A quick test for poor connections is to put the headlights on and crank the vehicle and see if cranking speed alters or lights dim significantly.

Another quick and useful test to try is to use jump leads from your relations vehicle. Connect the negative from his battery to a good chassis earth on your vehicle and the positive terminal of each battery to each other. Then try and see if any difference - this will check for poor earthing.
If not successful - move the earth clamp from the jump lead on your vehicle to a ground on the engine itself and try again. Don't connect battery negative from the other vehicle to battery negative on yours - go directly from battery negative post on his to chassis ground on yours- then the engine block / main metal lump / itself on yours.

Let me know the results.
Joe

Hi thanks for quick reply. Yes one of the first jobs I done was to change the solenoids on original starter as this was a common tip on forums. I noticed on removal however that part of the starters mounting point was broken. I decided to replace full unit to ensure a good earth. It has always cranked powerfully enough and still does.Replacing the battery was probably not necessary but done so just to rule it out. It starts first turn of key in morning providing 9 hours overnight.
I turn key and let it crank for 5 or so seconds each time and yes its powerful cranking. What may be worth mentioning is that after say 5th or 6th try it may fire up very briefly for a second or two but not quite strong enough and cuts back out.
Its been Frustrating the life out of me (and neighbours ) for past 6 weeks.

you mention that it doesn't seem to start though after 9 hours during the daylight ? -
Is there a considerable temperature difference night and day at the moment (in your location) ?
Joe

No the temperature drop wouldnt be severe I reckon only about 10 degrees or so colder overnight . It seems to make difference though as even left for 10 hours during day is not enough.

Would you say the sunshine on the vehicle is making it considerably warmer (inside - under bonnet etc)? - or indeed, for example - if it is cold and raining - is it still the same - ok in morning - not ok in day ??? baffling...

Weather has been reasonable for past month so not had a long cold day for a while. Hopefully I get it fixed before winter and don't get to test that scenario

REDNAL3 said:

Weather has been reasonable for past month so not had a long cold day for a while. Hopefully I get it fixed before winter and don't get to test that scenario

Click to expand...

How long has the fault been occurring ?

It was bought with this known issue about 7 weeks ago. It drives absolutely perfect once started really like it and is purely a starting issue. More chance of me breaking down than the car

IF there is a DEFINITE issue between starting after 9 hours overnight, and NOT starting properly after 9 hours during the day - then that means something. - what - we will have to work out - but it is an important clue.
Ok, so now - to move forward - do a test - do NOT start it in the morning of the test !!- start it in the evening (ie - about 9 hours before you would normally start it in the morning - if that makes sense. - does it start perfectly ok ?? - as you say it would do in the morning. ??
Now - leave it over night - now does it have the starting issue the next morning - 9 hours later ?????

IF it does start ok in the evening after leaving it overnight and all day - then has problems in the morning - then then the issue is TIME related between starting - (something is happening over a period of time that is not at all dependent on temperature) - stick with me on this as we need to get a baseline -
If it still does not start in the evening - but starts in the following morning ok (in the above experiment ) then it would be fair to say the issue is probably temperature related (as that is really the only difference between night and day - ie - the sun on the vehicle and daily temps)

At the moment - believing that it actually starts ok in the morning but not in the day after the same length of time seems totally crazy (unless temp related) - the above tests will at least offer some more insight.

I can see reasons for a temperature OVER time related issue but not a time only issue - so we need to prove or otherwise the above. It may sound crazy - but these should really have been the first steps.

-------------------------------------------------------------
If we are looking at thermal, (after the above) get yourself some servisol or similar switch / contact cleaner -(NOT brake cleaner!!!) and remove the ecu plugs (after disconnecting the battery!) - give them all a good spray and also check for any signs of issues - corrosion, green gunk - dirt - burning signs etc)
Salme with other connectors you can reach - but mainly ecu/

We also also 'Cool' important things to test if it appears temperature related by using a freezing spray from a plumbers merchant (used to freeze water in pipes) - it is in a simple aerosol (We use it all the time (or the servisol equivalent) in electronics work if a thermal component issue is suspected).. it could be - for example - sprayed onto an ecu case when warm and not starting to see if it makes a difference as it will rapidly cool it - (even form ICE on it if needed ) - also other engine sensors.
Again if thermal - I would suspect electrical issues - fusebox area - inside earth points etc etc.
But to get around this apparently seemingly (at first) totally illogical morning ok - later day not idea - first you have to go and prove it one way or the other. Dont start doing things, changing things or spending more money until a few simple tests are done - like the starting - when fault finding - it always needs a logical approach - the fact it starts at one time gives us a clue that - at one time - all is ok - and it is repeatable - next step - is it repeatable later in the day after NOT starting it in the morning.

Hope that makes sense ....................
Joe

Hi I have more or less pinned the overnight pattern down. It definitely needs minimum of 9 or more hours overnight ideally 11. I experimented by driving the car beyond certain times 9pm , 10pm etc and tried starting at 7am. I found that If it was last used beyond 8pm it would struggle next morning.. Ill try to have look at ecu contacts tomorrow and get that spray. Next door is AA guy and he cant understand it either. Really need someone local with a diagnostics or else get a job doing nightshifts

REDNAL3 said:

Hi I have more or less pinned the overnight pattern down. It definitely needs minimum of 9 or more hours overnight ideally 11. I experimented by driving the car beyond certain times 9pm , 10pm etc and tried starting at 7am. I found that If it was last used beyond 8pm it would struggle next morning.. Ill try to have look at ecu contacts tomorrow and get that spray. Next door is AA guy and he cant understand it either. Really need someone local with a diagnostics or else get a job doing nightshifts

Click to expand...

To clarify - have you left the car from the night before until - say - 8PM at night ? - does it then start fine at 8pm at night ?

No I haven't done that as far as I can recall as the car is used every day of the week.I'll try that if I can get an opportunity. Tomorrow Ill check around the ecu and see what I can use that freezing spray on,

Surely you don' t need to use the car 7 days a week ? maybe you do ??? -
Can you not get a lift one day ? - if the car wont start at 8pm in the evening after being left for 24 hours including a day out in the sun - then it is almost certainly thermal related. - but do the test !. you need to identify where you are starting from instead of just jumping in and changing something..

Also don't go too mad to start with - freezing sprays etc are for specialist fault finding only. ! - not for now !.

Start off cleaning all the ECU connections with GENUINE contact cleaner (Basically remove battery - remove the ecu plugs - spray liberally inside the plugs and the ecu sockets and replace.)

BUT ! do the simple test of the wait 24 hours until the evening to see if it is simple thermal.

Yes will try and leave car sitting 24 hours at some point next week.Thanks again for your advice on this ! !

Ok tried both exercises now. On Thursday I removed and sprayed electrical cleaner on every connector I could find plus all the ecu sockets relays etc.Tried to start afterwards but same result (5 crank attempts before it would start) . I then gave second experiment a go. I last used car Friday 9pm and have just tried it at 8pm this evening. (again not starting). I know it would have started first time had I tried at 7am this morning as it always does. It certainly points to being a thermal issue but not sure which part would be so sensitive. I did find one thing however whilst spraying connectors on thursday. The pressure sensor cable was partially flattened as it had been trapped against engine by inlet manifold. I cut the loom protection but couldnt see any obvious damage to wires.I straightened them out and taped them up but made no difference.(started 7am next morning and struggled to start later in afternoon). I am going to replace that harness anyway but not convinced thats the issue. Whats your thoughts ???
.

I am rather baffled as non of the tests you have done are really conclusive - 1 overnight session doesn't prove it is thermal - it doesn't rule it out either.
If it WAS a thermal issue, I would expect it to also show at other times and progressively get worse the hotter things got.
I would also say that any major sensor - cam crank etc etc would not just be problematic during starting which I would say would rule those out.

I would be tempted to look again at you fuel system. Have you actually hooked up the 930 tester when starting to see what readings you have ? - both when it starts well and when it does not. - It sounds like you are losing fuel pressure somewhere.... but once started it is ok.

What happens if you start it (when it starts ok) - run it for 10 mins / 30 mins etc, then stop and restart ??
I think if you cannot see real time diagnostics during the starting period then you need to find someone who has the appropriate test gear.

If I start it in morning drive for say 20 minutes and stop. I can restart it no problem. If i leave it for 20 mins or more though it will struggle again.What readings would you expect to see at idle ? I did post my readings previously and seemed to be in line with others.I think it was Low pressure end 74kpa and high pressure 28500 kpa. If it is pressure related why would it consistently start no problem first time in mornings even if it wasnt starting previous evening? Its driving me nuts trying to decipher what could be going on.

The TD4 guys can answer the pressure questions far better than I could as I have an L series.
The interesting figures would be the actual pressures logged real time from key on to running during the starting (or difficult starting) - you seem to have replaced most other components. I am not convinced re the morning / afternoon issues - thermal cannot be rules out - but one overnight test would not make it definite.
What if you drive it for an hour or more and stop - does it start again - in - say within 20 mins ? - if so - it probably is not thermal. It almost sounds as if you are losing pressure in the common rail. - I would be seriously looking at the pressure control valve. Real time diagnostics will rule in or out this issue.
Probably for the money you have spent you could have bought a Lynx or Hawkeye.

Figures from RAVE quote a minimum starting pressure of 200 bar (20,000 Kpa) and for 300 bar (30,000 kpa) at idle.
Only when you have absolutely ruled that out by proper diagnostic testing would I recommend you move on.