Engine Stalls when hot - 1990 2.1DJ 5 Speed

[shalfy1]

On a recent trip to Devon the engine completely stalled whilst driving along. No rough running or any indication before it happened.  Breakdown assistance 2 hours later couldn't sort it so got recovered back home.
I've had the van for 19 years so I'm familiar with various quirks/fault conditions of the vehicle.
The morning after it was recovered home it started straight away (of course, from cold) so I spent 5 days with my head in the engine bay checking through fault procedures in Bentleys and working my way through the wiring diagram.  All seemed OK and I drove it locally and it stalled after a couple of miles, just before a bus stop which I freewheeled into.  This time had it recovered to a local garage where a retired "old school" mechanic, Bob, checked it out.  Of course, in the morning it would start fine. He cleaned up the earth connections in the engine bay and checked sparks, injectors squirting, fuel pump pumping and couldn't get it to fail so we went for a test drive for about 45 minutes.  All seemed well, so I drove home (oh no I didn't).  I got half a mile down the road and it died again (luckily on a fairly quiet, wide road).  I called Bob and he came over but couldn't find out why it had died.  I left it by the side of the road and in the morning it started straight away and I immediately drove it to my house (about 3 miles away), left it idling on the drive and it died after about 10 minutes.  So, a familiar theme is appearing - it starts and drives lovely when cold then dies when hot.
It has now been on my drive for a week and I can get it to die fairly regularly by letting it get hot, hot, hot (2nd stage fan has to kick in at least a couple of times), blip the throttle and it will die.  Wait 30 seconds(ish), prime the fuel pump a couple of times and it will  start again at idle, then usually die as soon as I give it throttle. Do it again - wait 30 seconds(ish), prime the fuel pump a couple of times and it will  start again at idle, then usually die as soon as I give it throttle. Repeat ad nauseam!

I've checked the following:-

• Fuel delivery
  
• Throttle position switch
  
• AFM (cleaned track, clean linear voltage out as flap moved)
  
• Coolant Temp I sender within graph (at ambient and high water temperature)
  
• Air intake Temp II Sender within graph (at ambient air temp)
  
• Replaced coil, dizzy cap/rotor/ht lead
  
• Checked connectors for tightness/corrosion
  
• ECU connector - to earths/ISCU/relays/AFM/temp senders
  
• Replaced TCI module
  

So, there you have it.  I'm stumped and Bob is stumped.  I've been avoiding speculating on causes, and without a known good ECU and ISCU to try at the crucial temperature (hot,hot,hot), I'm stumped as to what to try next and believe me, waking up a 3am in the morning worrying about it doesn't seem to help.  Any useful suggestions most gratefully welcomed.

[davidoft1]

Check for spark it may be the hall sender starting to fail and being effected by heat

[mrhutch]

Check for spark it may be the hall sender starting to fail and being effected by heat

THIS 

Check everything again  - especially spark when it is HOT

[shalfy1]

Just added an amendment to original description.
Wait 30 seconds(ish), prime the fuel pump a couple of times and it will  start again at idle, then usually die as soon as I give it throttle. 
Do it again, and again.  Surely wouldn't even start again if it was spark?

[mrhutch]

IMHO as davidoft1 said it still could be hall sender - or leads - or coil..  increased load at higher rpms when hot causing failure?

Checked impedance of leads?

[jrt]

I would have thought coil but if it’s a new one that probably rules it out.
Swap the manual fuel pump for an electric one down by the tank maybe??
David.

[shalfy1]

I would have thought coil but if it’s a new one that probably rules it out.
Swap the manual fuel pump for an electric one down by the tank maybe??
David.

It is an electric fuel pump down by the tank - it's fuel injection

[shalfy1]

IMHO as davidoft1 said it still could be hall sender - or leads - or coil..  increased load at higher rpms when hot causing failure?

Checked impedance of leads?

I'll try that tomorrow - too frazzled today.

[shalfy1]

Update from today's investigations.
Van sat idling on drive for about an hour to get really hot before it dies.
Started up again to idle then dies on throttle (tps checks ok).
Started up again and checked spark whilst it dies on throttle - spark OK (so I think hall sender/TCI/coil all OK).
Fuel delivery through FP regulator checked OK.
I suspect ECU fault or ISCU fault, but without known good ECU or ISCU to compare I'm at a loss as to what to do next.
Any suggestions, or anyone out there has loan ECU or ISCU for late model 2.1DJ?