Idle stall and no restart problem

[dogbucket]

Hi,

Another one of those annoying idle cutout problems.

Car has been doing this for the last couple of years and only really occurs when left idling for more ten minutes or so. General driving around is ok, but it is denting my confidence in wanting to use it more.

Engine dies pretty quick and will often not restart for several minutes (turns over fine)

Things I have looked into so far :

1 There is still a spark when it wont restart (did replace coil and amp)
2 Fuel pump still primes and runs normally when it wont restart
3 Rovergauge does not show anything untoward before or after the stall, no error codes logged.
4 Swapped the relays but noticed one in black socket gets quite warm
5 Today after a lengthy investigation had the MIL light come on a few times whilst it was not restarting
6 Could be related to under bonnet temps, fuel temp got up to 42deg

Any help appreciated. I suspect it can only be the injection system or associated wiring breaking down.

[dogbucket]

Relays are both the original red stripe ones. ECU is the one that always gets warm, but that could be normal.

Rovergauge still says no errors logged.

Looking through the rovergauge logs it confirms my feeling that the engine always stalls just after the cooling fans kick in as the ECU volts drops from 13.63V to 13.2V. Even when it does not stall I have always noticed the engine has to trim the idle slightly when the fans kick in. Still confused why it does not restart straight away, perhaps it floods.

I think my next thing is therefore fuel pump voltage and maybe fuel filter as that has not been changed for a while

Edited by dogbucket on Monday 4th April 19:23

[dogbucket]

I was also considering the Mod-Wise cooling kit, but had no response to emails. Anybody know if he is still operating?

[dogbucket]

UPDATE

Still investigating this particularly as the recent MOT had to be abandoned as I wasted so much time trying to get it restarted after it stalled!

I am pretty sure it is fundamentally a lack of fuel problem as the plug are dry and there is a spark, but triggered by heat under the bonnet.

Looking at Rovergauge the normal startup sequence in regards to the fuel pump seems to be :

Ignition on
Fuel relay on for 2s then off (and priming sound)
Start cranking
Fuel relay back on and engine fires

When it stalled and failed to restart today :

Ignition on
Fuel relay on for 2s then off (and priming sound)
Start cranking
Fuel relay remains off (according to Rovergauge)

Using Rovergauge to run pump continuously it did restart, but I then turned run continuously off and of course it stalled and threw the MIL light. Had to wait a while for the MIL to clear before it restarted normally.

So my understanding is in the cranking sequence the ECU waits for a return signal from the ignition amp before running the pump continuously. Is this correct and if the ignition amp is still working in regards to triggering the coil that seems odd. Is there anything else that the ECU uses to decide when to turn on the fuel pump?

Edited by dogbucket on Monday 27th June 19:47

[dogbucket]

I started looking for the resistor that allegedly sits between the coil/amp and ECU pin39. Found 2 Lucas black things on spade terminals in line with the wiring around the coil. One reads the expected 6.8k the other is open circuit?