Help - 6 mechanics later no one has figured this out

[bees knees]

2014 transit...
156000 miles...
If I drive for lets say half hour/hour - engine warm....and I stop the van and leave her for an hour - fine - starts no problem
If I drive the same amount of time - and nip into a shop or a toilet - 5 /10 mins - it won't start.....
Today was the worst - it wouldn't start - and I got "brake system service" when I tried - and the brake pedal was solid.
Left it for another while - and it started fine. And has been starting since.
Its only when turned off for a short time that the problem happens.

Battery and alternator tested fine.

Any help badly needed and appreciated.

[knobby1]

2014 transit...
156000 miles...
If I drive for lets say half hour/hour - engine warm....and I stop the van and leave her for an hour - fine - starts no problem
If I drive the same amount of time - and nip into a shop or a toilet - 5 /10 mins - it won't start.....
Today was the worst - it wouldn't start - and I got "brake system service" when I tried - and the brake pedal was solid.
Left it for another while - and it started fine. And has been starting since.
Its only when turned off for a short time that the problem happens.

Battery and alternator tested fine.

Any help badly needed and appreciated.

Will probably be the starter not happy. They get all contaminated internally with carbon from the brushes wearing....this causes high resistance when warm and the starter draws more current than normal. The battery may drop to under ~10.5 volts and this isn't enough to run the starter and engine & fuel system electronics...which equals...no start. When the starter cools down, the resistance is less and all is well with the world.

We see this all the time, a repaired or new starter usually sorts it.

Lord Knobrot

[sherwoodcycles]

If it wasn't this, another possibility could be similar - as I had something like this on a cbr600 motorbike.
It turned out to be the cam sensor. It was a lot higher resistance than normal (won't throw a code as does produce a signal (be it small)). But once hot, the signal was not enough for the ecu to read and it wouldn't start.


Only discovered it after going through the crude practice of changing things component by component.

[knobby1]

If it wasn't this, another possibility could be similar - as I had something like this on a cbr600 motorbike.
It turned out to be the cam sensor. It was a lot higher resistance than normal (won't throw a code as does produce a signal (be it small)). But once hot, the signal was not enough for the ecu to read and it wouldn't start.


Only discovered it after going through the crude practice of changing things component by component.

He hasn't been back since...so he was a "pop-in...pop-out"...possibly never to return.??

Lord knobrot

[jay]

check the earth strap under the seat