Issues starting when hot/long run

[Jakehands]

Having some strange issues with starting when hot or after a long run, was advised of cam sensor when i bought it so i replaced that, have done both? Coolant temperature sensors (1 under throttle body other on the bottom rad pipe) done this because fan was not kicking in and thought that may be the issue, its not overheating (to my knowledge) its had a new thermostat when i done the front engine pipe water pump seems fine have hot and cold air, done 109 relay and ordered a 53 relay to test, i did buy a cheap cam sensor and it starts up faster when unplugged, (read the posts on here) bit stucl pf what else it can be, it doesnt cut out when driving (done 250 miles the other day) stopped at the end to get food and it decided it didnt want to know, im going to order a new ecu reader and fault find just wanted some input of what it can be. Many thanks

[SirDavidAlhambra]

Fuel pump not delivering enough pressure when fuel is warm or injectors letting in too much fuel when engine is hot possibly?

Maybe put a bottle of redex through it and see if that helps?

[brianh]

Define didn't want to know please
- Does it try to crank but fails to fire up, or fail to turn over?
- Does the LED on the drivers door do anything different when it starts vs when it won't?
- When it does start after the problem occours, do you get clouds of smoke or does it seem to start on only some cylinders, or does it fire straight up as normal?

Relay 109 type issues can have other causes,  what exactly have you done? Replaced the relay with another one from ebay? New one? Resoldered the joints? Note that relay 109 issues usually cause the door led to flash rapidly, and diagnostics usually won't connect when the fault occurs either.

Anything added to the fusebox? The fuse on the bottom righthand corner can appear ideal for a dashcam fuse tap to be installed as it switches in the desired way. But it also will cause the engine to die if contact across it is lost and give the relay 109 type symptoms in exactly the same way.

[regw]

CKP ( Crank position sensor)  maybe?
Some have been known to break down when hot causing similar problems
My lads Merc deisel had this and a new one fixed it

Getting fault codes would be a good place to start though

[Jakehands]

Ive ran redex through do this every other tank or 1000 miles aswell as add oil if needed, i did think about this and there seems to be fuel going through the filter when it does decide to fire it runs fine. It will just crank and crank and crank, until i disconnected the cam sensor then it fired up after 2 attempts.have not checked the door led but will as i know that may lead to immobiliser but would that kick in when ran (short journeys never bother it) no smoke or oddities when it does kick in literally like its malfunctioned and gone back to normal. i bought a brand new relay as i didnt want issues with refurb/preowned nothing added did change the 2 lower aux fuse box fuses as both had minor corrosion. Yet to check/replace CKP as thought id resolved this earlier with getting the fan to kick back in lol

[johnnyroper]

As above can you define didnââ,¬â,,¢t want to know better.
Was it spinning over and not firing or just not turning over?

If spinning over and not firing thatââ,¬â,,¢s classic symptom of cam sensor,as it was a cheap one as you say I would look to fit a proper OE one (think they are Bosch)

[johnnyroper]

Ive ran redex through do this every other tank or 1000 miles aswell as add oil if needed, i did think about this and there seems to be fuel going through the filter when it does decide to fire it runs fine. It will just crank and crank and crank, until i disconnected the cam sensor then it fired up after 2 attempts.have not checked the door led but will as i know that may lead to immobiliser but would that kick in when ran (short journeys never bother it) no smoke or oddities when it does kick in literally like its malfunctioned and gone back to normal. i bought a brand new relay as i didnt want issues with refurb/preowned nothing added did change the 2 lower aux fuse box fuses as both had minor corrosion. Yet to check/replace CKP as thought id resolved this earlier with getting the fan to kick back in lol

I think you have answered own question there, cranks and cranks and cranks but fires up quicker with cam sensor disconnected.

[johnnyroper]

Also when cam sensor is breaking down causing issues like this it does not tend to trigger a fault code for some reason,mine certainly didnââ,¬â,,¢t. The reason why they start with it unplugged is ECU disregards the cam sensor and works of crank sensor for starting. I seem to recall due to the unit injectors and way they operate ECU uses cam sensor for starting so it knows precise position for firing the correct injector.

[Jakehands]

Okay thank you and yeah it just cranks over several times (leisure battery in it for some reason) ill order a new not cheap sensor and hopefully that will sort it out, i will update once fitted to see of that solves it