Poor warm starting S2 ABY

[hermanio]

i have a problem with my s2 ABY, when the engine is cold it will start fine. when its warm it will also start fine, but when the car has sat for let say half an hour, its much harder to start the car. i cleaned the injectors but it didnt help, checked the G62 temp sensor with a multimeter and it was fine. does anyone know what can cause this problem ?

[Jamo]

Hall sensor is on it's way out and needs changing. Common issue on ABY be careful it will get to the point where it wont start at all when warm.
If you do get stuck you can try the cold water down the cam cover trick

[hermanio]

forget to say, that was the first thing i replaced, didnt help..

[hermanio]

the strange thing is that i only have the problem when the car has cooled down a bit, when its warm ist start fine. i thought maybe my fuel injectors were leaking when i shut down the car, but cleaning them didnt help. you should say its a fuel issue because when i try to start the car i seemes like the car gets to much fuel, a little trottle will help then but it still wont start like it should

[hermanio]

also no fault codes

[Monkeymagic]

Possibly leaking injectors causing engine to lock up a little? I suffered a hot start problem with my MK2 Golf for ages after a 2 litre conversion changed all manner of things. Turned out to be the negative battery terminal to the block going high resistance when hot. Changed for a thicker one and never struggled since.
I'm no expert with S2's but is it a possibility?

[hermanio]

thanks for you reply but i dont think thats the problem, because when the car is hot it start fine. only when you wait for half an hour it doenst start good, like the mixture is to rich

[Monkeymagic]

If it's struggling to crank over i would suspect injectors leaking. Try recreating the problem but remove the plugs.

[hermanio]

i made a video of the problem, car is warm and sat for half an hour. when the car start you can hear a bubbling sound for the tank, you can only hear this when the car start bad.

[driftin jo]

Maybe your check valve is dead.
If so the heat would make you loose pressure when you shut off .

[driftin jo]

You could check if it this by running the pump for a few seconds
before trying to start it, just run a wire to the pump.
I fitted a push switch as when i fitted an aftwrmarket
pump it had no check valve and i had similar issue .

[hermanio]

check valve is at the fuel pump isnt it ? pump is cooled by the petrol so would heat effect the valve ?

[driftin jo]

Heat will help push the fuel back to the tank if the tank check
valve is no good

[hermanio]

ive tryed running the fuel pump for a few seconds with a cable before i start the engine, but there was no difference

[driftin jo]

ive tryed running the fuel pump for a few seconds with a cable before i start the engine, but there was no difference

it's not the check valve then, at least you have ruled that out.