Start problems when engine is warm ?

[Corre 0]

Hi! I´m new to this forum, and would like to say hi to all members My english is not good, but i hope its good enough for you to understand me :)

 

Anyway, i have a problem someone maybe can help me with When starting my engine when its cold, i have no problems it takes 1-2sek only. But when the engine is warm i have to keep crank the engine for about 5-7 sek before it starts!! IF i depress the acc pedal when the engine is warm it starts much easiser...! But should i really need to touch the acc pedel when starting ?

Any ides where my problem can be ? The car is a Corrado Vr6 -94.

 

Many thanks in advance !! :)

[Cnut 0]

It is probably fuel vapourisation caused by the fuel pump not running on after the car has switched off

[Corre 0]

Cnut:

 

But why does it only happend when the engine is warm ? never when its cold ?

[Supercharged 2]

Corre, wlecome to the forum!

 

Does your fuel pump run on when the engine is off?

[Taggart 0]

Because it's the heat from the engine causing the fuel vapourisation?

[Corre 0]

Supercharged:

Does your fuel pump run on when the engine is off?

 

How can i know that ?

[Supercharged 2]

You should hear it from under the cover in the boot - you will also hear the radiator fan at the same time...

[Corre 0]

Supercharged:

 

Yes, the radiator fan starts when i stop the varm engine, and also the water pump! But the fuel pump i can only hear when i turn the ignition ON with the key! Could there not be any problem with the O2 sensor ?

[Supercharged 2]

Ok, it's aVR6 then if you have the aux waterpump - you should hear the fuel pump run on also...

 

Are you sure it's not - place your hand over the fuel pump cover in the boot and you should feel it, even if you have a very quiet pump...

 

If it's not running on then you may have found the fault!

[.Rich. 0]

i have this problem with my valver, same diagnosis?

[Corre 0]

Supercharged: YEs, its a VR6.

 

But why should the fuel pump be ON when the engine is off ?

 

Thanks alot for you help :)

[h100vw 0]

It circulates the fuel around the lines to prevent it getting vapourised under the bonnet.

 

If it vapourises in the line by the injectors, there will be air there. It'll take a good few seconds for the pump to push fresh, cool, fuel through the system.

 

The aux water pump has the same function. It keeps the water moving in the block, the VR is a compact engine and creates plenty of heat when running. Pump the water round after shutdown prevents heat soak.

 

GAvin

[NickRStorm 0]

FWIW, I have always had this same problem on my Golf VR6 (but not on the Storm) & kicking it over for a second then turning it off & trying again always gets it started instantly. The problem only happens for 15 to 60 minutes after stopping.

[Supercharged 2]

This problem may be caused by an alarm/imobiliser badly installed so it's affecting the fuelpump run-on circuit.

[Corre 0]

Supercharged:

 

Yes, maybe.. because i have an aftermarket alarm and imobiliser installed. So 5min after the car is shutdown, the imoboliser is ON!

[buttles 0]

Just dragging this back into the daylight! 94 VR6, which circuit controls the fuel pump run on system? I have not armed my alarm/immobilizer deliberatly to make sure it does not interfere with the fuel pump and it still takes ten or so seconds for the car to start from hot when it has been left for just over ten minutes. Does the fuel pump run continuously whenever the engine is running and for how long after the ingition is turned off? Don't think my one runs when the key is turned off. Thanks in advance!

[ReekieVR 0]

Yo - i have the same problem. It only started 6 months or so ago. I'm sure the fans used to run on, but they dont now - i thought i was imagining them doing that. What would fail in the 'run-on' circuit ? Are the fans, fuel and aux water pump run-on all on the same circuit? How do i test if the fuel and water are staying on after ign off

 

If i try to start the car hot, but leave the ign on for 15 secs before final key twist, then any vapour would be flushed out and it should start as it should, no? Will try it tonight.