Fuel pump long run when power on w/o start

[CMF_niilo]

Had replaced fuel pump & fuel regulator, but still,
fuel pump runs long every time I turn ignition key on (w/o start so that I can hear it).
As my experience is, normally in K11 this not happen usually, which means that the fuel pressure in fuel line is not staying.

So the questions are :
1.) Is there some "return-valve" in tank keeping pressure in fuel line. Looked to the tank when changed the pump that the return-line is connected with hose to some point in bottom of the tank, but no idea about what is on the very end.
2.) Does the fuel-regulator in injector-common-rail play any role on this ?

 

[CMF_frank2]

the pump should only run for about 5 secs niilo, then the ecu cuts it off if there is no cam sensor signal

 

[CMF_niilo]

Thanks frank2.

Need to clarify that pump was run that about 5sec. even w/o tryin to start engine - only ignition turned on.
Referring to another micra about same age which do not run pump even on every start - which I assume means the fuel-line keeps it's pressure between starts.

So do you think this is not pressure-related issue and ECU just runs that time in each ignition-key-turn-on ?

Th thing why I am trying to solve this is that in on engine start its not clear and fast. In start engine is "wobbling" and starting slowly (and do not start if not pressing gas-pedal) which made my think about fuel-line pressure.

Any other ideas what to check ?

 

[CMF_frank2]

yes the ecu controls it mate, does the car run ok ?

 

[CMF_azman89]

Niilo,
This is normal operation on 99% of fuel injected vehicles. The ECU primes fuel pressure for a few seconds when it receives ignition (as Frank kindly explained above). This is not pressure controlled. The ECU, in most vehicles, never even knows what the fuel pressure is. So it has nothing to do with it holding pressure or not.
On a side note, yes there is a valve that is meant to keep pressure in the fuel rail. It's located in the fuel pump and is a non-servicable item.

 

[CMF_niilo]

Ok.

As my experiences are from -93, -94 and -00 models, they seen to handle fuel-pump differently.
In this oldest model heard this 5sec. run, but not on the others.
That made me think about issue on that.

I suspected failure in old pump because it sometimes run on start that 5sec. and sometimes not.
I had almost used pump in my garage picked up from the other Micra which I installed instead few days ago.
This later installed pump always run 5sec.

Ok. But thats now throughly discussed.

Thanks guys for giving info.