what temp is vagcom reporting?

not the dashboard gauge

for it to force itself rich it must be seeing a very cold tempetature or false reading from the lambda so if vagcom is reporting a sensible temperature in measuring blocks then I would try another lambda probe in it.

or the other things could be

blocked airfilter (maybe sucked a plastic bag in?)

blocked up catylist or blocking up exhaust (does it whistle when you try to rev it)

a squashed fuel return pipe from the engine to the tank or faulty reg (which is very very rare)

In VAG-Com it's reported corectlly.

10*C when starting the engine ( 5*C outside temperature) and 93*C when engine is warm (and rough running).

I opened catalyst and left engine running, so I can tell if it is clogged. I realized that it is not clogged / blocked.

Exhaust back box, was changed six months ago, assuming it's not clogged.

Airfilter is also ok.

I will check fuel return pipe.

Edited 28 December, 201213 yr by XphaN

have you tried a different temp sensor and have you checked thermostat do you get a clicking noise up near the charcoal filter thats the Charcoal Filter Solenoid Valve and this forum has helped me out loads and i would not off been able to convert my car to a 1.6 aircon spec

Edited 28 December, 201213 yr by uma1998

Thermostat has nothing to do with my car problem.

Hello and Happy New Year! I checked gasoline return pipe (after the pressure regulator) and found that, with the ignition on and engine running (either hot or cold engine) will not run any bit of gasoline. Fuel return hose is not clogged.

Maybe a N80 sensor faulty is causing this problems? With the engine running, I sat beside him 5 minutes trying to hear any clicking-sound, but no sound was heard.

What should I check next?

Now fuel consumption is about 10L / 100km

Edited 6 January, 201313 yr by XphaN

The n80 valve does not affect fuel mixture, it is there to let the vapour from the fuel tank Into the intake.. It should only work when the engine is hot, and idling, and running in closed loop mode.. We've already worked out your engine is not running closed loop so this system will not function anyway.

if your fuel return line as no gasoline flowing then there must be a blockage in the fuel rail or pressure regulator.

yes.. What he said..

on that binary readout above the very last digit on the right relates to the coolant temperature sensor.. There's something fishy going on with it, there should only be a 1 there if the temperature is over 80 degrees celcius, which is also a condition of closed loop running

it would appear the the throttle body is functioning correctly as well as the lambda probe judging y the various operating conditions you state above.... I think that the coolant sensor is reading incorrectly.

Checked in Haynes manual (meaning of the digits in the 8-digit numerical block Group 01) if the last digit is 1 the temperature is < 80*

Assuming that, the temperature sensor is reporting correctly.

Checked yesterday fuel pressure from fuel pump and I got a maximum of 1.7 bar

Edited 8 January, 201313 yr by XphaN

I think it should be 3 bar? I seem to recall that's what mine was as standard, and it was definitely what the rally car was running when modified...

Edited 8 January, 201313 yr by djaychela

yup ... the fabia run on 3 bar too ... If I were you I would change the pressure regulator with the filter. It sounds like it is malfunctioning after a short time of operation. It is cheap too if it is like the fabias. It looks like the rail is working in much higher pressure that it should be working and the ecus trims aren't large enough to stop enrichment.

The reading from the pump directly does not sound realistic. This reading would be the pumps total head pressure and for sure it would be much higher than 3 bars.

check was made at the hose from fuel pump, one who enters in fuel rail

TeflonTom

How did you recognize that the engine is running all the time in open loop mode?

Right, so you have just 1.7 bar between pump and engine yes.

and NO fuel coming through the return pipe with the engine running ?

the pressure reg on the rail is 3 bar which means that until it see's 3 bar of pressure at it there will not be any flow through it so you either have a blocked filter or the pump itself is broken.

try a filter first as they get a bit neglected due to where they are fitted or try measuring the pump pressure directly from the pump before the filter.

I have seen the flexi pipe from the pump to the tank outlet split before which meant the pressure was very low but still ran.

I replaced again the fuel filter yesterday with a new VIKA one.

In respons to your question, only a few drops of fuel at the return pipe, after the fuel pressure regulator..

Edited 8 January, 201313 yr by XphaN

Adurer are sure your that haynes manual is for an MPI engine? My pump did not look like that from the pictures. According to my haneys manual the pressure measured before fuel rail must be at minimum of 3bar

Can lamba probe give incorrect information about a rich mixture and ecu is struggling to keep another mixture? Maybe a lean one? I am thinking about this because a rich mixture will not cause misfires in inlet manifold and will do a black smoke at exhaust.

If I run with lambda probe disconnected the engine works a little bit smoother but not like it should.

Finnaly got it. Ecu negociates air flow all the time. So after the coolant sensor is sending 90*C value to ECU this is trying to keep a good mixture, but because the fuel pressure is too low, it can't maintain a good mixture and this is too lean, resulting loss of power.

So, i need to change fuel pump.

Thank you all for your support.

Edited 8 January, 201313 yr by XphaN

yes looks like you have it there mate.

Was a little hole in fuel pump.

I put a screw in that little hole, and now the fuel pump is working well. Fuel pressure is about 2.3-2.5bar all the time.

Erased all errors in VAG-Com and now car gets more power in all gears.

Thank you all for your patience and help.