fuel cut at full boost...? why?

[topsparky]

also try the lambda sensor mate
mine did this
upsetting an m3

[driftin jo]

also try the lambda sensor mate
mine did this
upsetting an m3

It can't be the lambda sensor as it's signal is completely ignored by the ECU at WOT , in fact it's even ignored under moderate acceleration, it is only used for cruising and idle.

[rs200]

no ... the lambda probe is 100% OK..and it is not possible, because when lambda is off , car don't work like it have to be..

maf or boost leak, but I'm 95% shure that is boost leak under the intercooler , because the flange is not OEM..

we will find out... thanks guys for help..

[rs200]

again I had fuel cut problem , but now they came even at not WOT.
normal crusing at 2500rpm and fuel cut. there is no fault codes or boost leek. they can easy produce 1bar. I also did boost leek test. and everithing is ok.
what else can cause fuel cut?
tnx
Igor

[prj]

Check grounds to the ECU.

[rs200]

I alredy did.. it have it.
it is very strange. there is no fault code or filure which I didn't have on that car in 7 years. it is cursed !
let start from begining.
before one week I changed valve cover and intake manifold ADU-3B , and put rs3 coils. car bun fantastic on idle. then went to drive.
fuel cut , engine check , ISV, clean them .
ride again, fuel cut - RPM sensor, I change them too. now there is no fault code , but fuel cut still exist.
in middle time , I clean MAF, look for ECU ground, done boost leak test, look all fuses, everithing is fine, but this fuel cut ...
my mind will blow !

[prj]

You have bad grounds on valve cover / inlet manifold.

Or you bought B-grade coils, not BERU or Bosch. They will give interference to RPM sensor and ECU will restart.

Use only Bosch or Beru.

[rs200]

they all are OEM VW from golf 5 gti. and work grate on idle.. could they make problem on other revs?
they are OEM !

[rs200]

also I forget to said, that fuel cut is not all time, for exemple:
drive in 3. gear normaly.. and than WOT, full boost is reached, than fuel cut, emediatly after that I put in 4. gear and again WOT, full boost , and nothing , 5.gear WOT and nothing.. everithing is fine.
than everithin was fine 5 minutes later in normal drive fuel cut.. very strange . sometimes is good at WOT, sometimes not.

[driftin jo]

also I forget to said, that fuel cut is not all time, for exemple:
drive in 3. gear normaly.. and than WOT, full boost is reached, than fuel cut, emediatly after that I put in 4. gear and again WOT, full boost , and nothing , 5.gear WOT and nothing.. everithing is fine.
than everithin was fine 5 minutes later in normal drive fuel cut.. very strange . sometimes is good at WOT, sometimes not.

MAF connector, when mine did this, it was the connector.
The fact that it does it intermittently suggests it is more likely an
electrical problem than a boost leek, especially as it does it
when not at WOT.

[rs200]

of course.. it is electical problem.. but where? everithing seems ok, even MAF conector.

[UrS4boy]

of course.. it is electical problem.. but where? everithing seems ok, even MAF conector.

"Seems ok" could just mean that you haven't investigated it enough and are missing the problem. Check and clean the pins (both male and female). Check the pins for being pushed out of position. Clean the MAF wire. Substitute a known to be good MAF and re-test. Then and only then can you say it isn't the MAF. Even then, it could be a wire problem between the MAF and the ECU.

More MAF info:

http://forums.quattroworld.com/s4s6/msgs/20442.phtml

[prj]

You will throw codes for MAF connector.
I am pretty sure it is not fuel cut, but it's the ECU losing engine speed sensor signal or power, so it misses.

Most likely the ECU clicks as well during this.
Any "fuel cut" software wise will have a "Maximum boost pressure exceeded" code logged.

If there is no such code, it's not fuel cut. End of.

[rs200]

you are right Dmitri.. there is only engine speed sensor problem, and it is not fuel cut.
there is something else , MAF is perfect.
probobly it is the problem. where I have to look?

[prj]

If the problem started with the coils, and you made a plug and play loom, try to change to old coils temporarily by plugging the old cover back in.

If that fixes the problem, then the problem are the coils or the wiring to the coils.

If that does not fix the problem, then it can be bad grounds, bad trigger sensor or bad ecu.