TFSI Power Cut-out

[VVVWob]

Hello to all members,


For about one year, I am trying solve it and find what is the cause, but still without success.


On my engine 1.8TFSI (Audi A4 2009.) under high load, as WOT in mid range and for example testing in 4th gear at about 5000rpm on dyne, the engine cuts power completely and regains it in about 1sec (300-400rpm).





3rd gear on dyne looks like picture down, as you can see, what is very interesting, on dyne this happens only in 4th and higher gears, as said before, it has something to do with specific higher load on engine.







The engine is running on stage 1 map, that has been checked on a couple of cars with completely the same engine as mine (dyno graph on tuner's site )
The car is showing no fault codes or any other error in memory, it has about 100k miles and is generally in very good condition, except from this.
Turbocharging systems (turbocharger and all other hoses, n75,diverter value eat) has been all renewed by dealer, because of some other problem some time ago.


This immediate drop in power (actually two times), as display on graph, occurs in 4th on dyne always at same rpm spot (about 5200rpm)


I have been doing many logs in VCDS, but everything seems to be OK, and in the range, I mean the ECU isn't showing any error.
At the time of this drop (on dyne and some time in driving) everything is cut down, fuel consumption goes very low, ignition timing also, a/f is very lean etc.
ECU is for some reason cutting down everything and in the same way building it back, without any message.


Until now, I have changed LPFP (plus fuel filter), tried HPFP form friend (same OEM number), spark plugs renewed.


After all this, I don't have any idea what could possibly cause this problem, my concerns now are maybe coil packs, rail pressure sensor, knock sensor or OEM new HPFP.
But, as explains before, everything of these thing doesn't make sense to cause this huge problem, as the cause for so big reaction form ECU.


I would be really grateful to all of you for any advice/help regarding this situation.
Thanks in advance

[sebgreen]

Going to be very hard to diagnose without any errors being thrown.


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[VVVWob]

Of course I know, I am into this more than one year.
I asked weather someone could make some conclusion about all those control parameters and fact about no fault etc.

[sebgreen]

If it only happens in a certain gear, check out the gearbox.


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[VVVWob]

The car has manual transmission, the clutch in this case could hardly make any problems at the point where TQ is far form maximum and also that would last less than 1 sec, Ithink at least.

[sebgreen]

The car has manual transmission, the clutch in this case could hardly make any problems at the point where TQ is far form maximum and also that would last less than 1 sec, Ithink at least.

But it is fine at the same revs in other gears? The only element in the problem that is unique is 4th gear.........


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[VVVWob]

It happens at all higher gears 4th 5th for example, this is dyno graph, even less would the clutch be possible to make this "sharp dip". Clutch, transmission problems look far different and have feel also in more cases with some other symptoms.

[sebgreen]

Friend of mine had an issue with power loss at night revs on his manual tts. It only effected 3&4. Was a gearbox issue but it was reporting errors.

So you are in a higher gear at higher speed. So driveshaft and wheels moving. Wonder if it is vibration or something.


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