no problem anymore

 

Boost leak test????

 

we haven´t try that yet - but the turbo spools correctly. The BOV also works correct.

Do you think that this could be the error?

 

this thread should help you. but yeah do a boost leak test.
https://www.evolutionm.net/forums/ev...-backfire.html

 

how many kilometers on the wagon? ANY modifications on the car? boost controller?

1. boost leak test.
2. check ignition wires and coils , inspect them (look inside for any build up.

 

18000 km on the car - no boost controller.

the spark plugs and the coil were changed multiple.

Do you think the crank angle sensor could be defect?

 

IS the car stock? no modifications?

for the crank sensor. does the car starts right up?

 

The car is stock - only a catback is mounted. But it´s no fuel cut. We checked that.

The car starts good, but a few seconds after starting, the motor outgoes in idling mixture and i have to open the throttle a little bit. The idle actuator is also ok. (i hope you understand what i mean!)

 

AT what rpm's the engine misfire? when you hit the boost? check your vacum lines for cracks, near WGA and all the way from turbo/wga, to solenoid under the air box.

 

the misfires starts at 3000 rpm

 

we also checked the vacum lines - no damage

 

May sound obvious, but maybe a really bad tank of gas?

 

100 octane for a few times

bad gas is not the reason

 

could be, bad fuel mixture? - did you check the turbo for shaft play? also there are no code's as i was thinking maybe front o2 sensor?

but the worst come to worst, you need to inspect the head, and check the valves, where it shows low on compression, could be small bend on the valve.

 

So your saying that the timing belt skipped a tooth? Are you positive there was no valve damage? It seems odd that the compression is low in one cylinder and also that you found the timing off by a whole tooth and nothing happened. You would be lucky. If you already have things apart, I would pull the head and inspect the cylinder with the low pressure. You seem to have run down all the usual suspects, so it is time to dig in deep and tear her apart.

The usual culprits would be:
1) boost leak (turbo issue)
2) fuel (fuel itself, too) and/or boost cut
3) bad fuel pump or relay
4) bad injector or coil pack (spark plug included)

Things you have to now rule out:
1) Valve damage (springs included).
2) Piston/ring condition

Those are all I can think of off the top of my head. Your best bet is to pull it apart and see what is going on in that cylinder with the low compression. It is a tedious task, but might be necessary in your case.

EDIT: Also try the oil test. See if putting a little motor oil into the cylinder with low compression helps raise it up to the level of the other three. If this is the case you can rule out valve damage and narrow it down to the rings/pistons. If not, than you can be pretty certain that something happened to the head.

Hope this helps, and post up what you find!