Low N75 duty cycle and hesitation - why?

[tonipieleanu]

The main problem I have is hesitation when changing gears and leaving from a stand still. As soon as I let go of the clutch the rpms drops and get a hiccup then it revs almost as it should. The same happens when I'm changing gear.

MAF, O2 sensors have been replaced but the problems still exists. Found a couple of vacuum hoses rotten, the one to the FPR and the one to the combi valve. Also replaced but I'm still having those issues.

While doing some logs I've noticed that my N75 duty cycle is low. Even at low revs, like 2500rpm at WOT, my duty cycle doesn't climb above 60% and keeps this value to the red line.
Pressure is reaching the requested valued, but I belive it does this slower than it should. It's like the turbo isn't even trying to boost faster.

Could this cause my driveability issues?

 

[tonipieleanu]

Tonight I've removed the hose from the N75 to the wastegate, so I was running full boost all the time. Had to drive gently but from I've felt, the car ran better. Hiccups were diminished when letting go of the clutch and changing gears.

What could this mean? Could the hose from the turbo to the SMIC be shot? Have a crack or something?

 

[turbin]

get a new N75 unit. Sorted

 

[tonipieleanu]

That doesn't make sense.

The ECU command for the N75 is wrong, not the valve. The ECU wants 60% duty cycle, that's what the N75 does. If I was having 95+% duty cycle and my boost was low, that could have been bad valve but in this case it's not.

 

[turbin]

not my field.. ull probably get a more qualified answer form someone else. Sounds like you need a vag-com and do some testing.

 

[Lodgey180]

have you checked all your piping for splits.. also a few octavia vrs;s had problems with the one way valves in the vac pipes..

 

[tonipieleanu]

I'll be checking with a mechanic in a few days. I'll check the one way valves too.

Any other suggestions or things to check while the car is on an a ramp?

 

[m0rk]

is the car remapped?

 

[tonipieleanu]

Nope, it's stock. No engine related mods (just wheels and suspension).