New member please help

[stan080291]

Hello i am very amateur D.I.Y mechanic and I have an Audi A4 8ec B7 2006 TDI and it has the common P0234 turbo overboost code, I used a vacuum pump to check the actuator rod was moving freely which it does look to be moving pretty freely, tried using revive engine cleaner still there and it's also had a new n75 valve because the last one was faulty and the boost pressure sensor is working to the best of my knowledge, now I know I could strip the turbo down and clean it out but I did notice after connecting the vacuum pump to the pipe that goes to the n75 that the solenoid only pulled 5
Units of the vacuum gauge of the pump after starting the car to run to idle. Now apologies it's taken this long to get to it but my question is should an n75 valve pull more vacuum that this or does this sound about right ? Any help/feedback would be greatly appreciated

[VAG-Abound]

In general whatever the vacuum gauge reads when moving the actuator should be similar to what you see if the gauge is connected to the vacuum. What is a unit, so what does "5" represent? The pressure range that the actuator should need is documented somewhere in mm/Hg or similar.

Are you seeing and then clearing the P0234 code, and if so with what device? Does it come back when doing things like accelerating up an on ramp / hill, or straight away on a flat? I've had two of the "on a hill" types, even thought actuator seemed to be OK with a vac pump. One I fixed by making that car my daily drive with ~20 mins on motorway for a month or two. The other I put a replacement Mellet turbo on to ensure minimum time off of road.

[Crasher]

On those overboost is nearly always carbon buildup inside the exhaust housing, no amount of on the car cleaning is going to work for long.

[stan080291]

Hello Thank for your feedback apologies my question has not been explained very well, the unit is 5 inHg Vac that pulls when connected to the n75 valve, I have had the vacuum pump on the waste gate actuator to see if it moves freely and holds vacuum which it does both but that's it as to when the code pops up it's comes on whenever it feels like it I suppose

[stan080291]

In general whatever the vacuum gauge reads when moving the actuator should be similar to what you see if the gauge is connected to the vacuum. What is a unit, so what does "5" represent? The pressure range that the actuator should need is documented somewhere in mm/Hg or similar.

Are you seeing and then clearing the P0234 code, and if so with what device? Does it come back when doing things like accelerating up an on ramp / hill, or straight away on a flat? I've had two of the "on a hill" types, even thought actuator seemed to be OK with a vac pump. One I fixed by making that car my daily drive with ~20 mins on motorway for a month or two. The other I put a replacement Mellet turbo on to ensure minimum time off of road.


Hello Thank for your feedback apologies my question has not been explained very well, the unit is 5 inHg Vac that pulls when connected to the n75 valve, I have had the vacuum pump on the waste gate actuator to see if it moves freely and holds vacuum which it does both but that's it as to when the code pops up it's comes on whenever it feels like it I suppose