320d e46 bad boost behaviour

[FerdiBotha]

Hi all,
I'm hoping and praying for some good advice as I'm pretty much out of ideas as to where to from now. My 2002 e46 320d (manual) seems to have a boost bug of some sort. Low down boost only comes in at around 2250rpm (if I'm lucky), but mostly around 2500rpm). Once it starts boosting it goes pretty well, especially in 1st and second gear, yet it doesn't seem to boost through to anywhere near the redline. In 3,4,5th gear it boosts just as it pleases. Boost comes in and then disappears and then returns for a brief moment before there's no boost at all anymore. When I drive well into the boost in any gear and I shift gears, the car has no boost for a second or two before boosting again. This is my second 2002 320d, so I know how the car should behave and this car is nowhere near the previous one in terms of power, fuel consumption etc.

Any advice would be appreciated.
Thanks guys.

 

[DieselFan]

Vacuum leak maybe?

Sent from Samsung S5

 

[FerdiBotha]

Hopefully something minor like that. It's currently at a workshop (for the second time), hopefully they'll sort it out.

 

[M3_devil]

Your pressure convertor could be cause aswell.

or also known as boost solenoids. Controls vacuum being applied on your wastegate.

I had lag issues and wavey torqe curve.

Search for post under x35 section for vacuum solenoid.

not saying it is same issue but worth checking out

 

[Hellas]

+1 on the vacuum related problem.

First carefully check all vacuum hoses for perish and cracks. On a 2002 model if they have not been changed, you can just as well change all of them now. Buy 5m or so and start snipping.

Further swop out the vacuum actuator from the EGR and the turbo, they are the same. then check if the turbo's vane actuator (the little plunger arm on the turbo) moves when you start the car. It should pull in, then slowly release after starting.

 

[netercol]

either the control system (like already mentioned above) the actuator, vacuumlines, or vacuumtank..

or simply sticky or stuck vnt vanes in the turbo itself, or faulty vnt actuator..

not very much else it could be..

 

[ChefDJ]

+1 on vacuum lines.

 

[FerdiBotha]

Thanks guys. I will make sure the vacuum lines and actuator gets checked. Hopefully I'll have it sorted and be able to give some feedback asap.:thumbs:

 

[billbt]

I had a problem last month with my turbo boost coming in and fading then coming in again, boost was very erratic!!! Took out my MAF sensor and cleaned it with MAF cleaner. Car pulls like new again, hope this helps.

 

[FerdiBotha]

So the car has been back twice with them telling me it is now "fixed" every time. Next game plan will be to check the maf sensor and the egr. Really not digging this.:bangdesk: