Euro 4 boost system, how does it work

[GrahamBrown1]

I've got boost issues with my e4 2.4d. With it having an electric variator on the turbo am I right in thinking the vac system on these has nothing to do with the turbo and is just for the mounts ect. There are vac lines going to the egr what do these do?

Thanks

[5cilinder]

Yes the vacuum system has nothing to do with the turbo on euro 4
The hose going to the egr is for the egrcooler bypassvalve its active during warming up it bypasses relative cool exhaustgas past the cooler until the engine is heated up

If it goes leaking it also affects the mounts during warming up

[GrahamBrown1]

Originally Posted by 5cilinder

Yes the vacuum system has nothing to do with the turbo on euro 4
The hose going to the egr is for the egrcooler bypassvalve its active during warming up it bypasses relative cool exhaustgas past the cooler until the engine is heated up

If it goes leaking it also affects the mounts during warming up

Thanks,I'm going to plug into vida but not been familar with the euro 4 system I just wanted to check. Do you have any ideas what could cause poor boost on the e4. Do the electric units on the turbo give much trouble? Inter cooler looks ok from the outside no oil residue ect and the pipe work looks good.

[5cilinder]

The electric vnt is not known for issues
If there is a problem a troublecode will be seen
What kind of codes did you have?
(maf performance is an indicator for a major leak)

Just looking at an intercooler isnt sufficient , you should pressurise it and listen for leaks
Tip: take the lid from a shaker or drinking flask put a hose with a clamp on the mouthpiece then put in the rubber hose connected to the intercooler secure it airtight with the clamp you loosened to get it loose
Put a unopened cokecan in the other side and secure it also airtight
take a bicyclepump and pressurize it and listen for leaks (even a small leak will be heard)

Also the pipe under the car is vunerable for roadbumps to split or the seals on the silencer or connected to the turbo can tear and wear (had it myself)

[GrahamBrown1]

Thanks for the tips, turned out to be dirt in the maf sesnor. All cleaned up and cleared codes and looks to be running ok again. Now fault codes returning ect.

[5cilinder]

How did that dirt get there? Check your airfilter for tears on the seal edge

ps

You can also calibrate the maf sensor in vida

Under ECM advance tab

[GrahamBrown1]

Air filter is changed Regular and I allways Hoover the air box out but it was caused by the glue or the bonding material that helps to seal the maf sesnor to the air box lid. It has turned to a yellow dust I guess with heat cycles and age. So cleaned up and blew out and as you say I re adapted the sesnor in vida and all seems to be fine now.