VW Passat 1.9 TDI LESS Boost

by **Jannik07** » Mon Aug 02, 2021 6:37 pm

Hello everyone,

A friend of mine has a passat 3b with the 101hp PD engine.

Today we tuned it a bit and he also wants some smoke.
The problem we were facing is, that it makes a lot more boost than it should do!

In the Boost target map i wrote 1800mbar for the last column but it does up to 2600mbar absolute.

WHY ??

I also checked the n75 valve with vcds and everything is working great in my opinion.
Maybe someone can check the file?

When I log it the requested Value is right, but the actual is not in the wanted range.

Thanks in advance!

by **ceecee** » Tue Aug 03, 2021 11:02 am

It could be stuck vnt.

by **Jannik07** » Thu Aug 05, 2021 8:26 am

Yes thats true, but when I Do the n75 test in basic settings the boost rises or falls. So the vnt must be working or Not?

Greetings

by **ceecee** » Thu Aug 05, 2021 1:57 pm

Not really, with temp and pressure changes it could get stuck sometimes. You can check with engine hot after driving, stop engine and try to move vnt with hand or some util aprox 1cm, if ok well it could be other thing, if stuck you found it.

Check all vacuum system (tubes, n75 or valves box etc). MAP can be too.