boost lag and fuel economy question

[newsh]

Maybe something got dropped down the downpipe?

[hunker7]

No, though when I had it on a lift, when banging on catalyst it did rattle :/

[newsh]

No, though when I had it on a lift, when banging on catalyst it did rattle :/

Ok, well, unplugging the N75 reduced max boost to 1.4 so we know the ecu is requesting boost and the N75 is working

So as error says we're probably looking for a mechanical issue, a blockage or some kind of contained boost leak, like the DV being open all the time or the PCV plumbed up wrong.

Just check that the PCV breather pipes are connected the right way round on the back of the cam cover and the manifold.

[hunker7]

I think there is a bolt on downpipe that I could take out, remember doing this on my V6 to check blocked exhaust .

I'll check that out actually.

Ok, well, unplugging the N75 reduced max boost to 1.4 so we know the ecu is requesting boost and the N75 is working

So as error says we're probably looking for a mechanical issue, a blockage or some kind of contained boost leak, like the DV being open all the time or the PCV plumbed up wrong.

Just check that the PCV breather pipes are connected the right way round on the back of the cam cover and the manifold.

I used Dave's diagrams to hook it up, but I guess it won't hurt checking it. I will check DV whether it's split it or not. If not I will remove the bolt from downpipe and take it for a loud test drive

[simons2]

If you have lined up your cam timing Mark and cannot see your flywheel tdc Mark in the bellhousing window then the timing is out

[Jack4688]

If not I will remove the bolt from downpipe and take it for a loud test drive

Do that anyway Endless fun

[mike74]

One other thought, have you ever had the wastegate apart to check the piston moves freely & that the diaphragm isn't split?

[newsh]

If the WG diaphragm was split you'd be getting excessive boost.
WG could be jammed open though.

[hunker7]

I only removed the cap, painted that and put back together. There were no rips in the diaphragm. It was moving pretty freely.

[newsh]

Did you get the perch back on top of the spring?

[newsh]

I guess so or you wouldn't even get 0.4bar with the N75 unplugged...

[hunker7]

Been thinking back to it, and I'm sure everything has been assembled correctly. I will check timing tomorrow possibly, but I'm sure that is fine.

[bertman]

Excessively worn stems on the wastegate valve have been known to stick,can be worth taking the wastegate apart and checking the stem to see if there is any wear.They can be rotated so that the wear is moving on a different area of the stem

[hunker7]

It was moving freely when I had it apart.

[Thecrispynoodle]

You mentioned temp gauge shows 100 earlier, suspected due to a bad thermostat- is that fixed yet? 100 is high and ecu may limit both timing and boost as a result. When ecu pulls timing it's most noticeable off boost and will make onset of boost feel later. It's also rare for thermostat to fail in way that makes car run hot usually they fail open and car runs cold when moving.