Vacuum hose replacement questions

Gents,

Still learning here and got supremely confused and figured out while doing that not all E46s are not the same when it comes to vac tubing lol. Mine is a 2003 w/ manual transmission.

I was just about to start my VANOS rebuild when I started to have an on again, off again issue w/ the front 02 sensor going off. So I bought two pre-02 sensors. I also had planned to refresh the vacuum tubes...but unfortunately I started to watch a lot of YT vids where they showed other non-ZHP procedures to remove the Vacuum control valve, check valve, replace vac hoses, etc. So I was going in with that mindset that I needed to do all of that, but discovered today that those 3 male ends behind the right side of the intake manifold were capped off. On another note, that BMW designer should be slapped for putting them there. For future readers of this thread, here's what I'm talking about:

https://i.imgur.com/wt7sRG7h.jpg

Well, that saves me some work so that's a good thing. The larger plugs (BMW-11611727176) is still in good shape with a tiny tear, but I have a new one on the way. The 2 smaller plugs (11611437560) were in fine shape, but I decided to replace them with 5/32" auto vac plugs that I had on hand. I'm glad our ZHPs dont have that VCV, looks like a b___ to get off due to lack of hand space. I noted too that there's no more vac hose from the secondary air pump valve (think that's the name---on pass side near the big secondary air pump) to change. Good.

So please check my understanding here. The remaining vac lines / hoses to replace on our ZHPs are:

Thinner vac hose ends from the F-elbow to the fuel pressure regulator
Thicker hose from the F-elbow to a Y-junction that continues downward to the intake
Thicker hose going to the brake booster

Of course, the PCV is on the list but it appears that the PO's former mechanic changed it out at 80K and I'm at 99K.

Gents as always, I appreciate any answers (pics are a bonus), links, etc.

The difference is MS42/43 vs MS45.x engine management, not ZHP vs non.

On early cars, the secondary air non return valve is opened via vacuum, so you have the solenoid valve pictured that allows vacuum to reach the valve.

On later cars, the secondary air non return valve is opened via air pressure from the pump, so there is no need for the vacuum system like the earlier cars.

Thinner vac hose ends from the F-elbow to the fuel pressure regulator
Thicker hose from the F-elbow to a Y-junction that continues downward to the intake
Thicker hose going to the brake booster

This is correct. Also note the hose going to the fuel pressure isn't to apply vacuum to the FPR, its to catch any fuel from spilling if the FPR diaphragm fails and leaks.

George,

I appreciate the education on the differences and purpose of the fuel pressure hose.

Bob