Vacuum port? - base of intake plenum?

[db9]

Poking around looking for G103 (ground point under intake) and spotted this - while I haven't run the engine to see if this is an open vacuum port (which would explain a low vacuum at idle @15 or so.. though I'd see 17+)

So I spotted this ... is this a vacuum port and if so what should it be connected to? Is there a vacuum line diagram somewhere as reference ..

[Mike W.]

Yes, that goes to the cabin temp sensor down by your left foot while sitting in the drivers seat. I believe it's supposed to have a flow restrictor in it to minimize the controlled vacuum leak, but I never did. IIRC it's a clear plastic tube, small, with the restrictor on the end by the manifold.

How's your idle? That's more of a test of vacuum leaks, the O2 sensor overrides things to correct the mixture for the added air, so idle goes up.

[db9]

Thanks Mike..
I'll look for the sensor and at the very least just cap the port for now.
The idle is good - not high or rough. The only thing I'm not used to is how loud the injectors are (when compared to my Forester, Dodge van or my SVT) not sure if this is normal or not - at some point I may post a video for feedback.

[Jetblue]

On my 533 that’s where my fuel pressure regulator’s vacuum hose attaches. My interior temp sensor attaches closer to the engine to the left of your pic. There’s also a third vacuum port under there as well that goes to the main intake hose. I can take a pic if that will help.

[db9]

JetBlue,
Any info is good info..
I'm getting the feeling that some of these cars are a bit of a free for all.. kinda like British cars (my old lotus was "interesting")

Is there a good vacuum schematic for the e28?

[Mike W.]

I'm getting the feeling that some of these cars are a bit of a free for all.. kinda like British cars (my old lotus was "interesting")

More like after 30+ years they're a free for all.

Is there a good vacuum schematic for the e28?

Probably not, because 533s, 535s, 528e's, M5s and 524tds were all a little bit different.

But something is probably for the model you're looking for, but more specific than E28s. Bentley?

[Jetblue]

http://blog.bavauto.com/8393/bmw-m30-en ... 5csi-735i/

Try this. I found this by using the search bar in the upper right corner. And awesome on owning a Lotus!

[db9]

JetBlue
Awesome !! I'll put it to good use.

Thanks
Yep the lotus was fun and interesting.. In the end it was sold after many years to help with the house, I alway look at the kitchen and think of that car

[Jetblue]

Here's the pics:



The Yellowish transparent hard plastic tube, just below the red starter wire fits into one of the blue hoses and then onto the plenum. I'm pretty sure I saw yours in your pic up to the right.

The black hose between the brown connector and single spade (with a red crimp) is the vacuum from the charcoal canister, which goes to a hose just below the brown elbow which the small blue hose feeds into.

[db9]

JetBlue
Thank for taking the time to take pictures..