bmwe21.net forums

Hello everybody!
I've been a 323i owner for over a year now and considered to join the community to get help sort out my problems, help others with theirs and be a part of a great tribute to great car! And of course watch out a bunch of stunning E21!

Well... I have been trying to get the hold of the configuration of the vacuum system in the non Swedish 323i's for a wile now. The thing with the Swedish engine setup is that because of the harder pollution rules (with Australia) they installed an emission return system in the exhaust manifold controlled by vacuum contacts, thermo switches, rpm-relay etc.
For those of you don't know how it works:
The system activates when you put in 4th gear with a cool engine and return exhausts to the air intake to reduce emissions. The system is not activated that long but I can't se the benefits of this system so I want the crap gone. So thats why I turned to this forum, where I think I'll get some answers.
How does the vacuum system configured in a "conventional" 323i? This is how the system looks like in mine:


http://www.realoem.com/bmw/showparts.do ... 45&lang=en

http://www.realoem.com/bmw/showparts.do ... 50&lang=en

1. Three vacuum contacts
2. Bunch of colored vacuum hoses, connected to air intake, thermostat house, distributor and exhaust manifold.
3. Exhaust returning hoses.
4. EGR-valve between air intake and manifold.


I also wonder if there is a fault in this system could cause a jerky and irregular engine. This occurs more distinctly with a warm engine and especially in third gear (a bit in second) between about 1200 rpm till 2500 rpm. And sometimes with engine warm the idle is quite low making the whole car shake.
This could also be the cause of something else, like; poor compression; worn valves; leaking cold start valve.
Could it be a cause of something else as well?

The rear silencers are basically not in use because of a pretty big leak in the pipes, which makes it quite noisy, but it backfires much which is another problem.
What might cause this, weak fuel mixture or could this been the cause of the other potential problems?

Hehe, that's probably all, for now... =)

Thanks in advance

Welcome here!

No experience with these EGR setups but let's give it a try. There could definitely be a relationship as with a messy complex setup it is easy to have a vacuum problem that will directly influence intake vacuum thus influencing ignition timing and K-Jet adjustments. So I'd suggest to look up the non EGR setup in realoem and try to move that direction, completely. Delete all the vacuum EGR controls that are added and get back to basics. We might be able to supply some detailed info and pics of our engine bays.

Thanks!

Thats my plan, and it would be great to have a picture of a non-EGR engine to work from, connecting demanded hoses correctly etc...
It says in the manual book that this set up makes the engine run quietly and smooth, but I suppose you guys don't have a problem living without it??

Cheers!

No I'd kill it. It adds complexity on a mechanical fuel injection and ignition advance system that's 30 years old. Can't do much good I think.

Cleans up the engine bay quite a bit as well. Moving cars around here for a couple of days but I should be able to supply some detailed shots within days. Just let me know what the issues or question marks are!

^It's looks pretty clean in you engine bay, I'd say

I removed the vacuum system the other day and the problem is solved. No irrational or jerky behavior from the engine.
I think I connected the hoses from the distributor correctly - one hose enters the intake before the throttle and one after(?).

The exhaust manifold and air intake I'll just plug the coupling to the EGR-system for now. Will try to get hold of a exhaust header in future.
Does an exhaust header to an e30 m20 fit the m20 cylinder head in the e21?

Cheers!

Good news! Believe the E30 headers don't work, heard the chassis may be in the way but since that's right at the end that might be solved with some creative welding