OBD2 M52 Vacuum System - Secondary Air Pump

[luckysnafu]

Just swapped a 96 M52 into my 87 325 coupe. I got the engine to start on Sunday but I have some questions about the OBD2 components.

The car does not idle and when I rev it up to around 4k is slowly comes down then stalls out. I think part of that might be related to the cluster plug, I have a 318is cluster and plug in the car right now. I'm looking through my parts for a 325i cluster plug.

I don't have OBD2 headers, so I don't have the ports to connect the secondary air pump. Can I run the car without the pump? There is a small vacuum line that connects to the pump via a valve near the front corner of the engine. What should I do with this since it is also not hooked up? I still have the pump and valve so I can hook them up if that will help, but the air pump will be sucking air from outside, not from the headers.

What other vacuum components are related to OBD2? I have a plastic cylinder with a small "nipple" sticking out each side for a rubber hose connection. It's located under the intake and I don't know what is supposed to be connected to it (can't find it on realoem).

Thanks in advance for any help.

[FredK]

Idle quality is unaffected by the cluster plug. The tach will just read incorrectly, but it sounds like you have a gross vacuum leak.

You'll want to block off all of the unnecessary vacuum ports off on the bottom of the intake manifold. There should be 2 small vacuum ports and one large one. Only one should need to go to the FPR vacuum nipple.

That plastic cylinder is a check valve for the secondary air pump system. It gets hooked up to a squarish electric check valve that connects to the air pump control valve.

http://www.realoem.com/bmw/showparts.do?model=BG13&mospid=47485&btnr=11_1539&hg=11&fg=45

[luckysnafu]

Thanks for the info Fred. I'll dig around and block off all the unnecessary vacuum ports under the intake. The car isn't at my house so I won't be able to get to this until the weekend. I'll update then.

[luckysnafu]

Plugged up all the vacuum hoses that I'm not using and the car idles nicely now (as good as it can with open headers). Gotta install the driveshaft, diff and then get an exhaust installed and I'm all set. Thanks again for the info Fred.