Posted by Carlie Bentley on January 08, 2002 at 11:27:26:
In Reply to: !!!!78 530i NEEDS HELP!!!! posted by Brent on January 08, 2002 at 07:45:05:
Hey Brent,
I would start first by checking all the vacuum ports. Make sure you've plugged them all and aren't having a vacuum leak pproblem. Don't worry with where they go for starters. Let's get it starting and idling right.
Unhook and plug any hoses you have running to the distributor. For starting purposes it shouldn't do any thing right now. There should only be one hose going there.
Then you need to be sure the bellows running from the Air Flow meter to the Throttle body is solid and has no cracks. If you're certain all the hoses are simply plugged and there are no open vacuum ports left the car should start and idle. Then you need to refer to the throttle body adjustment FAQ the Technical FAQ section. Make sure that's done.
Then reconnect your Vacuum retard hose to the distributor. Make sure it's connected to a port that looses vacuum pull when the throttle is opened. This port if you could see a cross section would be behind the throttle plate. Meaning at idle the port should have vacuum, but off idle the vacuum should decrease.
I'll have to double check where my fuel pressure regulator vacuum hose connects to, but If I'm not mistaken it works similar to the Vacuum retard on a much smaller scale. I believe it hooks directly onto the Intake plenum but I'll have to check.
The next most likely place for vacuum leaks on the 530i with AC is the AC Idle control valve. It's the thing that gets in the way of the oil filler cap. Make sure all those hoses are not cracked. It can cause a pretty serious vacuum leak.
Now at this point I think we're down to timing, which sounds like the problem you're having. I beat my head against the wall trying to time this thing like a chevy. It can't be done. The idle must first be set to (those in the know correct me if I'm wrong) between 1700 RPM and 2000 rpm. I think there are a couple of different schools of thought on this but some where in that range will get pretty close. You then need a timing light. Remove and plug the vacuum retard hose at the distributor end. WIth the car idling in the 1700 to 2000 rpm range aim the timing light through the small hole at the back of the engine where the engine and transmission meet. You should see a small pointer. On the flywheel there is a small tab inserted, it looks kinda like a BB when it's flying by. Get that to remain stable at the point and then, reconnect the vacuum retard hose and drop the idle back to standard. You should notice a big difference.
It sounds like you may have the vacuum retard hose hooked to the vacuum advance port which does exactly the opposite. This would cause a similar problem to what you describe as well. I would check there first.
Hope this helps
Carlie