Why is this 533i Idling Like Garbage

All,

My 533i is idling rough. After the car heats up, the engine revvs from about 800RPM to about 1800RPM, then cuts off. Above 2500RPM, the car revvs just fine, but the car sputters below 2000RPM, even in gear. My friends and I are completely stumped on this one. We have replaced the Throttle Position Sensor, the O2 Sensor, and cleaned the throttle body.

Here is a video to give a better idea of what I am dealing with:


Any ideas on what the issue is? Any solutions?

Thanks much!_a_

you might try disconnecting the o2 sensor. If it does not change then it is bad. Have you tried changing the spark plugs? Cap and rotor? or at least looking at them.


Andy

We have checked the spark plugs, and they are in good shape. The distributor cap is in rough shape, but appears to be functioning correctly. I have not tried disconnecting the O2 sensor; however, it is possible the connection to the sensor may be need to be replaced as it was rather rusty when I replaced the sensor itself.

Fuel filter, fuel rail pressure and 'rig' injector clean/test/pattern check.

Try a voltage check on the air flow meter. Mine was bad and putting out erratic voltages, causing a very bizarre idle problem. It went from annoying to randomly stalling while driving very quickly.

That idle problem sounds like it's caused by a bad idle control valve that's either sticking or not opening up. Does your 535 motor have something that looks like this part?

He does have the ICV, but is the older model. It could also be your idle control module, which is below your ECU in the glove box. It is green. The idle in the 533i was not controlled by the ecu but this module. When it is idling badly try fitting the box. If it helps then you know it is the module.

Andy

I have the correct idle control boxes and valves to fix that problem. 4 or 5 of each to choose from all from known working cars. In the CL post below you can see a few in the bottom right hand corner in the picture of parts on the bench. I test most parts I sell that are easy to test so i will test the control box and if I have time the idle valve.

http://seattle.craigslist.org/see/pts/3588180215.html