problem with idle control valve?

[Will98D]

1990 535iA, 129k miles. Car is slow to start, cranks 3 - 4 seconds usually. Over last 16 months/29k miles, replaced several parts that needed it and/or preventive maintenance (fuel pressure regulator, fuel check valve, crank pos sensor, rubber fuel hoses, plugs, fuel filter, main relay, fuel pump relay, adj valves, cleaned ICV and intake, cleaned connections at temp and throttle pos sensors, ran several tanks of injector cleaner, etc.). Car runs smoothly but still starts slow (maybe once every 2 - 3 months it will start immediately). Fuel pressure holds a steady 2.5 bar for >2 hours after shutdown. Makes no difference whether you try to restart right away or let it sit a long time (hours, days, same).

The ICV seems to control the idle point fine... whether I turn on-off the A/C, lights, put in gear or N, etc, it appears to adjust the idle to maintain ~800rpm.

In the BMW E34 service manual, Section 13-41/1, it says to test the ICV you turn the car off, move the valve to completely open or closed and then turn the ignition on. The valve is supposed to buzz (does) and move about to the 1/2 open position. Mine moves to the full closed position and stays there. Before I drop $100+ on this thing, has anyone else run this test, and what were the results? What are the inputs to the computer to tell it to go to open, closed or the midpoint? My concern is that the valve is actually OK but the ECU is getting some false signal when the car is off that is telling it to close the ICV.

[rich]

This may not be much help, but next time it happens check to see you have spark. You could have a bad ignition switch. It happened to me on my 84 533IA. It started as an intermitted problem. engine would crank but not fire. Just a thought. The ICV could be sticking from age. remove and spray it with carb cleaner. I had this happen also. The car kinda galloped at an idle but still ran OK. If it was only happening when cold I'd say stuck cold start valve. Good Luck