View Single Post
Wayne 962 Wayne 962 is offline
Author of "101 Projects"
Wayne 962's Avatar
Originally Posted by beepbeep View Post
Reasons for ECU to close your idle motor shut might be following:

- ECU believes engine is idling too high.
- Step-motor in idle valve is faulty.
- Idle valve is wired incorrectly.

If you let the engine run with disconnected valve and it runs with somewhat high idle RPM, ECU will try to lower that RPM by shutting the valve closed. That might be the reason that secondary valve connected to ECU (but not in the loop) is getting shut by ECU. I would recomend swaping the valve and checking if idle stabilizes.
Swapped the valve out with four different ones - they all behave the same way. The engine thinks the engine speed is too high, which makes me think the rpm sensor is faulty. I have dug out my oscilliscope, and I will test it tomorrow. I have also ordered a new one, but I have no idea how to get it installed in this car. I guess I will find out tomorrow - I will probably have to put it on the lift.

Wayne R. Dempsey, Founder, Pelican Parts Inc., and Author of:
101 Projects for Your BMW 3-Series 101 Projects for Your Porsche 911 How to Rebuild & Modify Porsche 911 Engines 101 Projects for Your Porsche Boxster & Cayman 101 Projects for Your Porsche 996 / 997 SPEED READ: Porsche 911 (October 2018)

Check out our new site: Dempsey Motorsports
Old 11-28-2007, 02:49 AM
  Pelican Parts Catalog | Tech Articles | Promos & Specials    Reply With Quote #3 (permalink)