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Fast951 Fast951 is offline
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Join Date: Jan 2003
Location: Atlanta
Posts: 181
Wayne, Some of the items I would look at:
- TPS: If it's not signaling ilde to the DME, the idle algorithm will not kick in.
- Vacuum leak: The engine is getting unmetered air (AFM/MAF only). The 959 may be using a speed density/MAP system, so a vacuum leak may not affect it. However if a MAP sensor is in use, a altitude sensor might be used as well. Either MAP or altitude sensor can cause this issue.
- When cold, the DME enrich the mixture, a faulty eng temp sensor (reading rich) can cause the lean condition when cold.

- A faulty O2 sensor (sending the incorrect data to the DME - Reading a incorrect rich condition here) will cause the DME to lean the mixture. If the car has a test plug (round 5-pin plug), usually there is a procedure to set idle, where 2 pins are shorted. This disables closed loop and the idle control algorithm. If possible, run it in this mode and let us know what you find.

- A clooged injector(s) will cause a lean condition as well. However, it becomes a serious issue under boost (lean AFR).

Hope this helps, feel free to drop me a note if I can be of any help.

Old 11-26-2007, 07:34 PM
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