I think you might have more than one problem. The idle speed issue is a result of base idle settings and not the distributor advance. While distributor advance will affect idle if the idle control system is not right, a properly functioning idle control system will compensate for advance changes and return idle to 850. Perhaps your AIC valve is dirty or hanging up due to burned spots on its motor.

Or you may have a dirty throttle body that is preventing the throttle butterfly from completely closing at idle. Or your throttle position switch is faulty or poorly adjusted(located on engine side of the throttle body near the throttle control). This switch should click "just off" idle and you should see continuity between pins one and two at idle. Continuity at idle is what signals the ECU to turn on the AIC valve to regulate idle speed at 850. Additionally, if the base idle screw is turned up too far, the whole idles speed system is defeated. Check out the bb FAQ on setting base idle for more detailed info. And clean the AIC and throttle body with carb spray.

When your timing is set to +/- 16btdc, you get more off boost performance, but max boost is limited somewhat. At 16btdc, max boost should be about the beginning of red. The way to get the best of both is with a mod to the advance/retard module on the side of the distributor. If you take the module off, you will see a round stop that limits retard. By bending this stop a bit or filing about 0.5mm off the stop you will increase the spark retard under boost. However, as you gain at full boost you will loose performance on the way to full boost. The fix is to advance spark to about 20 btdc for better off boost and transition performance.

You also should check out numerous bb posts on tweaking the APC box on the driver's side fender liner ahead of the air filter snout. Tweaking the APC box and using a 3.0 FPR will allow you to boost far into red. But first fix your base idle issue.

posted by 68.37.183...

• Timing changed RPM - why?, Tino, Sat, 26 Feb 2005 11:04:48
  • Re: Timing changed RPM - why?, JohnK, Sun, 27 Feb 2005 09:14:48
  • What does engine knock sound like., Tino, Sat, 26 Feb 2005 19:59:48
    • Re: What does engine knock sound like., Chaz, Sun, 27 Feb 2005 04:02:53
      • Re: What does engine knock sound like., Tino, Sun, 27 Feb 2005 07:27:27
  • Do you understand what timeing does?, Chaz, Sat, 26 Feb 2005 13:13:13
    • A little bit, Tino, Sat, 26 Feb 2005 15:08:11
      • Re: A little bit, RayJ, Sat, 26 Feb 2005 20:37:44
        • Ray... Stand by what I say..., Chaz, Sun, 27 Feb 2005 03:19:48
          • Makes sense., Tino, Sun, 27 Feb 2005 07:44:42
            • Re: low octane, MS, Sun, 27 Feb 2005 11:38:05
              • What did you use to choke the line to the capsule? nm, Andy E, Sun, 27 Feb 2005 17:35:44
                • Any sort of restriction, a piece of tubing ..., MS, Mon, 28 Feb 2005 13:45:40
            • One advantage with the Canadian models..., Chaz, Sun, 27 Feb 2005 11:24:29
        • lol. n/m, eric 85 900t, Sun, 27 Feb 2005 00:03:38
  • Re: Timing changed RPM - why?, JohnK, Sat, 26 Feb 2005 11:40:47 <-- Viewing This Message
    • Simple but often overlooked, Tino, Sat, 26 Feb 2005 14:56:51
    • Must have disturbed something - APC, Tino, Sat, 26 Feb 2005 12:48:06

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