PCM Diagnostics & Tuning HP Tuners | Holley | Diablo

Timing bouncing at idle, why?

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Old Jun 6, 2005 | 06:35 PM
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Default Timing bouncing at idle, why?

I have a cam (specs in sig) and just wanted to know if this was normal. At idle when sitting (no moving) the timing advance is bouncing about as high as 3degrees. But whats wierd is lets say if Im coming to a stop and I got the clutch pressed, it idles at 900 or so like its suppoed to but the idle is solid at 22*.
This is an example. Beginning half you can see my coasting to a stop and then the timing at idle starts bouncing around and has more peaks/valleys than the rocky mountains.


Ive checked all the timing tables and everything at that cell and around that cell is all the same degrees, so I dont understand where its getting it from.

Is this normal?

Dixit
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Old Jun 6, 2005 | 08:22 PM
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Its the idle overspeed and underspeed tables and the computer uses them to keep the car at its target idle
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Old Jun 6, 2005 | 10:56 PM
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So would you say this is normal or not normal.

Dixit
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Old Jun 6, 2005 | 10:59 PM
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normal unless the car is surging and hunting really bad. Is the idle steady????
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Old Jun 6, 2005 | 11:10 PM
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The idle is fairly steady, it basically sits right at 900 as I programmed it to. No hunting or anything.

Dixit
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Old Jun 6, 2005 | 11:27 PM
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Its all good. The spark variation is the Adaptive Idle doing its thing. Its tuned pretty well for less than 3* variation with a cam.
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