Date: Sat, 12 Jan 2002 14:04:40 -0600
Reply-To: John Clavin <jc@AUSTIN.RR.COM>
Sender: Vanagon Mailing List <vanagon@gerry.vanagon.com>
From: John Clavin <jc@AUSTIN.RR.COM>
Subject: Re: Idle stabilizer
In-Reply-To: <5.1.0.14.2.20020112133400.0306b248@pop1.attglobal.net>
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At 01:54 PM 1/12/02 -0500, David Beierl wrote:
>>The reason for this would be to provide some signal
>>conditioning that evens out the timing between individual, erratic pulses
>>from the sender. It also would provide some wave form shaping of the pulses
>>so as to make them more uniform, and hence more reliable, as seen by the
>>Hall Control unit. The net effect would be to take a jittery stream of
>>poorly shaped pulses and replace it with a more uniform stream of evenly
>>shaped and spaced pulses.
>
>Don't think so. The sender pulses are not erratic -- this is a purely
>electronic circuit (the Hall generator). It may do some wave shaping, but
>that 's incidental to its true function which is to...wait for
>it...stabilize the idle speed, which it does by adjusting signal phase
>(timing) on the fly.
Dave - Thanks for the elaborations, but I'm not sure what you are saying if
you mean something different here. What do you mean by "adjusting the
signal phase (timing) on the fly"? That can only be by adjusting either the
pulse width itself or the timing of individual pulses relative to the
triggering incoming pulse. What is the purpose of adjusting the phase of
the outgoing pulses if not to produce a more uniform pulse train. Or am I
missing the point? What is the signal phase of the outgoing pulses being
referenced to? Please explain.
>>Disconnecting the idle stabilizer by connecting the cables to it together
>>merely sends the raw sender signal to the Hall Control unit. If the
>>electrical signal from the sender is "clean" because the sender produces a
>>good signal and the engine is running smoothly, then it is likely that you
>>can run without the stabilizer.
>
>You can run fine without it. However, you lose its benefit, which AFAIK
>is primarily to provide good torque at idle speed.
Providing torque seems to me to be a secondary benefit. Isn't he primary
purpose to provide for better ignition timing control which results in a
smoother running engine, hence more torque? Are you suggesting that even if
the engine runs well without it at idle, that disconnecting the IS still
reduces the torque available to accelerate from a dead stop?
>>If the above analysis is correct, then the idle stabilizer is always "on"
>>and performing its function when plugged in. I could see no way that the
>>ECU or Hall Control Unit could tell it to turn off for a warm engine. I
>>suspect that it may seem to turn off because its effects under those
>>running conditions are not as critical or noticeable in terms of engine
>>performance.
>
>No, it's always on -- however it only exercises control over the timing
>within a narrow rpm band. Within that band it exerts a powerful effect at
>all times. To see it at work, set up a timing light and watch the timing
>bounce around at idle. Remove it (idle stab) and look again -- timing
>will be rock-steady.
Interesting. I had not about how it might be limited to control only over
an rpm band. Certainly the observable effect is as you described, but do we
know if the circuitry is actually designed for a specific rpm band or
whether its effects are just more observable at the lower rpms? Regardless,
it is still active, "on" circuitry at all rpm's and therefore subject to
causing problems at all rpms when it begins to fail, which is really the
point I wanted to make.
Regards,
John Clavin
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