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Thread: Mixture settings using a Digitla TRUE RMS Metter.

  1. #11
    One of those purists you keep hearing about. sdg3205's Avatar
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    Quote Originally Posted by norcimo View Post
    Digital meter was too complex.

    Got my self a analog dwell meter on Amazon that has a scale for 4 -6 -8 cyl.

    I saw a video on youtube of a meter holding very steady at 21 degrees
    ... this does not seem right..

    the book says its suppose to be 38-45 ..(correct me if I'm wrong)

    My meter has a 6cly scale, and when set the mixture to exactly like the video, its does not idle well at 750RPM.

    I had to make 900 -1000...I know this is not right.

    So I went down to 750 -775, I adjust the mixture and till the needle goes up and down over 38-42 average over the 40 mark, I can idle 750 smoothly and the engine works great, no rich smell, no idle hunting.. so which one its suppose to be? steady needle at 21.5? or the alternating over 38-42.. is the video misleading?


    Thanks
    The Actron meter? Use the 8 cylinder scale and double the values. I tweak it to swing between 20 and 25 (so 40 and 50, with an average of 45).

    A steady needle means the lambda system is not running a duty cycle and you're beyond the range it can handle. This is called "open loop." When the needle swings, it is running "closed loop" which is a range within the capacity of the system, but not necessarily where it ought to be. You can be closed loop but running either too rich or lean.

    If you're mixture is now way out, start from scratch, recrack the injectors to re-establish baseline, fire up the car, let it get to OPERATING TEMPERATURE and try again on the 8 cylinder scale.

    Setting the mixture takes some practice and patience. You'll figure it out.

    Here's a video that shows both dwell and duty cycle simultaneously.
    Last edited by sdg3205; 04-17-2016 at 01:59 AM.
    Dave

    Here, somewhere.


  2. #12
    Senior Member Bitsyncmaster's Avatar
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    Setting the closed loop book value of 40 deg. requires you use the 4 cylinder scale.

    When your running closed loop (dwell reading varying) you probably have the correct fuel mixture at that moment but if the dwell is not averaging 40 deg. then your engine will not maintain the correct mixture when starting, warming up, altitude changes, etc.
    Dave M vin 03572
    http://dm-eng.weebly.com/

  3. #13
    Member norcimo's Avatar
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    Quote Originally Posted by sdg3205 View Post
    The Actron meter? Use the 8 cylinder scale and double the values. I tweak it to swing between 20 and 25 (so 40 and 50, with an average of 45).

    A steady needle means the lambda system is not running a duty cycle and you're beyond the range it can handle. This is called "open loop." When the needle swings, it is running "closed loop" which is a range within the capacity of the system, but not necessarily where it ought to be. You can be closed loop but running either too rich or lean.

    If you're mixture is now way out, start from scratch, recrack the injectors to re-establish baseline, fire up the car, let it get to OPERATING TEMPERATURE and try again on the 8 cylinder scale.

    Setting the mixture takes some practice and patience. You'll figure it out.

    Here's a video that shows both dwell and duty cycle simultaneously.
    Yes, ACtron Meter.

    Thank you.. I knew it was not perfect.. was ok, not exactly where it suppose to be. I will make video and post the results.

  4. #14
    Member norcimo's Avatar
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    Quote Originally Posted by sdg3205 View Post
    The Actron meter? Use the 8 cylinder scale and double the values. I tweak it to swing between 20 and 25 (so 40 and 50, with an average of 45).

    A steady needle means the lambda system is not running a duty cycle and you're beyond the range it can handle. This is called "open loop." When the needle swings, it is running "closed loop" which is a range within the capacity of the system, but not necessarily where it ought to be. You can be closed loop but running either too rich or lean.

    If you're mixture is now way out, start from scratch, recrack the injectors to re-establish baseline, fire up the car, let it get to OPERATING TEMPERATURE and try again on the 8 cylinder scale.

    Setting the mixture takes some practice and patience. You'll figure it out.

    Here's a video that shows both dwell and duty cycle simultaneously.
    here is 06097 dwell

    https://www.youtube.com/watch?v=61kDXnjQJSY

    Thanks

  5. #15
    Member norcimo's Avatar
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    Quote Originally Posted by norcimo View Post
    Yes, ACtron Meter.

    Thank you.. I knew it was not perfect.. was ok, not exactly where it suppose to be. I will make video and post the results.
    one last question,

    is this suppose to be done with the O2 sensor disconnected?

  6. #16
    Senior Member Bitsyncmaster's Avatar
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    Quote Originally Posted by norcimo View Post
    one last question,

    is this suppose to be done with the O2 sensor disconnected?
    You have to have the whole lambda system working to adjust mixture via dwell readings. So yes the O2 sensor has to be connected.
    Dave M vin 03572
    http://dm-eng.weebly.com/

  7. #17
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    Would someone please post a link to the dwell meter that works? I've been hunting for an analog actron meter but I haven't been able to find one... Just looking for a meter that will work well for this application. I have a fluke but there are no frills. ��

    Thanks!

    Edit
    Nevermind, I found it and bought it from eBay: http://m.ebay.com/itm/Actron-CP7605-...-/401172479360
    Last edited by spikeygg; 10-06-2016 at 08:54 PM. Reason: Found the answer!

  8. #18
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    Quote Originally Posted by spikeygg View Post
    Would someone please post a link to the dwell meter that works? I've been hunting for an analog actron meter but I haven't been able to find one... Just looking for a meter that will work well for this application. I have a fluke but there are no frills. 😔

    Thanks!
    You should try to get an old analog dwell meter with an actual meter that has a needle. Because you are trying to measure a modulating signal a digital meter won't give you proper readings since it is constantly changing. You should not have to spend much and can find one at any car show that has vendors that sell old stuff. You should not have to spend more than $10. To get a graphing digital meter will cost you a lot more.
    David Teitelbaum

  9. #19
    Administrator Ron's Avatar
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    Quote Originally Posted by spikeygg View Post
    Would someone please post a link to the dwell meter that works? I've been hunting for an analog actron meter but I haven't been able to find one... Just looking for a meter that will work well for this application. I have a fluke but there are no frills. ��

    Thanks!

    $25.00+S&H
    http://www.ebay.com/itm/Actron-CP760...1X4uDw&vxp=mtr

  10. #20
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    Quote Originally Posted by David T View Post
    You should try to get an old analog dwell meter with an actual meter that has a needle. Because you are trying to measure a modulating signal a digital meter won't give you proper readings since it is constantly changing. You should not have to spend much and can find one at any car show that has vendors that sell old stuff. You should not have to spend more than $10. To get a graphing digital meter will cost you a lot more.
    Quote Originally Posted by Ron View Post
    Ha-ha I beat both of you by just a couple of minutes... $26 shipped.

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