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1G Timing and IDLE

Posted by Adrian97, Jun 30, 2019

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  1. Adrian97

    Adrian97 Proven Member

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    Joined Mar 3, 2018
    Göteborg, Europe
    Hello i want to set timming tomorrow and I saw this post
    " Base Idle & Base Timing affect each other - IMO due to the weird ass angle we have to view the Marks from when you are squatting down & peeking thru the belts & "see" 5 BTDC you are really set at about 7 BTDC - SO when you see 2.5 BTDC it's actually about 5 IMO - I try to be in the same position/angle whenever I set mine halfway between 5 & 0 BTDC & IMO that is 5 in the real world & "seeing" 0 would be 2.5 BTDC real world IMO... BTW on my Pocketlooger I'm pulling 22 - 25 advance at WOT (Tuning guide reccommends NO LESS than 15 at WOT) & see as much as 46 degrees advance on Pocketlogger in some throttle positions - ZERO knock on 92 or 93 Octane in Winter (which of course means I could bump up Timing OR Boost) - but it runs great & I don't want to fry this old Turbo quite yet - seeing 13 PSI on POS Stock gauge. "
    here is the link: https://www.dsmtuners.com/threads/timing-adjustment.278448/ post #3
    Does it mean that i need to set my timming to 2,5 BTDC on the harmonic balancer or 5BTDC like every one? I want to be at 5 BTDC.

    And second question: When i set idle at 900 which accessories off lights,fans.... so when I turn accesories on it should fall to ex. 750, and stay or grow up to 900 ?
     
  2. pauleyman

    pauleyman DSM Wiseman

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    oklahoma city, Oklahoma
    Weird angle? I didn't think so. Also the Mark is clear under a timing light and it's designed to be very close to the scale. I've had no problems and make no "adjustments"
     

    Street Build 3K  1

    1997 Eagle Talon TSi AWD
    awd · manual · 2G DSM
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  3. Cherry

    Cherry Proven Member

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    Hull, Georgia
    From my understanding you want to do all the groundings to set the idle and set it to 750rpm. The reason you ground the 2 pins out is to put the ISC in its neutral state. After the car is shut off and the grounds removed the ISC is supposed to keep it at 750rpm give or take 50-100rpm. If you set it to 900rpm the computer will control the ISC to try to keep it around 900rpm.

    That is my understanding of it from the vfaq. It's not like an older car with a choke and you just set the idle and basically forget it but I wish it was like that. But we have electric fans that contribute to power drain as well as the ac pump and the computer is supposed to counteract those turning on by allowing more air into the engine.
     

    Street Build 256  3

    1991 Mitsubishi Eclipse N/T
    fwd · manual · 1G DSM
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  4. Adrian97

    Adrian97 Proven Member

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    Joined Mar 3, 2018
    Göteborg, Europe
    Ok , my car idles at 900 which accesories Off and 750 which accesories ON. So something is wrong.
     
  5. steve

    steve DSM Wiseman

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    St. Charles, Illinois
    Only if you have changed the programmed idle in the software, otherwise the ECU will try to lower the idle back to 750 and that may drive the ISC out of range.

    Yes, If your car idles at 900 rpm and drops under load to 750 rpm there is something wrong...
     

    3K  0

    1991 Mitsubishi Eclipse GSX
    manual · 1G DSM
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  6. Adrian97

    Adrian97 Proven Member

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    Joined Mar 3, 2018
    Göteborg, Europe
    I will try reset BISS screw i and adjust idle agian to 750, maybe someone seti it to 900 and ecu try to lower the idle back.
     
  7. Cherry

    Cherry Proven Member

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    Hull, Georgia
    Ah makes sense. I take it you would only be able to do that with an eprom ecu with link or a stand alone system?
     

    Street Build 256  3

    1991 Mitsubishi Eclipse N/T
    fwd · manual · 1G DSM
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  8. steve

    steve DSM Wiseman

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    St. Charles, Illinois
    I assume you are referring to my comment on idle speed. It's a part of the ECU programming, so you need either a EPROM ECU, one of the Mitsubishi flash based ECU's, or a third party standalone ECU to reprogram it.

    The software has a table of target idle speeds depending on coolant temp and adjusted based on various loads like the AC is on, or power steering is being used, you're coasting, If the car is an auto and in drive, etc. As I've discussed before, when the Idle position switch is closed the ECU will try to manage the engine speed using the ISC/IAC and ignition timing. The only way the engine will idle at another rpm is by disabling the inputs telling it to idle, or the devices it uses to control it, or the software that sets it.
     

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    1991 Mitsubishi Eclipse GSX
    manual · 1G DSM
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