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2G Need Help Diagnosing Idle

Posted by Wulf Grace, Jun 29, 2019

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  1. Wulf Grace

    Wulf Grace Probationary Member

    2
    0
    Joined Jun 29, 2019
    AURORA, Illinois
    Hello I am a new person to the DSM world and dont really know all that much about mechanics in general, so please excuse my poor use of words :D

    , I currently have a 95 Eclipse GST.
    This vehicle has been having a very rough idle since I got it.

    I recently replaced the Spark Plugs, right before I took the video listed below. Before hand the vehicle would idle poorly and potentially shut off after you apply some throttle. Now since the Spark Plugs were changed, the car still idles poorly and dies whilst idleing.

    The vehicle also has evolved and the noise you hear in the video is something new aswell.

    Heres the link :

    Hopefully some one can help me out :/

    Vehicle has
    87 Octane Gas but added Lucas Oil Octane Booster
    Replaced plugs from NGK bpr6es to Copper plugs from Champion (I just wanted to see if it would make a difference)
    A new MAF
     
  2. Techn0Nut1996

    Techn0Nut1996 Supporting Member

    124
    50
    Joined Jan 20, 2017
    Ames, Iowa
    Have you done a boost leak test? I found one at my throttle body that is causing a random rough idle, although mine is not as bad as in the video. Also, is the car throwing any codes? Might help you determine what steps need to be taken.
     

    724  3

    1998 Mitsubishi Eclipse GST
    fwd · manual · 2G DSM
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  3. delta448

    delta448 DSM Wiseman

    2,808
    83
    Joined Jan 13, 2006
    Clarksburg, West Virginia
    You need to check the balance shaft belt before you start the engine again.
     

    1K  5

    1998 Eagle Talon TSi AWD
    awd · manual · 2G DSM

    1K  11

    1997 Eagle Talon TSi AWD
    awd · manual · 2G DSM
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  4. Bleakley

    Bleakley Proven Member

    198
    46
    Joined Jan 29, 2017
    Pittsburgh, Pennsylvania
    Yeah, agreed on BLT. If OBD1 (not too familiar with how to pull codes on OBD1), go old school and start ruling stuff out. Compression, battery voltage, fuel pressure, mechanical timing, adjustable spark test, noid lights... I mean the list goes on. I wish I was better at diagnosing / trouble shooting but when it’s a shot in the dark. Take the most probable cause or the most likely thing wrong with the car you can think of and go from there.
    Edit —> DSMLink would probably make it easy as sh*t on you.
     

    Street Build 712  1

    1995 Eagle Talon TSi
    fwd · automatic · 2G DSM
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  5. Brembo

    Brembo Proven Member

    324
    63
    Joined Aug 17, 2014
    Clifton, New Jersey
    Hello. Thanks fo posting a video. I like the challenge. Correct me if I am wrong but on my iPad I don't see the engine spinning. I hear the sound but I can not confirm that it is spinning. That's number one. Second, any codes, check engine lights? Any recent repair and or work? To me it sounds like 2 things. It's either has a major vacuum leak which I would look into first. Or it has major fuel problem. Now I would not rap my head around fuel problem as I just pulled it out of my ass. So I would first check if their is any codes available. Second I would look into my voltages on the scanner and temps. Third I would look into mass air flow readings and fuel trims. Forth I would look into compression and vacuum possible back pressure. Somewhere along the lines you will have to find a problem but without a scanner or ecmlink it will be pretty hard. So first start with the basic and don't start changing random things. Also something to keep in mind that ignition module the pins get corroded and by moving the connector around it could change the way the car runs. By any chance when you raise the rpm does it start running better? More info would be great, like voltage when the car is running, intake air temp and coolant temp before the car gets warmed up, fuel pressure, compression test, vacuum, back pressure. Things of that nature. First start with vacuum leaks, need to verify that we are not leaking, something that fuel trims would show.
     

    Street Build 2K  3

    1990 Mitsubishi Eclipse GSX
    awd · manual · 1G DSM
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  6. Mauispyder

    Mauispyder Supporting Member

    392
    75
    Joined Jan 20, 2015
    Kula, Hawaii
    Sounds like the engine is more pumping air than having combustions. Check your major connections like MAF, check for spark and fuel. Check your timing belt. If you get this solved use premium not 87 plus octane booster, and stick to the ngk plugs, change the wires too.
     

    1K  2

    1999 Mitsubishi Eclipse Spyder GST
    fwd · manual · 2G DSM
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  7. Brembo

    Brembo Proven Member

    324
    63
    Joined Aug 17, 2014
    Clifton, New Jersey
    As far as the balance shaft belt goes I never experienced a problem with them so I can not comment on the simptoms but I would think it should not affect how the car runs at idle. Correct me if I am wrong, maybe someone could explain a little more. When my PCV valve hose busted open, my car run just like that at idle. Also corroded ignition module pins made my car run like pop too. Sortently boost leaks did not make my car run like in the video. I had a case at work with 6.0 Tahoe that half of the engine would just run crazy rich and it turned out to be a ground to the coils was bad. With that being said let's start with the basic.
     

    Street Build 2K  3

    1990 Mitsubishi Eclipse GSX
    awd · manual · 1G DSM
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  8. Wulf Grace

    Wulf Grace Probationary Member

    2
    0
    Joined Jun 29, 2019
    AURORA, Illinois
    As far as codes, there have been no codes, as well as there aren't any pending codes. :/

    I can particularly put input on the engine when I rev it, when idling at ~200-1K RPM it behaves like the video, anything more, the engine sounds and appears to run great, and has a consistent feeling.
     
    Last edited by a moderator: Jul 1, 2019
  9. pauleyman

    pauleyman DSM Wiseman

    5,111
    974
    Joined Nov 19, 2011
    oklahoma city, Oklahoma
    Please do some basic diagnostics. Check for leaks etc
    As above 87 octane isn't gonna cut it. Octane boost dosen't make it 91 or better. Dosen't work that way. However 87 isn't the cause of your idle. What your seeing shouldn't be hard to find
     

    Street Build 3K  1

    1997 Eagle Talon TSi AWD
    awd · manual · 2G DSM
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    tk106 likes this.
  10. tk106

    tk106 Supporting Member

    1,334
    256
    Joined Sep 11, 2017
    Cincinnati, Ohio
    +1 on all posts above.

    What's the history? Did you buy it that way, or problem occurred out of the blue?
     

    88  3

    2000 Jeep Cherokee Sport - Classic
    awd · automatic · Misc Vehicles

    116  4

    93 Civic 4 Door -sold-
    fwd · manual · Misc Vehicles

    Street Build 2K  6

    1992 Eagle Talon TSi AWD
    12.625 @ 111.42 · 1G DSM
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  11. Vegas smith

    Vegas smith Proven Member

    2,581
    1,179
    Joined Dec 2, 2002
    Houston, Texas
    Could be a sh**load of things causing this. bad compression, bad gas, maf going bad, bad mechanical timing.....you're going to have to become a mechanic real quick.
     

    Street Build 3K  10

    1993 Eagle Talon TSi AWD
    awd · manual · 1G DSM
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  12. Hickory-NC-2Ggsx

    Hickory-NC-2Ggsx Proven Member

    76
    15
    Joined Dec 27, 2018
    Lincolnton, North Carolina
    Are you getting spark on all 4? Sounds like its only running on 2 cylinders.
     

    Street Build 361  1

    1997 Mitsubishi Eclipse GSX
    awd · manual · 2G DSM
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  13. We're on Boost

    We're on Boost Proven Member

    889
    66
    Joined Aug 25, 2007
    Seattle area, Washington
    200 RPM is exactly what it looks like in the video. In your video it looks and sounds like the engine is trying to idle at about 200 RPM which I would think is almost impossible.
    Your video is good, it is very clear. And you can see the cam wheels and the belts running which is good.
    Could you turn the basic idle set screw (BISS) out to get an idle of about 900 RPM and shoot another video of it idling at that speed? Or 1000 RPM. Somewhere around 800 to 1000. Or if you have to do it with your foot, but then you would need the cam on a tripod I guess.
    My car, when it was stock, I always let it idle at about 900 RPM. It was just nicer.
     

    4K  18

    1990 Eagle Talon TSi AWD
    650 whp · 510 lb/ft · 1G DSM

    2K  0

    1990 Eagle Talon TSi AWD
    manual · 1G DSM
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  14. Hickory-NC-2Ggsx

    Hickory-NC-2Ggsx Proven Member

    76
    15
    Joined Dec 27, 2018
    Lincolnton, North Carolina
    I know in my experience when the rpm is that low and the engine sounds like that its missing on 2 cylinders. Its like i said above check to see if your getting spark on all 4.
     

    Street Build 361  1

    1997 Mitsubishi Eclipse GSX
    awd · manual · 2G DSM
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  15. Evolved4g63t

    Evolved4g63t Probationary Member

    4
    0
    Joined Jun 22, 2019
    Eagle, Idaho
    After watching the video. It seems like your only running on partial 4 cylinders. Have you checked your timing Marks?
    Make sure everything is tdc and see if your timing is off. If it's off more than half a tooth then it can cause a world of issues at least for me it did.
     

    74  1

    Eclipse GST
    fwd · manual · Misc Vehicles
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