Poor Idle After Fmic Install??? Anyone Else

Discussion in '2.3L (N/A & Turbo) Tech' started by matice00, Jun 28, 2013.


  1. matice00

    matice00 New Member

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    Ok so I fabed up a front mount for my 68 with a 88 tc motor. After the install it will sometimes sputter and want to die when you come to a stop, if you give it a little gas it picks back up and is smooth running at any rpm above 1000. It did not do this before at all with the top mount. I hooked up my trusty boost leak tester and there are no leeks and holds solid 15lbs while driving, on a side note after its been running a while and nice and warm it does not do it. My ? Is do you need to re adjust the tps or anything after installing a front mount. Its a stock motor stock ecu. Thanks for any help you can give me. 20130629_183035.jpg 20130629_183035.jpg 20130629_183016.jpg
     
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  2. 4cammer72

    4cammer72 Likes to drop it and leave it crusty lookin

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    its the blowoff valve, you need to run it as a recirculation valve,,,, meaning it needs to be plumbed back into the system between the vam and turbo.... whats happening is you are releasing metered air and its going rich .. if you route it back into the system this will go away... car looks great by the way......
     
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  3. matice00

    matice00 New Member

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    Thanks 4cammer, that actually crossed my mind I'm going to give that a try and see what it does.
     
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  4. matice00

    matice00 New Member

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    Alright I had to leave town so it took me a while to test the blow off valve and recir it. It did not help, i removed it all together and still no change. Im at a loss I cleaned out the iac valve one more time, checked volts at tps all seem just fine. Any other things I should look at. Its really bugging me it ran perfect that morning driving to my shop, I swaped intercoolers put it back together and it had a bad idle right away...
     
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  5. tealtiger93

    tealtiger93 Member

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    Have you tried turboford.org?
     
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  6. fess40

    fess40 Founding Member

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    Please post any solution you find. I'm having similar issues with my '89 with an '88 swap.

    Sent from my DROID RAZR using Tapatalk 2
     
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  7. madspeed

    madspeed Colonel Mustard Mod Dude Founding Member

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    excuse my ignorance on this drivetrain, but it it mass air or speed density?
     
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  8. Red_LX

    Red_LX I’m not much help unless you’re looking for porn! Mod Dude Founding Member

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    It's Vane Air Meter (VAM) which is sort of like mass air, except it uses a door and spring to detect the air moving through the system.

    I ended up going with a blow-through VAM on my old Turbo Coupe to circumvent this same issue, and I STILL had occasional idle issues, but for the most part it ran pretty well like that. I think the electronics on the 2.3L turbo are just very finnicky sometimes.
     
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  9. KhanTyranitar

    KhanTyranitar Member

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    That is a common issue. Basically the longer length of the intake creates a delay between what the VAM says and the change actually taking place. So the computer sees a certain amount of air coming in, tries to modify the fuel and idle, and overshoots, by the time it measures the change, the conditions have changed again.

    The initial solution is to increase the base idle speed. Long term, if you can upgrade from the stock computer to speed density (PIMP, Megasquirt) or can do a MAF swap (Lighting MAF and Quarterhorse) the issue can be overcome and corrected.

    Myself I would not have opted for a FMIC built from exhaust tubing. Every elbow costs flow, and increases pressure. This means your turbo works harder to produce any given amount of boost. On a N/A car in an exhaust system the effects are less noticeable, but on turbo applications, I use all mandrel bends everywhere.

    You need to enclose the filter so that it is only pulling air from outside the engine compartment. Otherwise you are taking hot air (which is less dense than cold air), compressing it, which makes it hotter, then trying to cool it, and then trying to produce maximum power with it, but the computer has no choice but to pull timing to prevent knocking. A lot of this will mess with the VAM calculations.
     
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