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Old 01-11-2009, 12:06 PM   #1
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Default Setting up MegaSquirt to pass emissions

Ok, so the Miata is my summer car and it's been up on jackstands during the winter while I get MegaSquirt sorted out and my turbo installed-well, my tag is up for renewal and I have to take it in to get inspected. My stock O2 sensor was stripped all to hell when I finally got the damn thing out with a pipe wrench so I can't just throw the stock ECU back in with the narrowband. I have MS up and running with AEM wideband with AFM for now. I've been searching all over the internet on tips for passing just a normal emissions test where they put the wand into the exhaust-no dyno or anything. So, do I just need to make sure I'm at 14.7:1 AFR on idle (where I'll be running the test) and maybe retard the timing about 10 degrees at idle (which would bring me to about TDC or 5 degrees BTDC). My plan is to bring my laptop with me, drive over there, make the appropriate changes in MT so that I can pass, then change it afterwards. Any tips or does this sound right? just wanted to run it by you guys thanks!

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Old 01-11-2009, 01:31 PM   #2
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I've asked this question, a few times, and could never get a direct answer, I hope you get one. I have a few months before my inspection is due.
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Old 01-11-2009, 04:16 PM   #3
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This isn't really rocket science, particularly if you have the luxury of tuning the car at the test station. There's even a section of the manual which talks about the effects of making +/- adjustments to fuel and timing upon the various measured gasses: MS1 Extra Tuning Manual

Long story short: make sure you're running right around 14.7:1 in the cells that will be tested. Set gEGO so that it's off at idle RPM, and tweak that cell by hand. Let it do its thing otherwise, with 1% steps and a fairly long step-step delay, like maybe 75 to 100 ignition events. Retard the timing a bit, but don't get too carried away unless you have to.
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Old 01-11-2009, 05:58 PM   #4
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ok, thanks-I won't be able to tune at the station-there is always a huge line and they run people through there QUICK-two people in the same bay at once...I just noticed another issue that could cause me a problem: the check engine light doesn't come on during startup-do they usually look for that? seems like they would because I know that if the light is on you fail and they probably want to make sure you didn't disable the light...maybe I could rig up a switch to the light through the harness and momentarily light it up during start up to trick them? I'm standalone if you didn't guess...hmm
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Old 01-11-2009, 09:24 PM   #5
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If you are running the MS in standalone the CEL wont come on at startup. Chances are you will get by without them noticing. I know i have in the past.
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Old 01-11-2009, 10:24 PM   #6
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I'm running parallel and clipped the wire to the CEL in my boomslang so it never comes on. It wasn't a problem getting it inspected last year.
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Old 01-11-2009, 10:29 PM   #7
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PM Paul about this. He just took his gf's na NA thru inspection. He has a good timing map for the 94 that will help with emissions. His map helped my car pass with flying colors too when it was NA.
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Old 01-16-2009, 01:05 PM   #8
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I working on a theory about having the EVAP solenoid being controlled by MS, but suddenly realized that if I ran it to open when the fan mod was activated, it'd probably be enough fuel vapor to keep the idle up (for a bit but you only need a few seconds before MS recovers itself if it is having compensation problems) and the short time is all you need for the EVAP system to hit critical vacuum.
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