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FAILED Emissions.. HC and NOX.. any suggestions ?

Discussion in 'General Tech and Maintenance' started by fuegie, Aug 26, 2006.

  1. fuegie

    fuegie Jdm h22a Cb7

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    Hey there.. As you can see from my title, i have failed my emissions... 3 TIMES !! :( .. Anyways, ill get to the point.
    I have a 93 Honda Accord LX with a JDM H22A auto swap. Aftermarket parts that i have is intake & exhaust,(Running JDM header/downpipe). Also being somewhat tuned by V-afc.

    Anyways, as i was saying.. after i did the complete motor swap, i took it to emissions. It failed of course, and it failed on all 3 tests: HC, CO, and NOX. HC limit was at 2.000 while i was running roughly at 4.100 and CO limit was 1.5 while i was at about 2.000. NOX limit was 1.000 and i was at 1.200.

    After i have leaned out my fuel from the v-afc for the 1000-3000 rpms, i took it back to emissions and still failed. HC and CO dropped while Nox went up.

    Now on my last try of emissions before i have to start paying for each addition runs, i leaned out my fuel even more and failed HC(but my reading went down), passed CO, but Nox went up even higher now !

    Im completely outta answers. My brother-in-law told me that the more i lean out my fuel, the more the Nox will go up because the exhaust gets alot hotter. But the more i lean it out the more HC will drop and it will eventually pass. But my Nox will still fail because its too lean. Does anybody out there know any tricks that i can do that get this thing to pass the smog test?
    So im stomped as of now. Only way to make nox pass is to tune for richer on fuel, but HC will go up. And if i lean out fuel for HC to drop, Nox will rise. If anybody can help me out here, i'd appreciate it. Oh, and just in case if you are wondering where im taking the smog test from, Im from Milwaukee, WI...
     
  2. jlicrx

    jlicrx Senior Member

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    your brother-in-law is correct - high NOx is caused by high combustion chamber temperatures - leaning the car out will cause combustion temperatures to rise - get it lean enough and the temperature will rise enough to cause detonation - do you have EGR valve on the H22? - the EGR valve is there because without it, the combustion chamber temperatures get to high - the EGR valve diverts a small portion of the exhaust gases back into the combustion chamber to help reduce the combustion temperatures - the VAFC isn't helping you out either - you may think you are leaning it out, but the ECU will read the O2 sensor and eventually adjust the fuel mixture to where it needs to be - you try to lean it out and it works for a short amount of time, but eventually the ECU will correct it - same thing if you try to richen it up with VAFC - ECU is going to sense rich condition and try to correct it - you keep adding fuel with the VAFC and eventually the ECU is not going to be able to correct for it, and you have a check engine light because the ECU thinks the O2 sensor isn't working - the VAFC is not good for trying to control fuel - it also is not that good for controlling VTEC - here is a quote from another board regarding VAFC and VTEC control:

    3: VTEC engagement point calibration.
    VTEC is a combination of 3 different things. 1: The changeover of the cam lobes. 2: The changeover of the fuel MAP. 3: The changeover of the Timing MAP. If these 3 things don't happen all at the same time, what happens?? Simple, you have a "hole" in the fuel and timing MAPS. If VTEC engages at 3000 RPMS, and the fuel and timing table follow the ECU's instructions and changeover at 5200, then have you added any more fuel and or timing from 3000 until 5200?? No. Therefore, what did you gain?? Nothing. So what, the cam changed over, but you didn't add any fuel to it, or change the timing curve. You got more air, but the ECU didn't know that it was going to get it! So it didn't DO ANYTHING ABOUT IT. Yes, adding more air makes it FEEL like you're making more power sooner, but all you're REALY doing is running lean for a few seconds.
     
    Last edited: Aug 27, 2006
  3. fuegie

    fuegie Jdm h22a Cb7

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    well, thanks for the reply.. im completely outta ideas then if that was the case (v-afc not really being able to control fuel since ecu will retune it). You may be right though, because eventually after a while the car starts to run too lean/rich and then it starts to bog down while accelerating. I have thought of another idea where i can try and do, but not sure if it will help or not. My 2 1/2" cat-back exhaust is a straight through exhaust, and i was thinking of maybe putting the stock axle-back muffler on there to help on emissions. Im not quite sure how much it will help, but im pretty sure it will bring my nox and the hc down. If i cant get this thing to pass emissions, then i guess worst case scenario will be just to sell the car. =( .. oh wells, we'll see what happends. If anybody has any other suggestions or advice, please send them my way !! thanks..

    Oh, and to your question about the EGR valve on the H22.. Yes, i do have the EGR valve and the solenoid on there. At first i was using the JDM one and then the check engine light came on after a while for the EGR, so we switched it out with my brother-in-laws H22a4 motor since he blew his motor, and it killed the check engine light, but only for a while. It will eventually keep coming back on and i asked my bro-in-law about it and he said that if im running too lean/rich then it can also trigger the check engine light to turn on for the egr because cant compensate enough for it or something. So maybe my other egr was still working but im just running too lean/rich to trigger it.
     
    Last edited: Aug 27, 2006
  4. vic42

    vic42 Junior Member

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    First in order to pass smog you should get everything back to stock, even with a cold air intake your engine will most often fail.

    Second run a few onces of acetone in the tank, the formula is 2-3 oz's for ten gallons of gas, run 2 tanks though using this formula and then on the day of the test add 3 oz's of 100% pure acetone to the tank and them fill up, in that order. Take the car for a drive and get it nice and hot and then go have it smogged.

    Don't use "Nail polish remover acetone" You must use the 100% pure stuff, you can buy it at a parts store or hardware store, its will say "100% Acetone" on the label. The more actetone the better the emmisons but the worse the fuel mileage.

    I brough my 91 civic though yesterday and i got amazing numbers, less than half the allowable numbers for NOX and HC and the CO level was at 0.5. Off course i removed the cold air intake and put the stock setup back on and removed the fart can and put the stock muffler back on. Thank God for muffler clamps!!

    A few years ago i thought this was a bunch of crap but i've been using actetone every year since and it works in all my older vehilces.

    This car has almost 254,000 Kms on it, or 155,000 miles. The only things i've replaced were spark plugs, wires and cleaned out the throttle body and off course the stock items i mentioned above.

    I'll send you the test results if you have doubts.

    Cheers
    Vic.
     
    Last edited: Aug 29, 2006
  5. eg6sir

    eg6sir Supa Mod Moderator VIP

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    how old is the cat and the O2 sensor.. i kept failing and it ended up being the O2
     
  6. reckedracing

    reckedracing TTIWWOP VIP

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    1. are you running any check engine lights?

    2. why aren't you running the stock H22 ecu?
     
  7. fuegie

    fuegie Jdm h22a Cb7

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    well.. here is an update... i've still failed emissions.. 4th time now. I finally decided to take it into an emissions reconized auto shop to give to test the car to see what the problem is. He told me that im am dumping way too much fuel. Well, that was as far as we got today, but he will give me a call when he finds out what the problem is.

    Anyways.. to answer your question.. i have a new o2 sensor from bosche, and a 1 1/2 year old cat for an accord. The cat was bought from an auto store, not sure if it was napa or what. And i am running the h22 ecu. Im currently running the Accord TCM instead of the prelude TCM because the accord tcm shifts better during gears(only using accord tcm for emissions). Just didnt want the car revving too much because the h22 tcm holds onto gears longer and if it is holding onto gears too long it probably will run rich. Oh, and thanks for the "Acetone" idea. I will have to probably give it a shot if it comes to worst case scenario. I'll have to wait and see what the mechanic says about dumping too much fuel, and whats causing it. Thanks again for all the replies. Please keep it coming if you have anything to add on.
     
  8. fuegie

    fuegie Jdm h22a Cb7

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    My Check Engine light does come on.. but that is only because im running too lean/rich and it is triggering the egr to go off. If i am running on normal, then it runs fine. I have to lean out my fuel because im running too rich and it is probably causing the check engine light to pop up. And i am running the h22 ecu. What im not using is the h22 tcm. I am currently running the accord tcm because it seems to shift better and the gearing is not holding on too long like the h22 tcm is.
     
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