CA : Failed Smog
10-18-12, 05:43 PM
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CA : Failed Smog
Today I took my 92 SC300 5 speed to get it smogged and it failed badly. I need some help on what to fix. The smog technician said to check up on the EGR system, so I will take it apart and clean it out. But what are some other things that i can do to help lower the emissions to pass? Here's a pic of the results. Please let me know what I can do.
10-18-12, 07:10 PM
#2
I had similar number when i failed on my 94 sc3. (a month ago, just passed smog)
Things i did to pass:
-retard timing by 2 deg.
-clean the whole EGR system. The back pipe is very hard to get to it will take you a while. my nox was over 2000. i had gross polluter on both 15 and 25.
-2oz actone in 10gal gas.
-smog tech heated up cat.
Things i did to pass:
-retard timing by 2 deg.
-clean the whole EGR system. The back pipe is very hard to get to it will take you a while. my nox was over 2000. i had gross polluter on both 15 and 25.
-2oz actone in 10gal gas.
-smog tech heated up cat.
10-18-12, 07:50 PM
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I just had the timing adjusted due to it being way off. I put a bottle of Heet in before I went in to smog, I don't know if that has anything to do with it though.
10-25-12, 05:09 PM
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I still need help guys. I cleaned the EGR valve and went back in for a test but it still failed. The NOx is just too high. So the smog tech tested the vac to the EGR and it turns out that it wasn't getting vac. I traced the line back to the throttle body and it was the R port. So I cleaned out the throttle body real good and it's still not getting the right amount of vac. What could be the problem?? I need to get this car to pass smog so I can register it! I also noticed that the VSV for the EGR was broken. The nipple broke off, so I went to my local junk yard and got one off a SC400. They didn't have any SC300's so i took one off the sc400. The one on the 400 looks slightly different but it has the same plug so it should work right? The EGR is functional, it's just not getting the right amount of vac it needs.
10-25-12, 06:47 PM
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^ No I didn't clean that part because I couldn't get it off. The EGR is functional.. its just not getting any vacuum from the ports on the throttle body. The car runs fine. No idle issues or anything like that. And If I unplug any of the vacuum lines it doesn't have any effect on the idle.
Last edited by Tkhang; 10-25-12 at 06:52 PM.
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10-27-12, 03:21 PM
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10-27-12, 07:08 PM
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i had the same problem with my 92 SC400. I tried all the quick fixes ( acetone in gas guaranteed to pass ect) none of it helped. i put vac on the egr and it stumbled turned out to be the the egr vacuum modulator valve got it from Lexus now all is good. Hope it helps you
10-29-12, 04:06 PM
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Alright, I'll give that one a try. I'm still confused about why the TB isnt giving off any vacuum..? Or is it just like that? I've read that sometimes they only give vacuum at certain rpms and/or temperatures?
10-30-12, 10:11 AM
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egr is not active all the time, the lettered ports on the throttle body are ported in such a way that it only gives vac under certain engine conditions like cruise etc, just make sure its not plugged it will give the right vac.
your numbers are pretty high, I would think EGR may not going to get you there alone but then again its mostly your no numbers.
seems like they already checked your ignition timing.
how many miles do you have on your cat, and is it the original?
your numbers are pretty high, I would think EGR may not going to get you there alone but then again its mostly your no numbers.
seems like they already checked your ignition timing.
how many miles do you have on your cat, and is it the original?
Last edited by Ali SC3; 10-30-12 at 10:15 AM.
10-30-12, 03:40 PM
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The cat has 177K on it. I'm pretty sure its the original. The weird thing is that the previous owner smogged it 3 months before and it passed the NO. He failed the timing so they wouldnt let him pass smog. I think he had the engine swapped due to the other engine having a bad head gasket. So I go in and smog the car with this new engine and I found out it fails. I'm sure the cat is good. Something else is causing the high NO. My car isnt throwing any CEL's but then again I haven't really drove it alot because the car isnt registered under my name yet so I cant get it insured.