LT1-LT4 Modifications 1993-97 Gen II Small Block V8

failed e check. NO to high

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Old Jul 3, 2012 | 07:53 AM
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Default failed e check. NO to high

car failed e check had NO reading of 1059 legal limit is 796. two brand new cats. two new 02s. how do i fix this.


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Old Jul 3, 2012 | 11:53 AM
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Try cleaning the MAF, check for corrosion on all wires, make sure your plugs are good and gapped properly, check ohms on wires, scan for any stored codes, air filter is good, etc.
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Old Jul 3, 2012 | 05:53 PM
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make sure you have the car warmed up before you go, I failed my check about a month ago because I just drove straight there. My NO levels were something around 750. I went again a week later having changed nothing, however I took a much longer route there, and my NO levels were something around 300
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Old Jul 3, 2012 | 06:01 PM
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You need to test the EGR system to make sure it functions. http://shbox.com/1/4th_gen_EGR.html
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Old Jul 3, 2012 | 08:15 PM
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Originally Posted by flame
You need to test the EGR system to make sure it functions. http://shbox.com/1/4th_gen_EGR.html

This. A mechanic warned me that by removing my EGR valve the NOX might be too high with the sniffer. Check the valve and see if it's okay.
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Old Jul 5, 2012 | 09:21 AM
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Originally Posted by goldylocks
make sure you have the car warmed up before you go, I failed my check about a month ago because I just drove straight there. My NO levels were something around 750. I went again a week later having changed nothing, however I took a much longer route there, and my NO levels were something around 300
is there a mechanical reason why this will work for me? because i drove straight to the station 5 min from my house on cold start.



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Old Jul 5, 2012 | 09:33 AM
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Not saying that this will work, but it has for two of my friends that swear by it when they had failed emissions testing in the past. They added a bottle of RXP to two tank fulls of fuel. That was all they did and both cars passed. I think one of them only did one tank, but none the less it may be an inexpensive and easy fix.
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Old Jul 5, 2012 | 09:57 AM
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whats rxp?


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Old Jul 5, 2012 | 10:09 AM
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You know, we've been fighting this battle with my sisters 94Z for months. We've replaced everything and it still hits too high on NOx. Last resort is to run the aforementioned guaranteed to pass in a bottle stuff. I have heard more than once that it works.
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Old Jul 5, 2012 | 10:41 AM
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Originally Posted by 9D4Z28
whats rxp?


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It is a fuel additive that you can get at Pep Boys and other places. It may be snake oil and I am very cynical about these things, but this one has worked in two cases on others that are as cynical as I am.

It is about $8 per bottle. No guarantees it will work, but that is the first thing I would try if I was in your shoes. I am naturally lazy and things that work this easy are my crack.
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