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Failed E-Test , NOx was high

B

boomer

CEG'er
Joined
Jan 26, 2009
Messages
30
Location
Thorold, Ontario, Canada
I took my 95' 2.5L in for the E-Test and it failed with a high NOx reading. Everything else was great.
Before I took it in I got a oil change, new air filter, put this stuff in the gas called "guaranteed to pass" (did what it said to do, drive a min. of 250 kms then just before the test I put fresh gas in) I took it up and down the highway, got it good and hot,,and it still failed ? I don't get it?
Any ideas :shrug:
I was told to clean out the EGR Valve or if its bad, change it. What do I use to clean it out with? carb cleaner and a toothbrush? :confused:
I don't know, could anyone give me some ideas how to get the NOx down to pass. :help:
 
High NOx is caused by defective EGR and front (or top) section of converter. On my Tempo once before, it was the converter, front ceramic "brick" was shattered by a scam muffler man who whacked on converter housing (thus shattering the brick inside) with a shop hammer and then pointed out "Hear all that noise like broken glass? You have a bad converter!" I wanted to knock his lights out. I had just passed inspection and tailpipe test like 2 weeks before. I refused his offer whereupon he claimed the burning pieces of converter would ruin the muffler I originally came in for and void the warranty. What a line of crap. Next year car failed for high NOx, I changed converter and it passed perfectly.
 
bad converter can be checked at any shop with a higher end scanner. they'll compare o2 sensor readings. if the post-cat o2 sensor readings match, or look very close to the pre-cat o2 sensors, you have a bad cat. very simple to determine
 
Black 98 CSVT said:
bad converter can be checked at any shop with a higher end scanner. they'll compare o2 sensor readings. if the post-cat o2 sensor readings match, or look very close to the pre-cat o2 sensors, you have a bad cat. very simple to determine
Click to expand...


95s do not have down stream O2 sensors.
 
Not arguing here, just thinking out loud. Not so sure O2 sensor in back would detect that, since the oxygen would be chemically locked into the NOx. Since front/top section strips those 2 apart so the oxygen can be burned, will oxygen not be detected if front section dies? Second O2 would definitely show back/bottom section that reduces HC/CO if it were bad though. Also, you can check O2 outputs by backprobing the correct wire with a digital voltmeter. Pain in the butt, but it can be done. And he's right, no second sensor on '95.
 
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