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Guest
Anonymous Poster
Wynlover225@aol.com

Feb 19, 2007, 10:20 AM

Post #1 of 5 (1662 views)
Emissions Sign In

My 1992 Plym Acclaim w/2.5L 4 cyl failed emissions insp for NOx reading 1529 on a 970 max std. I replaced cat converter as muffler shop dtermined it to be bad. NOx went down to 1469 still failing. I do not know where to look next. Any ideas?


DanD
Veteran / Moderator
DanD profile image

Feb 20, 2007, 6:05 AM

Post #2 of 5 (1652 views)
Re: Emissions Sign In

Does this engine have and EGR (exhaust gas recalculation) valve?
Some did some didn’t in 92 and I can’t remember whether it was the 2.2 or the 2.5 that did?
Depending on whether it does or not will determine which way we go to get this thing to pass the NOX.
There are ways of sneaking a non-EGR engine through a test if all else fails.
Dan.

Canadian "EH"






Guest
Anonymous Poster

Feb 21, 2007, 8:35 PM

Post #3 of 5 (1649 views)
Re: Emissions Sign In

I think it does (have an egr valve). I was told that the numbers are much too high to be the EGR valve. Do you disagree?


DanD
Veteran / Moderator
DanD profile image

Feb 22, 2007, 6:27 AM

Post #4 of 5 (1644 views)
Re: Emissions Sign In

Do I disagree??
YES!
A properly functioning EGR system on an engine running the way it was intended will reduce NOX emissions by at least 50%! The major contributor to the production of NOX (Oxides of Nitrogen or photochemical Smog) in an internal combustion engine, is load and heat. We can’t do a lot about the load on the engine; the engine has to push the car down the road but we can do something with the heat generated during the combustion process and that’s where the EGR system comes in.
Basically the EGR introduces inert gases (exhaust) back into the combustion chamber to take up space which in turn will reduce internal combustion temperatures. In other words to help fill up the combustion chamber with something that doesn’t burn.
Yes this exhaust gas is hot but nothing compared to the heat generated by the combustion of compressed hydrocarbons and oxygen; again because there’s nothing left in the exhaust gases to burn it has a cooling effect on the over all combustion chamber.
When I say a cooling effect I don’t mean that by having an EGR system repaired you’re going to see the engine temperature gauge suddenly drop. That’s because we’re talking combustion temperatures, which the cooling system of the vehicle has been designed to look after via the thermostat.
I’m an emissions repair tech here in Ontario’s emissions testing program and I have seen so many catalytic converters condemned when yes they may be on the weak side but would still get the job done if the input gases from the engine were down to an acceptable level.
Dan

Canadian "EH"






steve01832
Veteran
steve01832 profile image

Feb 22, 2007, 7:34 PM

Post #5 of 5 (1634 views)
Re: Emissions Sign In

I have cheated on a few customers' cars by replacing the spark plugs with a colder plug. This is more applicable on cars with over 100000 miles on them.

Steve






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