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Car failed emissions for high NOX: Suspect Spark Plugs?

Help, Advice and DIY Tutorials on Volvo's extremely popular car line -- Volvo's 1990s "bread and butter" cars -- powered by the ubiquitous and durable Volvo inline 5-cylinder engine.

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rmmagow
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Re: Car failed emissions for high NOX: Suspect Spark Plugs?

Post by rmmagow » Tue Feb 12, 2013 4:01 pm

I know it was mentioned the car has no EGR, but is that how it came from the factory? My understanding regarding EGR was that it is meant to drop combustion temps and that in turn dropped NOx emmissions. With your numbers so close, I would try a couple of cans of Cat cleaner and go through again.


1998 V70 AWD 228K - Daily Driver
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appropriatenoises
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Re: Car failed emissions for high NOX: Suspect Spark Plugs?

Post by appropriatenoises » Fri Feb 15, 2013 5:04 pm

As far as I can tell that's how it was manufactured. Unless someone changed out the intake manifold; there is no evidence of an EGR ever being present. I'm in agreement with your understanding of an EGR system and indeed wish my car was equipped with one. I probably wouldn't have installed the IPD system had I known.

P.S./edit: jimmy57 - thanks for your detailed explanation of the relationship between CO/HC and NOx, and the role the O2 sensor plays. I appreciate your expertise, and am grateful to be a part of this forum.


-Steve

Past:
1977 240-crushed
1981 245-on a fenceline
1987 740-on a fenceline
1998 S70 T5M- sold.
1967 P220 (Amazon) - lofty ideal, not good for a pragmatist.
Currently:
1996 855R- paid more than I wanted, sunk in more than I should! But it's worth it.

appropriatenoises
Posts: 38
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Re: Car failed emissions for high NOX: Suspect Spark Plugs?

Post by appropriatenoises » Wed May 01, 2013 9:36 pm

Sorry for the bump - but I hate when I spend 10 minutes reading a thread and then get to the end and the OP hasn't posted a resolution of any kind:

In this case, I can't give a definitive answer as to the source of my NOX woes, but I'm betting jimmy57 is right. The problem is, it's now irrelevant because I'm moving in a month to a region with no emissions testing and don't need the car to pass anymore.

My advice, be wary of aftermarket exhaust systems if you live in a state/province with emissions testing. They may sound cool and be a viable replacement option for your stock system (price wise) but odds are good that this is the source of my problem. Sorry I can't be more definitive than that.

If someone wants to send me $23 I'll take it through the inspection lane one more time for gits and shiggles, since I've done one of the things jimmy57 suggested (backed off wastegate actuator - previously set to 6psi!!!) and see if that gets a pass. But I don't really expect anyone to do that!


-Steve

Past:
1977 240-crushed
1981 245-on a fenceline
1987 740-on a fenceline
1998 S70 T5M- sold.
1967 P220 (Amazon) - lofty ideal, not good for a pragmatist.
Currently:
1996 855R- paid more than I wanted, sunk in more than I should! But it's worth it.

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