To high Nox

[John T. Luyster]

Thank you for replying.
The fuel used during the emission test I believe to be "indolene".  I was
given a choice of  a couple of fuels and chosse the same test fuel as
Inifinty/Nissan used to CARB thier vehicles.  I didn't have much of a choice.
The test lad uses "test fuel" anyway.  the headers are mild steel with a
ceramic coat.  This ceramic coat is really for asthetics than for heat
reduction or transfer.  The headers could be heating the engine compartment
thought the intake for this engine takes air from behind the left front
(drivers side) fog light.  Sort of a cold sir intake.  That's is where
Infinity rat holes the air temp sensor.  The EGRsystem is a back pressure type
system.

Carl Summers wrote:

> Hi John,
>         What octane fuel did you run the test with????? Run as high as
> legally possible to lower NOX outputs.   Intake air temp will drastically
> affect NOX emissions....big problem with superchargers...even with bypass
> valves......It's alot easier to pass the NOX for carb in winter or
> spring........any chance these headers are heating up the engine
> compartment more than stock???????I know it's expensive but you might want
> to put this vehicle back to stock and make sure it passes....you might be
> surprised.....hth's
> -Carl Summers
>
> mailto:intech at writeme.com
> Click on the above link to respond privately.
>
> -----Original Message-----
> From:   John T. Luyster [SMTP:jtracer at fea.net]
> Sent:   Sunday, August 01, 1999 12:44 PM
> To:     gmecm at efi332.eng.ohio-state.edu
> Subject:        To high Nox
>
> I have a 1999 Infinity QX4 that I'm trying to get a set of headers
> emission legal (Smog Exempt) in California.  My first test failed
> because of high Nox.  This is determined by a formula they come up with
> that extends the results out to at least 50K at which point my Nox
> exceeded that limit.  (It would pass a standard street smog test no
> problem)  After some investigation I found an Infinity Service Bulletin
> that suggested adding a ground wire from the intake manifold to the
> righthand cylinder head.  Further diagnostics revealved a lazy or slow
> O2 sensor at which time I replaced all four.  After this I had the
> vehicle sniffed to verify any changes.  The Nox was down substantially.
> At this time I set all the SRT's and drove approx. 50 miles to make sure
>
> no DTC's popped up.  Off to the test lab again and failed again with
> high Nox.  This vehilce has no mods done to it.  Factory ECU. The only
> thing I can think of might cause this high Nox would be the design or
> flow of the tube off the header to the EGR on the engine.  Any ideas????
>
> JT