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Fw: '95 Jeep "EGR"

To: "Shop-Talk" <shop-talk@autox.team.net>
Subject: Fw: '95 Jeep "EGR"
From: "Bob Spidell" <bspidell@comcast.net>
Date: Tue, 27 Sep 2005 18:26:26 -0700
 re:
 
> I'm pretty sure the reason he can't see an EGR is that one doesn't exist.
 
 
 THAT'S what I was wondering about.  My Chilton's says this engine has an EGR,
 but here's what I'm beginning to suspect:
 
 Earlier models of this engine have an EGR system.  Later models have a three
 stage cat-con, and engineers were able to tweak the electronic controls enough
 to get below the NOX limits without the EGR.  Of course, this reduced the BOM
 for the car--making the beancounters very happy--but unfortunately the NOX 
level
 is borderline (probably came off the assembly line this way).
 
 The engine runs fine otherwise and, yes, I have a new and properly functioning
 O2 sensor.  Timing is not adjustable, so it doesn't look like there's anything 
I can
 do to get the NOX level down :(
 
 Thanks for the feedback.
 
 
 bs
 ***************************************************************
 Bob Spidell         San Jose, CA        bspidell@comcast.net
 '67 Austin-Healey 3000             '56 Austin-Healey 100M
 ***************************************************************
 
> Subject: Re: '95 Jeep "EGR"
> 
> 
>> 
>> On 9/27/05, CHRIS KOTTING <ckotting@wideopenwest.com> wrote:
>>>
>>> Some things to think about:
>>> Nitrogen oxidizes at very high temperatures, so there may be "hot spots" in
>>> the combustion chamber (carbon build-up?), or the old cat-con was
>>> overheating.  (The EGR valve is a good guess, since the purpose of EGR is to
>>> control temperatures in the combustion chamber.)
>>>
>>> Try a different fuel.  Some fuels contain more nitrogen.  There's already
>>> plenty in the air, but more nitrogen in the fuel will mean more nitrogen in
>>> the combustion chamber, and more NOx in the exhaust.
>>>
>>> As for why you can't see the EGR valve, it may be incorporated into the
>>> exhaust and intake manifolds in such a away as one or both has to be removed
>>> to see it.
>> 
>> I'm pretty sure the reason he can't see an EGR is that one doesn't exist.
>> 
>> --
>> David Scheidt






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