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
|