RE: More 164S Failed CA Smog

[Charles Slayman <Charles.Slayman@domain.elided>]

	OK, I think we need our CET (Chief Emissons Technolgist) to weigh in on 
this question (Eric S - that would be you):
	If a catalytic converter is going bad, are emissions worse at low RPM or 
high RPM?  My own symplistic reasoning is that the emissions would get worse at 
high RPM because you are swamping it with more gas and it's reduced capacity 
cannot handle it.  This is the opposite of what Rich is seeing, so I tend not to 
suspect the cat con.
	On the other hand, if there is a problem that manifests itself at idle 
and is less important at high rpm, this would explain Rich's problem.  For 
example, a leaking injector or a slightly burned valve would have more of an 
impact on combustion of that cylinder at idle.  When rpms increase, the injector 
leak (or blowby of the valve) would be less signifigant.
	Also, leaning out the mixture only effects emission at idle.  At high 
rpm, the mixture setting is less signifigant according to the Alfa manual.
	Something to think about.  Hope Rich doesn't have to replace his cat.
	
Cheers,
Charlie	
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Subject: More 164S Failed CA Smog
Date: Fri, 11 Jan 2002 14:46:46 -0800
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From: "Rich Lasner" <rlasner@domain.elided>
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As I posted previously, I fixed the coolant temp sensor and cleared the
1-2-1-4 codes, only to fail the idle part of the CA smog test on my
second try. It's the opinion of the 2nd shop that the cat is shot. The
test results were:
@ 2500 rpm- car passed
HC 64 (passing is 140 or less)
CO .20 (passing is 1.00 or less)

@ idle (799 rpm)- car failed
HC 166 (passing is 120)
CO 1.77 (passing is 1.00)

Since the car passes at 2500 rpm, does anyone have an opinion about a
possible reason (other than the cat being dead) for the idle test
failure? I thought my idle mixture control device appeared to be working
last time I cleaned it and checked it (I checked the action of the door
manually, then put voltage through it at startup and watched it open and
close). Perhaps a bad O2 sensor (again?), an air leak or the coolant
sensor is actually malfunctioning (I will test it with a volt/ohm meter
over the weekend)? I cleared the 1-2-1-4 code, and the Motronic reads
4-4-4-4 again. Please let me know if you can think of anything to test,
as the cost of a cat is high, especially if it's not the problem. Thanks
for your help in advance. Did I mention the radiator sprung a leak on
the way to the smog station?!

Rich Lasner
92 164S
ARA
AROC
Mill Valley CA

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