hi,
yes connecticut once again has an emission program and my 95 miata failed w/ high hydrocarbons, (185 vs a pass @ 167). i am wondering if this is due to the fact that the jr supercharger on the car froze an idler wheel and shortly there after the belt. i have ordered both parts and i am wondering if this is the only issue or if i should check for something else. btw: car has 97k on the clock and a resent valve job. thanks, peter
Well, if your S/C nose pulley isn't spinning - and it won't be without a belt on it - then you're not getting any boost. With no boost, you're in bypass mode all the time (assuming your bypass valve and actuator are working correctly) and should not be seeing any fuel enrichment at all. My experience is limited to the NB system which uses the JR Powercard for fuel enrichment - this system would not be running rich under these conditions.
However, I do not know the tricks used for fuel management on the older systems, which relied on manipulating sensor signals. I suppose it's possible that you could be seeing a problem if your bypass assembly isn't working correctly but that's just speculation, and I suspect that you'd be way down on power if the bypass valve wasn't in bypass mode.
So - assuming your bypass assembly is working correctly and your sensors are correctly connected, which are probably both true, you've just failed a test by being slightly over the limit. It could be a catalytic converter issue or ?
So I think you should check for something.
Dana
I would think the settings JR devised to get through CARB clearing might not work as well if the SC is not acting normally. JR is trying to trick the ECU in delivering too much HC (gas). I would replace belt and idler pulley, retest, and take it from there.
Leon
If the s/c isn't generating boost and is bypassed, I'd rather expect the fuel delivery to be about normal - regardless of the reason why the S/C is bypassed. It seems it would need to be this way for emissions approval in the first place. So, while your advice is obviously sound, I tend to believe that the original poster needs to prepare himself for the chance of replacing the O2 sensor and/or the catalytic converter.
Of course, we're just guessing from a description in a Usenet message ;-)
Dana
No. The ECU is tricked into thinking that the air that is coming through is at -40 C, hence dense, causing it to deliver more fuel than it should.
You are probably right here anyway. They both have obviously seen a lot of abuse.
Leon
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