Short version of my (long/somewhat rambling) question below: a) Does anyone have recommendations for a professional rebuilder of Keihin carbs? and, b) Should a 1987 California CRX HF have an air tube on the catalytic converter?
Long version, if you're bored: I have a 1987 CRX HF, California model, that despite being in absolutely cherry condition overall, will not pass smog--hydrocarbons are too high (max allowable at 15 mph is 103 PPM--and my car's exhaust is measuring 135). There seems to be a random misfire, particularly noticeable at idle, and though I haven't yet been able to determine its cause, I am leaning towards a lean misfire condition at this point.
The engine has good compression (210 PSI +/- <5 on all cylinders), pulls a strong vacuum (21" at idle), and has just over 160,000 miles on it. The EGR valve is good, both fuel filters have been replaced, and all major ignition components test to spec. Everything about the vehicle is stock--at least to the best of my knowledge. Additionally, the car runs well at all speeds, save for a rough idle.
Does it sound reasonable to suspect the carburetor at this point?
That said, I cannot find anyone who specializes in rebuilding the carburetors for this vehicle, and am dubious that a "Carbs R' Us" type place would do an adequate job with what sounds like a very difficult carb to rebuild. I have rebuilt carburetors myself before, but everything I've read about the Keihin has scared me away from even attempting it (if anyone has any recommendations for a professional rebuilder, please let me know).
So, at this point, I am strongly considering replacing the catalytic converter. I know I should address the misfire first, but the registration is up at the end of the month, and if a new cat might be sufficient to get the vehicle to eek by the sniffer test, I'd be satisfied--especially since I've spent far too many weekends trying to track down the source of this elusive misfire.
But there's a problem with that, too--the only available California "certified" catalytic converter for this vehicle has an air tube attached to it--and this car, as best I can determine, has no provisions for that. I called the manufacturer of the converter, Magnaflow, and talked to their technical staff about this. They told me that's the only version of that particular converter they sell, and that the certification process for a "California Legal" direct fit catalytic converter is sufficiently costly that it isn't worth it for them to create several permutations of a converter for every different possible application.
When asked whether they thought blocking off or welding the air tube shut would be an option, they assured me that no reputable exhaust shop would risk losing their license to do something like that, because it would be illegal, and even if I were to have it done, I'd fail smog when the tech noticed the modification--and possibly even find myself in legal hot water for modifying an emissions control device.
Does anyone have any insight into this? In searching online, it seems that some CRX's of this vintage do indeed have provisions to feed this little air tube on the cat, and in fact many I've looked at have several additional emissions control devices/black boxes under the hood that my vehicle does not have. Being a California car, I would think that this vehicle would be armed to the teeth with every emissions control device of the time, but it appears that the CA versions of the CRX HF are lacking several emissions features found on Federal cars, including an O2 sensor.
In fact, the California HF's were EPA rated at 15% less fuel economy than the federal cars (presumably due to the lack of the 02 sensor..? According to fueleconomy.gov, none of the CA models had feedback carbs). That said, I cannot seem to verify whether the air tube to the cat is one of the features omitted in CA cars, or if my vehicle was modified at some point by a previous owner (although it has never failed the visual smog test--assuming the techs know what they're looking for).
Does anyone here have a California CRX HF, and if so, does it have an air tube on the stock cat, and the necessary provisions to feed it? Likewise, I am open to any suggestions, beyond the advice I got from Magnaflow's technical staff to plead my case to a California State Smog "Referee" in Sacramento (which is probably the only 100% legal route)?
I'd hate to think this vehicle is simply obsolete for the above reasons, especially since it runs so well and gets such amazing gas mileage.
On another note, my neighbor brags that his '04 Hummer has never failed a smog test. I'm sure the state's air quality is much better off with his 8 mpg tank terrorizing the roads than my 45 mpg CRX. Sigh…
Any and all ideas or suggestions are welcome.
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Also:
Link to the direct-fit CA approved converter for this car:
http://www.magnaflow...directfit=36967
(if the link fails to show up, the p/n is 36967)