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Discussion Starter #1
I am back , 92 164L

Originally failed all CA Smog tests (i.e. Gross polluter)
Replaced Ox sensor as this forum suggested ...Passed all smog tests BUT ---

"HC" PPM Max=110 My readout =178

Any ideas on next steps

Ron
 

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high hydrocarbons usually are the result of worn ignition components. Start with new spark plugs and see if that helps. Cap & rotor replacement wouldn't hurt. Check for vacuum leaks and make sure to run premium gas. Being as close as you are to passing smog, I'd try a can of "guarantee to pass" and the good ol' Italian tune-up if you know what I mean (some warmed up high rev's fwy driving)....good luck, Phil
 

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check yer oxy

sensor -- car running too rich
 

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Discussion Starter #5
Replaced the OX sesnor ...Improvement overall ....just left with this HC matter

Take care and Thank you

Ron
 

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Phil is spot on. New ignition parts including sperk plugs. and the ever so importaint italian tune up. Run it on the outskirts of town and pretend you are at a practice session at the Nurenburgring.
 

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Discussion Starter #7
Thank you or the heads -up....Looking for a long straight away as we speak ...

Take care

Ron
 

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What's your CO? High HC can be too rich (unburned extra gas) or too lean (so lean that it's misfiring). Or ignition related, or poor compression (not firing properly). Yes, look at your plugs and wires, etc., to see how they are.
Knowing what the CO and NOx are will help the diagnosis, at both speeds.
How long ago was the last test and what were its results?
Andrew
 

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Discussion Starter #9
Hi! Andrew....
CO =.5 @ 25mph max=.59 CO =.67 @ 15 Mph max=.71
NO=236 @ 25 mph max= 711 No = 461 @ 15 mph Max=772
HC=178 @ 15 mph max=110 HC= 85 @ 25mpH max=85

Wires, plugs, etc replaced in 09 ...OX sensor replaced in 2011 before the above readings were taken

Have a great day .....Ron
 

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All those numbers are relatively high for a modern car with Bosch injection and ignition. I wonder if your cat is about finished. How old is it?
Is compression OK?
Andrew
 

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You know the compression numbers, or you were told it's "OK"?
I'd suspect the cat then. Mitch at Muffler Works in Albany can set you up quickly and affordably if that's what you need, but he is on the wrong side of the bay from you.
Andrew
 

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HI! Andrew...Replaced CAT in 09 ...

I am live in East bay ....

Thank you for your idea's much appreciated

Ron
 

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Did you get it good and hot right before the test? Thermostat working and it's at full intended temperature?
Good luck, will be interested to see your results.
Andrew
 

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yes got it hot ....This time around will be same

Thank you for your interest...keep you posted

Ron
 

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Discussion Starter #18
Hi! Andrew........

Well failed Smog once again

NO
Max =772 mea= 244 passed
Max =711 mea=460 passed

CO
Max =.71 mea=.78 failed
Max=.59 meas=1.35 failed

HC
Max=110 mea=193
Max=85 mea=195


7-21-2011

NO passed last time

CO passed last time

NC

failed high speed 110 max / mea=178
passed low speed right at max figure =85


Do not have a clue as to where to look next ....


Ron
 

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I can only relate to 24V car

and with the usual YMMV statement

the BOSCH relacement O2 sensors dont work well in 24 V cars that are older. Not sure why but its been seen on 2 LS's that I worked on. For whatever reason, the OEM sensor seems to moderate both fuel mileage and emissions better than the 4 wire (and admittedly much cheaper) replacement that you need to 'splice in'. I can;t speak at all for 12 V cars as I have never had one.

High HC is "usually" associated with rich mixture. Temp sender to motronic reading "too cold" or O2 sensor reading 'too lean".

Have you absolutely confirmed timing is 'spot on' (both mech and spark)?
Dont confuse your temp sender gauge (at least on 24V car) with the coolant /engine temp sender for the motronic. on 24V car its 2 different senders! And , the senders are NOT the same! How can you get your car 'colder' while its thinking its 'hotter' (to lean out your mixture)?

Sorry about the editing-- I keep forgetting about 12 vs 24V!
 

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HI! Andrew...Replaced CAT in 09 ...

I am live in East bay ....

Thank you for your idea's much appreciated

Ron
What style of cat did you have put on? I have seen new cats fail often ESP the brand "CAT CO" cats. I had the same problem with a 164S and it was the "new" cat.
 
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