Barely Passed Smog!

[3p141592654]

Smog test today. Had to pay an extra $20 to cover the new LPFET test, grrr.

I've been tracking my emissions over the years, and HC has been creeping up. Today I passed the 15mph test at 104ppm with the limit at 106ppm. A/F has been creeping down as well, and is at 14.68 today.

Original cat, O2 sensor, but passes the cross count test just fine. Any ideas? I'd hate to have to put a one pass cat in next time.

Doesn't look good for 2011.

 

[hvyman]

maybe egr getting clogged up. last time i pulled the cooler cap off my 88 the carbon was caked on. less air moving would account for the richer a/f.

just a thought good luck.

 

[jetjock]

Some are charging extra for LPFET because the state has only certified two systems and neither are cheap. Fwiw I built my own. Not nearly as automated but does the job.

Would like to see all the gases Jon, for both speeds. Otherwise it's difficult to distinguish between high HC caused by poor catalyst efficiency and high "stand alone" HC. Stand alone can be a bear to track down. Valve and/or CC deposits, PCV system, dirty oil, leaking valves, rings, fuel dilution of the oil, stuff like that. Remember, PCV is designed as an emissions system for HC because 90% of blowby occurs on the compression stroke.

Either way a new cat will clear it up but may mask the problem if it's high HC alone. What'd be optimum is a peek at the feed gas but I'm guessing you're not in possession of a NDIR analyzer. Cross counts may be OK but how's the average O2 signal at 2500 rpm? 450 mv?

Have you temp checked the cat? May well be time for a new one. You already know my opinion of the one pass junk if you're planning on keeping the car...

 

[3p141592654]

Found an error in my 2009 data, so the AFRs aren't as bad as I had plotted before.

No NDIR analyzer I can take home unfortunately. One of these days I should drop by your house, as the inlaws are in Arcadia, and I could use an excuse to get away! :biglaugh:

 

[jetjock]

What's up with the NOx? I find that hard to believe, especially with CO that low. Going off that data alone it looks pretty good. CO2 is right up there and mixture looks fine. Course, I have no idea what it'll be like in 2 years.

I'm gonna guess the oxidizing bed is tired (even though it seems to be processing CO) and you should feel OK about replacing the cat without worry of masking. It's not as if you didn't get your money out of it. Still, without sampling the feed gas under load it's an educated guess. Next time go in with a new cat, fresh oil, verified PCV, and a recent on-the-car injector/valve clean. You can buy (or build) the apparatus for that cheap. A piston soak wouldn't hurt either.

Sure, let me know if you're ever around. Can't promise I'll be but who knows. If it comes to it I could be convinced to ship you one of my smallish 4 gas NDIRs. Not the portable 5 gas though...the thing cost $4K and it's delicate. Besides, you don't appear to have much of a NOx problem

 

[3p141592654]

Thanks Gary. The week before the test I made a trip down to San Diego, 5 hours down and 3 hours up, so I figured the volatiles would have boiled out. The oil has about 2k miles on it as well. I did no special prep for this test, so hopefully your suggestions will help next time.