Advice I got on helping with smog test (1 Viewer)

[e9999]

Just passed my biennal PRK smog test. Had an interesting conversation with the friendly shop boss. (What an unusual pleasure to find a place where the folks are friendly and not surly or disdainingly expressing how much of a favor they are doing you by deigning to test your car and charging you a $5 transfer fee for the electrons needed to send the results online... ).

Anyway, as usual, I got my engine good and hot beforehand and I left if running idling while waiting. Probably a good 20 mins this time.

But, the results weren't as good as 2 years ago.

That time I got 0.0 and 0.0% for CO and 1 and 1 ppm for HC. Unbelievable, no?

This time it was worse. I got 0.01 and 0.01 for CO but 12 and 20 for HC. Still easily passing but not astonishingly good.

So I asked the guy if he thought that I was right in letting the engine idle before the test cuz that was a bit long. Well, according to him, it's a mistake to just keep it going at idle and it would be better to run it for a couple of minutes at 2,500 rpm just before the sniffing. I assume to "clear up" the cats in some way.

That does seem to make sense intuitively, and in my younger days I might have thought of that myself , but I'm no expert, of course, so no idea if this is correct. But I will try that next time.

(oh, and if that makes any difference, I was running some ProGard in my tank.)

Just passing on a piece of free advice worth what you paid for it...

 

[gravygrabber]

Those are great numbers I wouldn't look for anything wrong with those. I smog a ton of cars (or used to before my recent move out of CA) and those are definitely low numbers.

Running the engine over 2500 rpm super heats the cat/s and makes them work much better. You can even burn off any junk that may have coated the substrate inside. You don't want to do it for too long however you don't want to melt the guts out of it.

 

[75CorollaGuy]

Agreed. It heats the cats up, which is how they work to burn off the exhaust. But as stated, just do it for a short time before a test, otherwise you melt the catalyst in the converters and destroy the converters/clog them up.

Glad you passed the test!

 

[e9999]

OK, but if you can't run them for more than a couple of mins at 2,500, how come they don't melt when you're high rpm crawling in low for a while with little air cooling?

 

[Romer]

For the best results, run the tank empty, fill with premium and add 1 or 2 bottles on Heat (removes water) drive for 20 minutes before you get to a station. That has helped some club rigs that had to retake the test

 

[e9999]

did another smog test, again the guy said it is a mistake to keep the engine idling immediately before the test as it will accumulate excess HC in the cats etc according to him. Better to run it at 2500 rpm for a couple of minutes he says.

Now, of course, they are idling it a fair bit during the test itself, but it may still help to clear the cats a bit before.

 

[surfpig]

That makes sense. I think they idle kind of dirty. So that could muck up the cats.

 

[e9999]

Very interesting: Here is what I found in the smog test rules posted by the California BAR:

"Inspectors shall not attempt to superheat the catalyst. Do not increase the engine RPM or load during the 3-minute idle period or during the tailpipe emissions inspection sequences except as necessary to perform the initial visible smoke snap test as described in Appendix A. Any methods used to artificially increase catalyst temperature are prohibited."

Basically, the State tells the tech you can NOT superheat the cat, I imagine because that would lower the emissions. But nothing says you can't do it yourself immediately before the test. Although they may have been smart enough to put in the 3 minute idle period precisely to lower the cat temps...

 

[Zimbwanabe]

Mine failed initially, so on the advice of a friend, I finished off the tank, put in a bottle of "guaranteed to pass" liquid, topped with premium, then did about 10 miles on the freeway with the OD off to blow it out, then took slow side streets back to the station. It passed. I didn't analyze the numbers, I just wanted to pass. Oh, and I left the battery disconnected over night. No idea which of these things did the trick, or if it was a combination of everything, but it worked.

 

[e9999]

you really do not want to disconnect the battery right before a test in California as some of the monitors will show "not ready" if you don't drive enough after reconnecting the battery, and if there is more than one, you will be automatically failed from what I read. You may have been lucky that you were down to only one Not Ready monitor.

 

[inkpot]

Check the label on the can. Mostly ethanol? Cheaper to buy at the hardware store?

 

[Zimbwanabe]

Wow, thanks E, I had no idea. That was the first week I owned it. I have a guillotine switch on the ground side, for when I leave it parked a long time, and as a kind of low tech theft deterrent. I've probably used it 50 times by now, so my next test will probably be screwed.

 

[NLXTACY]

Smog "hypothetical"

But from what I hear, rumors and innuendos of course, but its my understanding that...

 

[retrofive]

Smog "hypothetical"

But from what I hear, rumors and innuendos of course, but its my understanding that...

Are you saying e999999999999999 should drink it first?

 

[NLXTACY]

Are you saying e999999999999999 should drink it first?

and pour some for the homies we've lost.

 

[e9999]

so, what concentration of a drink would taste best exactly?

 

[NLXTACY]

so, what concentration of a drink would taste best exactly?

1:25

 

[surfpig]

 

[e9999]

and yet we already have 10% ethanol in our tanks...

 

[inkpot]

and yet we already have 10% ethanol in our tanks...

Ethanol/Everclear tastes a bit better!