Adventures in Smog Check :(

[Guest Anonymous]

So I went to get my 87 BMW L6 tested yesterday afternoon at the local Smog check place. Unlatch the hood and the tech opens it up, then has to get in it to put it on the rollers (I wasn't quite lined up right).

He backs up. Goes over the rollers and the hood comes crashing down.

I'm a bit in shock and don't really say anything.

"Sorry" he says.

He runs the car through the test, passes. Then proceeds to drop the hood from like 2 feet up. [clang]

Me again

Then he starts PUSHING on the hood because it obviously has not auto-seated and latched correctly and is sitting up slightly.

I quickly run over and say "Arrrggg, It's a latch on the inside, please stop pushing on my hood!"

:|

He did tell me something interesting about cat converters I didn't know before--I guess they have to get pretty hot to work effectively (my NO was passing, but kinda high for a new cat) and suggested next time to run it for a while before coming in to get it checked.

No, I will not be going back to him to get it re-checked in 2 years.

[Guest Anonymous]

Other than keeping the cars in best possible tune:

1. I run a can of "Smog Check in at Can" for a tankful prior to the check.

2. Before going to the check station I run the car with air-on full blast and a blanket over the radiator to get the heat way up. I then go to the check station.

3. Pray. I drive a '97 Dodge truck and an '94 Infniti Q45 when not driving the 02, so it just a matter of time before the CA Smog-Nazis decide that those cars shouldn't be on the road.

[Guest Anonymous]

NOX is related to combustion chamber temperature, which relates to engine temp, which relates to air flow through the radiator during the test. They can vary the NOX results by forcing air through the radiator during the test (that big fan that they have sitting in front of the car!). If NOX is related to the cat, its the first time I've heard that.

[Guest Anonymous]

Maybe it wasn't NO. He just pointed to a high number and talked about making sure the cat was plenty warm before coming in.

Either that or he was full of crap. Both seem plausible at this point.

[Guest Anonymous]

Actually according to this site

http://www.uyseg.org/catalysis/catalytic/cat1.htm

three-way cats do cut down on NOx. I don't know the first thing about cats or smog, since the only cars I ever worked on myself were pre-74.

[Guest Anonymous]

Getting the cat hot makes it work more effiecently and will clean up CO and HC issues better than if it were cold.

NOX is a product of combustion temps so getting the engine hotter by covering the radiator is probably not helping...but drive the car around in low gear and high rpm before the smog and it will help heat the cat and clean it up, without raising engine temp as much...especially if you are borderline...

Problem is nowadays with the smog tests taking so much time with the idle test etc...the cat cools down.

When I wrenched and had a smog license I used to take the cars out and put them right on the machine...

The cleanest runnnig 02 in world still pollutes 200 percent more at 10 minutes idling than a new car does running all day...

[Guest Anonymous]

For those of us who love our classic rides but also would like to be as environmentally friendly as we can, is installation of a catalytic converter an option? Why would it not work, unless there is so much to reburn that it would melt?

[Guest Anonymous]

CARB considers the CAT to be part of the body of the car and not the engine. This is why you can install a 320i/318/M3 motor into an 02 in California and NOT need to install a cat.

You DO need to install an 02 sensor as that is considered part of the engine and emissions equip.

When you update the motor, you have to meet the smog requirements for that year motor.

[Guest Anonymous]

A cat needs to stay hot, so it needs to either be as close to the engine as possible or have an air line plumbed back to it to help heat it. Both ways would need heat sheilding galore, but there are high flow cats that are very small these days.

[Guest Anonymous]

Go efi and electronic ignition. Then you could cut emissions way down me thinks.

[Guest Anonymous]

From my reading and paying attention to it over the years, my impression is that it's more a case of cylinder head geometry than ignition. But of course a truly weak ignition will dump unburned HCs out the tailpipe. Good way to burn out a cat too.

[Guest Anonymous]

I've been smogging an '84 LH-Jet Volvo for about 14 years now, and it's never failed. In fact, with a quick tune up it comes in at about 1% to 10% of the maximum emissions, and well below the average for the year and model. It will even pass late '90s standards. Once I passed an emissions check and was surprised that the CO reading was fairly high, nearly at the limit. Later I took the catalytic converter off and found out that it was hollow! Apparently the element had disintegrated, but the motor ran clean enough to pass anyways. Even at 300k miles, a quick tune up guaranteed a pass with flying colors.

My wife's M42 D-Jet '91 318is E30 always passes with a huge margin to spare, with 130,000 on the motor.

The 'secret' with most EFI cars is that they have a built-in smog check station in the form of an oxygen sensor. Even the early closed-loop models have a test port that can be read using a voltmeter. If the O2 sensor readings are OK, you will pass the smog check (unless the cat is shot, which might cause it to fail). Later cars will report system faults through the on-board diagnosticsj if you can read them, you just have to replace faulty components as indicated, and then you will pass smog.

I love transistorless cars, but there's something to be said for EFI.

Mike

[Guest Anonymous]

(nt)