Passing Smog Test.

[jlevie]

An E30 whose engine is in good condition and is operating properly should come darn close to passing an emissions check even with no catalytic converter. Doing what is necessary to make the engine run right allows the car to pass an emissions check and as a bonus the engine makes more power and gets better fuel economy. So you gain a benefit all year and don't have to struggle with an emissions test.

The first thing I'd do would be to get compression and leak down numbers. There's little point in putting a bunch of effort and coin in a worn out engine. If the numbers are decent I'd replace all of the rubber bits associated with the intake and then smoke test the engine to find leaks and fix those. I'd have the injectors cleaned, rebuilt and flow tested and check rail fuel pressure. Replace the plugs, ignition wires, distributor cap, rotor, and O2 sensor. Verify that the engine temp stabilizes at idle very close to 80C and verify the ECT sensor's operation. An engine with up to 150K can get by with just a valve adjustment. Beyond that I'd pull head have the valves ground, a light surface cut and install new seals installed.

If the engine has been running rich or burning oil, the odds are that it will need new catalytic converters. The excess hydrocarbons will overheat and damage the matrix. In addition to what that does to operation it also introduces a restriction in the exhaust and affect performance.

[dnguyen1963]

FYI...

http://www.youtube.com/watch?v=5icTmYItwiE&feature=related

[e30trooper]

get the cat has hot as possible. Run some 91 and get a oil change. You want your cat to have that ticking sound when you turn it off.

[Eurospec]

Running 91 octane is important as is an additive. I'd spend a few bucks more and opt for BG44k. That stuff is great. Just be sure to do an oil change shortly after.

You can buy BG products locally at Northridge Tire & Service on Reseda, north of Parthenia.

However as others have mentioned... a tune up shouldn't be overlooked. There's only so much higher octane gas and an additive could do.

Good luck!

[Mo_E30]

Tune up...New cats, New sensors seem to help.

I was actually looking to have the cats checked out in the morning.

Schedule smog check.
Dump a can of techron or BG44k in your tank (1/4 or less filled).
Drive car to nearest Chevron, pump a gallon or two of 91.
Go on spirited drive-- highway preferred. Try not to get pulled over. Doing this mid day, if at all possible would probably work to your advantage.

Now the key to all this is that you drive into your smog check w/o turning off your engine. Confirm with the checker if you can do this prior to scheduling your appointment.

Had success doing this recently with an e36. Let me know if you need the info to the test only center I took it to that allowed me to drive in with an appointment. It's in Northridge, not too far from where you are.

Thanks for the sound advice.

Today, I did the Smog Test on a cold start because I passed it easily six months ago. After it failed, I was highly disappointed and directly visited my mechanic who told me to drive it on the highway while maintaining it at above 4k RPM for about 20 minutes. I did exactly that and returned for my free second try test, which also failed with minimal improvements. In fact, my schedule was so on point that as soon as I pulled up the car was on the dyno.

How positive are you about passing with the addition of Techron and 91 octane?
Would it be a waste of money to try or should I be safe and just replace the cats?

Frustrating scenario.

I'm no pro but I'd inspect the rubber piece that goes from the throttle body to the afm first especially if that thing hasn't been touched for a long time. When I first bought my car I barely passed, I mean I was within 0.5 of the max across the board, when I smogged it last, I just did the water pump and coolant hoses and the rubber intake boot. Pass but this time really close to the minimum #s

Edit; Make sure you run your car a while before actually getting it smogged, it helps keep the numbers down.

I actually recently replaced the water pump, radiator, timing belt and spark plugs. I'll ask my mechanic about the throttle body though. Thanks.

[MR 325]

Contrary to popular belief replacing the cat (or cats) should be the last resort. If your car has an OEM BMW cat it's probably NOT bad unless a poor running engine has made it bad. As said check plugs, cap, rotor, fuel filter, oil change, etc.

[ohthejosh]

Now the key to all this is that you drive into your smog check w/o turning off your engine. Confirm with the checker if you can do this prior to scheduling your appointment.

Lol, I was a little late to my appointment at a smog station and they had someone take my spot, I just sat in the car running.

[ohthejosh]

I'm no pro but I'd inspect the rubber piece that goes from the throttle body to the afm first especially if that thing hasn't been touched for a long time. When I first bought my car I barely passed, I mean I was within 0.5 of the max across the board, when I smogged it last, I just did the water pump and coolant hoses and the rubber intake boot. Pass but this time really close to the minimum #s

Edit; Make sure you run your car a while before actually getting it smogged, it helps keep the numbers down.

[Eurospec]

Schedule smog check.
Dump a can of techron or BG44k in your tank (1/4 or less filled).
Drive car to nearest Chevron, pump a gallon or two of 91.
Go on spirited drive-- highway preferred. Try not to get pulled over. Doing this mid day, if at all possible would probably work to your advantage.

Now the key to all this is that you drive into your smog check w/o turning off your engine. Confirm with the checker if you can do this prior to scheduling your appointment.

Had success doing this recently with an e36. Let me know if you need the info to the test only center I took it to that allowed me to drive in with an appointment. It's in Northridge, not too far from where you are.

[reelizmpro]

Tune up...New cats, New sensors seem to help.

[Mo_E30]

Have any of you had trouble passing the Smog Test in California?

What is the best solution to this problem? Any recommendations would be appreciated. :)