Cal Club Autocross Forums

Stock 95m3 is due & it should pass, but to get a little edge:

Really heat up the cats, but then you may need to wait in line & it cools down.

Unleaded race gas.

A bottle of the "Guarantee pass" mostly some type of alcohol I think

Oil change.

Anything I missed?

Thanks.

PS New head/plugs recently done.

What's behind the race gas? High octane doesn't burn as completely as lower, and you're not going to be tested at full load (where the low octane would pre-ignite).

I'd just run it hot with the new plugs. Most places let you re-test for free. If you run all your tricks, you might get a low score and not know there's a pending problem.

Jay W

The high octane is just something I heard, no idea if it works or not, maybe not.

Thanks.

Any other ideas?

Clean or replace air filter.

Michael Sullivan wrote:Clean or replace air filter.

Check, thanks

If it cools down while you wait, hold the rpms up to 3k or so for 5 minutes. That should heat them back up.

Tom Berry wrote:If it cools down while you wait, hold the rpms up to 3k or so for 5 minutes. That should heat them back up.

Thanks Tom

My experience has been that when a car passes, it passes by a big margin. When it fails, it fails due to an actual fault, not creeping emissions. Stuck relay, plugged EGR orifice, leaking gas cap, loose vacuum hose, that sort of thing. So the only prep that would make sense to me would be a pre-check that doesn't count against you if it screws up big time. Important to never become tagged as a gross polluter because that tends to stay with you.

But I live in a rural county and my smog tests are less severe than most of yours. So YMMV.

If you have any doubt, pre-test. Air filter, fresh plugs, maybe fresh wires. Drive the car for an hour ahead of time to ensure full heat soak of all components. Oil change shouldn't matter unless your valve seals are leaking a lot, as in the car smokes like an Arab at hookah bar*.

*Note that Arabs enjoy smoking tobacco with a hookah and that I only cite this as an example related to the amount of smoke.

Thanks guys Bills post makes a lot of sense. I an concerned about the pressure test on the fuel system & I thought with those miles the cat could be getting weak & hence maybe miss the mark by a little.



Will try to find a place that has a pretest policy.

This was news to me. I recently "failed" a smog test because only one of three monitored circuits registered as ready. They had all reset because I disconnect the battery in my Jeep between runs. Connecting the battery and driving down to the smog shop didn't get it done and while there were no faults, I couldn't pass until two of the three monitored channels registered as ready. I had to drive it nearly 100 miles to get the second one on line. Memo -- don't change/disconnect your battery just before smog check time.

Bill Martin wrote:This was news to me. I recently "failed" a smog test because only one of three monitored circuits registered as ready. They had all reset because I disconnect the battery in my Jeep between runs. Connecting the battery and driving down to the smog shop didn't get it done and while there were no faults, I couldn't pass until two of the three monitored channels registered as ready. I had to drive it nearly 100 miles to get the second one on line. Memo -- don't change/disconnect your battery just before smog check time.

I have heard of this on later model cars.

Bill Martin wrote: Memo -- don't change/disconnect your battery just before smog check time.

Clearing codes with a code reader will also put the ecu into "not ready" status.

Bob Pl wrote:Stock 95m3 is due & it should pass, but to get a little edge:

Don't know if your car would pass smog but assuming all the stock emission parts are on the car and in working order, just drive the car hard (say some nice twisty canyons in San Diego) or hop on the freeway, for about half an hour. Then go to the smog station and if waiting in line, see Tom Berry's reply below:

Tom Berry wrote:If it cools down while you wait, hold the rpms up to 3k or so for 5 minutes. That should heat them back up.

That should pass you. That's what I do on my Stock 02 M3.

p.s. - Eric also makes a good point (as I have the Peake reader). Do NOT reset anything 'til after the test.

Thanks Gio,



Hot it is.

Maybe pull the fuse on the fan.

Wonder if it can be hacked to come on at higher temps?

}:)

No, don't get the motor too hot, it will result in Nox going up and failing you. You want CAT to be hot, not the motor. Motor should be at normal operating temp.

How many miles on the CAT/ 02 sensor?

Max Likhterman wrote:No, don't get the motor too hot, it will result in Nox going up and failing you. You want CAT to be hot, not the motor. Motor should be at normal operating temp.

How many miles on the CAT/ 02 sensor?

It's got about 140k.

Thanks.

I've had good luck by replacing the air filter, spark plugs, PCV valve, and getting the cat good and hot. If there is a line, I drive around and come back.

Sebastian Rios wrote:I've had good luck by replacing the air filter, spark plugs, PCV valve, and getting the cat good and hot. If there is a line, I drive around and come back.

Thanks Seb

http://i125.photobucket.com/albums/p70/ ... 110000.jpg

Link to the results, passed. Hope it's legible, best scan I could figure out.

"High emitter profile" sends this to test only, maybe all m3's are profiled this way.

If you are knowledgable about these percentages & would like to comment, please do.

It looks like the low speed NO reading just squeaked by. Yikes!

I think my concern was warranted. What would cause such a high NO reading at low speed & how to "fix" it?

I think my other more mundane vehicles pass with much lower percentages (of the averages) than this m3.

Thanks all for the tips. I put a half tank of Shell premium & a bottle of techron & ran it for about 45 min at 80 on the fwy just b4 the test. It sat for about 20 min (cool down) before the test.

I watched & did not see any pressure test of the fuel lines/tank/evap canister and I wasn't going to ask about it although the fuel lines were replaced when I had the head done.

Bob Pl wrote:I watched & did not see any pressure test of the fuel lines/tank/evap canister and I wasn't going to ask about it although the fuel lines were replaced when I had the head done.

This test appears to have changed over the last year or so based upon my observations, smoging 4 times in the last year. Apparently "newer" (what ever that is, our '02 Jetta fell in this catagory) cars no longer get tested, older ones (the '95 Miata fell in this group), have the cap tested off of the car, and even older ones yet (Our '91 Integra, RIP) get the cap off test, along with a new one directly on the fuel neck filler.

Why, they differ, or what makes cars of a certen age require more testing is beyond me though, and I haven't the time or inclination to look it up.

Thanks Craig.

NO comes from high combustion temperature. I can only guess why it's higher than normal. Lean fuel mixture or the thermostat / cooling system allowing the engine to run hot could cause high combustion temperatures. A failing catalytic converter would remove less NO than a new one would. That's all in theory. Someone who sees a lot of smog results and diagnoses the problems might be able to tell you what's most likely based on your readings.

John Stimson wrote:NO comes from high combustion temperature. I can only guess why it's higher than normal. Lean fuel mixture or the thermostat / cooling system allowing the engine to run hot could cause high combustion temperatures. A failing catalytic converter would remove less NO than a new one would. That's all in theory. Someone who sees a lot of smog results and diagnoses the problems might be able to tell you what's most likely based on your readings.

Thanks John,

The complete cooling system is about 1.5 year old & so far as I can tell in perfect shape. I put it in when I got the car. Stock.

If you can believe the oem gauge it's 100% in the normal.

It was a coolish day say 65-70 but I do recall the tech did NOT put a fan in front of the car. The car does have a functioning elec fan.

On the BMW forum(s) it has been noted that higher mile e36's tend to higher NO.

Some recommend a used e46 cat/midpipe being better than an e36 new replacement.

Or weld in an aftermarket cat.

I looked into the crc gaurantee pass stuff but IMO it's no different than Techron or Redline (all go in the tank & clean up deposits). It's a stupid gaurantee, you have to fail, make repairs, pass, then mail all that paperwork to crc to get $10. back. Sure. Marketing BS

Any one else?