marcucci

I've been on a mission to find out what the new emissions testing levels are for North Texas which go into effect for Dallas, Tarrant, Collin, and Denton counties on May 1st. Despite my tries, I have found squat on the internet other than the testing will be OBD2/ASM2 compliant.

I FINALLY found someone at the state DPS office who could help. This is what they told me:

"Vehicles equipped with OBD2 computers after 05/01/2002 will be OBDII tested, meaning that the computer will check for any emissions components malfunctions. If there have been no diagnostic codes set in your cars computer - then you pass the emissions test.

For pre-OBD2 it will get the ASM test (new dyno test) this is where the cutpoints come in to play. The cutpoints are actually set by the EPA and are a pain to decipher. "

Some additional info:
- All 1996 and newer model vehicles sold in the US have OBD2.
- Some 94 and 95 models have it, though these are few in number and NO Hondas from these years have it.
- Read more about OBDII testing:
http://www.txdps.state.tx.us/vi/Misc/all_obd.pdf
- Read more about the ASM2 test:
http://www.txdps.state.tx.us/vi/Misc/all_asm.pdf

It turns out that the new limits for the dyno (ASM2) testing are much stricter than before. They vary based on year/GVW and are tabulated (no way to just calculate it).

Update:
Here's where you can read all about the testing:
http://www.tnrcc.state.tx.us/oprd/sips/ASM...M&TSI_Specs.pdf

Careful, it's a 702-page document! The formula/tables for the ASM (dyno) testing or NON-OBD2 emissions levels are on pages 662-6892, Appendices S and T.

Here's what I have so far:

1991 Trooper, 3755lbs:
HC
5015 117ppm
2525 111ppm

CO
5015 .65%
2525 .63%

NOx
5015 879
2525 796

Where 5015 is 50% load at 15mph and 2525 is 25% load at 25mph.

I believe the old test was along the lines of 220ppm HC, 1% CO, and 1000 NOx tested at idle and at 2500 RPM. Big change. I'm trying to get other year/GVW combinations and will edit this post as they come in.

I'm VERY interested in this as my truck seems to have lost it's smog pump, EGR, and catalytic converter. I don't want to have to go and find them if the standards get any stricter.

RyanDL

Where do you get your car inspected? I've never had anyone sniff the emissions on any car my family has had inspected in North Texas. I don't think my friends have, either.

Ryan

marcucci

Tarrant and Dallas Counties require sniffing, have since '95 or before, I believe. Denton, Collin, etc., have not. May 1st it all changes, due to the TX Clean Air Act. TX is in danger of losing highway funding, so most counties around most major cities (D/FW, Houston, SA) will be testing to much tougher standards (above). Others will follow within a year or so.

The old standard was a simple test that applied to all cars regardless. This new one is based on year and gross weight. I suspect a lot of cars will be failing, especially heavily modified ones. Catalytic converter sales will undoubtedly be going up.

RyanDL

Hmmm... That's a bummer since I now live in Dallas County. Looks like test pipes are out of the question!

Ryan

marcucci

Only for when you test. I hear they will start doing sniff tests on the road (or better, infrared ones) but I haven't heard of anyone getting a ticket yet.

The cat swaps fairly easy, especially if you anti-sieze the bolts. I'm also thinking of an experiement to determine if there's a way around the OBD2 testing, since they rely ENTIRELY on the ECU for the emissions testing (no sniffing/dyno).

TXRacer

I see emissions-testing crews set up on the ramps at the LBJ/DNT interchange all the time. My bet is they've been testing whether all the Collin and Denton Co commuters coming down the DNT are meeting emissions standards.

I'm glad we won't have to do dyno tests; that will save a lot of time and money.

Elistan

Is that what those are? Wow, I probably peg their sensors - if the traffic is clear, I'm usually a bit above 6000rpm in second gear, going towards WOT at that point.

TXRacer

A couple months ago, one team had put up signs up that said "EMISSIONS TEST" and "DRIVE NORMALLY". The S2k is pretty clean, even at WOT, so I'm not worried about the tests. We are a LEV, which means we're at or below 50% of the maximum.

Schatten

This is interesting - I remember years ago some city counselman in Houston had a great initiative on his "made up" bill that would require cleaner air in Houston. He built up several (I think 6?) emmission testing facilities and wasted a lot of money. They had free testing before the date went into act and after it went into practice, it went under due to some falsified papers and documents that would say Houston was required to do anything.

Well, anyways... I took my 88 Mustang LX with modified everything - except the long block. No cats, no smog pump, among other anti-smog related items which were bypassed. And yea, the exhaust smelled bad. Thing is... I came much closer to passing than a friend's Oldsmobile wagon did. For me, it was just one digit off which was very minimal - it probably could have been cured by better gas or even a hotter running engine.

I hope they have the proper testing equipment on hand.

Elistan

Acording to this https://www.s2ki.com/forums/showthread.php?...&threadid=53659, while we don't burn hydrocarbons or NOx, we produce quite a bit of corbon monoxide at WOT above 6000rpm: 8.5%, as opposed to the legal limit of <1%.

Lucky for us, this doesn't trip an OBDII error.

Can OBDII scantools reset errors? Randy, you have one, right?