Seeking emissions teat equipment near Tucson

[Knockenwelle]

It's that time of year again, when the leaves are gone from the trees, the critters are sleeping, and I'm locked in a battle to the death with the Arizona Smog Nazis.

Arizona says the car has to be under 220 ppm HC, and 1.20% CO, for both rolling and idle tests. I've taken the car through emissions twice already, and passed both rolling tests with ease, but both times had excessive HC readings at idle, though the CO levels are OK. The car has a Schrick 288, as well as some head work and a compression bump. It's got 2800 miles on it, so it's nice and tight. Uses no oil, and the oil is fresh. I've tried adjusting the fuel pressure, for starters. I've passed dozens of musclecars that had no business passing using tuning tricks and magic that work well for carbureted V8s, but I've not had any experience passing an ornery M20.

Do you all have any validated suggestions as to how to lower the HC levels at idle?

So far, I'm thinking about raising the idle speed by opening the butterfly and readjusting the TPS, but I'm thinking that might piss off the computer when it tries to set the idle speed and can't. Another thought is to replace the Dinan chip with the stock one, but I really don't know how much difference that will make. Another is to temporarily plug the breather hose, to prevent oil fumes from being burned. This will almost certainly help, but I'm not sure how much. I don't think I'm going to mess with the fuel much (adding ethanol), cause there's only so much tweaking you can do with the oxygen sensor trying to fight you. What about moving a couple clicks on the (M30) AFM?

I'm looking for someone in the Tucson area who has a reliable emissions tester I can use to measure the effectiveness of my ideas, but I don't know anyone in town anymore, and I don't want to just pay some random shop to use theirs. Anyone?

[Farbin Kaiber]

Maybe making sure everything is operating in it's designed and engineered would be your best bet. Many other members cars pass smog in Cali, so why not just give it a tune, some seafoam, a new cat, and call it a day. you will pass with flying colors.

[Farbin Kaiber]

Then I read you have a 288. Pull the cam, swap in the stocker, pass smog, replace 288.

[Knockenwelle]

That's what I'm trying to avoid... Though that's almost guaranteed to work. I have a new cat, EVERYTHING rubber and ALL gaskets underhood are new and sealed up tight and right, all sensors are working correctly, and the motor is fresh. I'm looking for tuning tricks...

[Farbin Kaiber]

Too bad Colegrove is gone. This thread seems right up his alley.

[nando]

Then I read you have a 288. Pull the cam, swap in the stocker, pass smog, replace 288.

that doesn't seem very realistic.

High HC means it's running rich right? are you using bigger injectors? new O2 sensor? OE or aftermarket cat?

I think bumping up the idle speed is the way to go - it should pull more vacuum and run smoother. the 288 really needs ~900rpm, the stock 700 or so is too low anyway. and no, the computer won't freak out, as long as the TPS has been adjusted so it thinks the throttle plate is closed.

you could also use an 80c thermostat to get the engine to run a little warmer, which should drop the amount of fuel being used.

If you could bump the idle timing 3-4 degrees, that would also have the effect of leaning it out. I would not put the stock chip back in though, I think that is likely to make it run worse.

[Farbin Kaiber]

that doesn't seem very realistic.

It's the norm for people whom are used to dealing with the air nazis.
Well, you guys are not in Cali. Here it's the norm to swap an engine out for a smog. I usually do my buddies LS1 Camaro every other year. (Gotta pull out the 502c.i. turbo engine and pop the bone stock 33,000 mile LS1 in for emmissions testing.) It;s a weekend gig.

[Knockenwelle]

High CO indicates a rich burn, while zero CO means a stoichiometric burn. HC is kinda just along for the ride, and is more an indicator of combustion efficiency (chemical and mechanical influences). Raising the idle speed will improve mixture quality otherwise degraded by cam overlap, thereby reducing HC. As long as the computer will live with a high idle like you say, I'll do this. Yes, I'm running 19lb injectors. Lowering the fuel pressure actually hurt readings across the board, so I'm thinking the computer richened the mixture to compensate for the "lean" burn the O2 sensor was reporting at cruise.

The O2 sensor is new, as is the Cat. It's a Magnaflow 2" dual, CA-approved.

Good idea on the T-stat. I'll pick one up.

How does one adjust timing on Motronic 1.3? I was under the impression that it can't be done other that with chips. Maybe I can pick up an extra CPS bracket and slot it?

[nando]

you cant adjust timing, other than a chip or adjusting the bracket as you said. This will also raise idle speed some so you wouldn't need to open the throttle plate as much.

as far as fuel pressure - you might want to go the other way. lower fuel pressure results in poorer atomization, higher is more efficient (new cars run much higher pressure than our E30s). I would bump it up to 3.5-4.0 bar and of course drive it around a good bit so the computer can scale back the injector PW to compensate.

[Knockenwelle]

So any thoughts on adjusting the MAF wheel?

How about emissions analyzer equipment?

[Farbin Kaiber]

Can't you just pay the 35 bucks to have them run the car but not submit the results? You won't pay for the certificate either.

[nando]

So any thoughts on adjusting the MAF wheel?

How about emissions analyzer equipment?

Well you could try to mess with it but unless you have a wideband you're just pissing in the wind. to be honest I would put the stock one on and see if you can pass with it.

[Knockenwelle]

Can't you just pay the 35 bucks to have them run the car but not submit the results? You won't pay for the certificate either.

I wish... AZ has state-run test facilities, not licensed independent shops. No cheating or bribes.

I thought about putting the stock AFM back on, but then there's the 19lb injectors...

[Knockenwelle]

GOT IT!!!

Passed this evening, 167ppm HC/.48% CO on a 220/1.20% standard. I raised the idle to about 1400 rpm and moved the TPS accordingly. Also unplugged the IAC and messed with the CO screw. This was the first smog test on the new motor, and I was getting a bit nervous that it wouldn't pass. But now...another whole year of terrorizing underpasses!! Giggity!!

[nando]

wow they let you pass with a 1400rpm idle? well, whatever works! :)