It's SMOG time - Questions about Gas Caps & C/O Mixture & Timing Advance

[Ryan King]

Also the tank pressure test is not only the cap.

They actually took our caps off and pressure tested them. California is ridiculous.

[Ashyukun]

They actually took our caps off and pressure tested them. California is ridiculous.

Dang. That's patently ridiculous. Makes me all the more glad I live in a state that doesn't require emissions inspections (though to my annoyance I still can't find a shop that will put the new cat-less exhaust system on... -_- ).

[TTait]

I can't believe they check ignition timing.

Also the tank pressure test is not only the cap.

In CA they do not check pressure at the tank, they just take the gas cap and hook it up to a vacuum hose to see if it seals well.

My guy just asked me if I knew what the timing was, and typed it in.

[David T]

Here in New Jersey they used to check (or at least try checking) the gas cap. I would always fail and they let it go. Eventually an edict came down from on high that the stations did not have the proper adapter and that they could no longer test the gas cap (at least for Deloreans). The used to pressurize tanks but after blowing up some they only test newer cars. If you are having trouble passing NOX and you have non-standard cams you can try adjusting the timing, that should get you to pass. It will probably degrade the power so after passing the test you may want to reset the timing. Make sure you have fresh fuel in the tank for the test.
David Teitelbaum

[Masaes727]

Dang. That's patently ridiculous. Makes me all the more glad I live in a state that doesn't require emissions inspections (though to my annoyance I still can't find a shop that will put the new cat-less exhaust system on... -_- ).

you need to goto Eastern Kentucky for that, i.e. Maysville or come up here to Indy and we can get it done.

[Agent Smith]

Just to clear some things up:

1) California now does a low pressure evap test. This involves pressurizing the entire fuel system. There's a provision in the rules that if the evap cannister isn't accessible the tech has discretion in not performing the test. However, since the evap line is accessible, most techs will still do the test if they figure out where the line is.

2) Timing is checked.

3) The OP's test results show his engine to be in fuel control. Therefore the high NOx is due to something other than a non-stoichiometric feed gas.

[Bitsyncmaster]

2) Timing is checked.

You can just move the timing plate if you want to keep a non-standard timing. I don't imagine they check TDC

[Agent Smith]

I'm simply saying it's part of the test protocol. I always test these cars before they go in and that includes the evap. My experience has been they all leak like sieves until corrected. With a little effort they can be made tight through.

Btw for all who think Cali is tough on smog it's far from being worst. Try living in a state that does the IM240 Drive Cycle rather than the ASM Loaded Mode. Furthermore, enhanced testing with the ASM is only done in urban parts of the state. Most residents get to do only the Two Speed Idle test and those who live in many places don't have to test at all until a car changes hands. It may not be fair but that's the way it is.

[Chris 16409]

Before I break down and decide to take my car to a shop to be looked at, I decided to buy a Dwell Meter from Sears to take some readings. Here's the one I bought:

http://www.sears.com/shc/s/ProductDi...=1316486793564

A note on this particular meter. Normally you are supposed to set the meter to the 4-Cylinder mode. However, this meter just has two scales printed on the face of it. One is for 6-cylinder engines and the other is for 8-cylinder engines. You simply double the 8-cylinder scale to get a 4-cylinder reading.

Initially, I was under the impression that my car was running lean, but it seems I discovered it was quite the opposite. Once the car had warmed up and I was getting the swinging needle, the meter read between 10 and 20. From what I've gathered on the forum and speaking with Dave a DMC-MW, the needle should be swinging between around 35-40. So i thought, well I must be running lean. However, to bring the swinging needle in that 35-40 range, I had to turn the mixture screw counterclockwise. This didn't make sense to me, why would I have to lean it out to make the needle read higher? After speaking with Dave, I learned it was reading between 10 and 20 because the car was actually set too rich, and the computer was trying to lean the mixture out.

So, It seems I have it set correctly now, and I hope having done this will allow my car to pass smog. I may still take it to a shop and have them hook up a wideband O2 sensor to see if I'm holding 14.7 AFR. The link below is a video I took of the dwell meter taking a reading on my car.

http://www.youtube.com/watch?v=MbE-2k4Cy4E

[Chris 16409]

It looks like the DeLorean Gods were smiling down on me today, I passed my SMOG test! It appears that the adjustments I made were good enough to pass. Crisis averted until next time. It's funny because when I retested at a different shop, they didn't have adaptor for the gas cap, and he just passed it.