WDRacing wrote:Here's a quick recipe for a pass, do all of these steps and you should pass if your using any type of cat.
Mark your distributor, so you can reposition later. The retard the timing quite a bit, all the way if you want. Run your car down to about 4 gal of gas, then add 1 gal of denatured alcohol. Turn the idle air screw out till the idle is about 1200 rpm. Drive your car till the engine is completely warm, I suggest 30 minutes. Prior to getting the test done, remove the #1 injector wire, this will cause your car to idle like crap, but it will still run. The increased idle speed will also help. With the injector not firing that cylinder is pumping fresh air into the exhaust stream. The effectively raises your AF mix about 2 points, the alcohol burns without releasing hydrocarbons.
Thats every trick I know wrapped up in one package.
Best of luck...
I like your thinking...I may have to try this method after my engine is rebuilt and I have a different MAFS, ECU and fuel injectors.
It's been a while since I passed, but I retarded my timing to like 12 deg btdc, lowered my fuel pressure to about 29 psi (it's supposed to be 34 psi), used about 20% pure methanol mixed with 94 octane gas, had a catco high flow cat, and had ALL of my emissions stuff still connected, including the EGR crap. It barely passed...and by barely, I mean it was 6 parts per MILLION within the limit for NOx.
You have an S-AFC though, so I'm sure you can program it to lean the car out at certain RPMS. IIRC, they don't go past 3000 rpm during the test, and I believe it's done while NOT in gear.