Emissions - I need 1 more PPM lower!
 

Installed two brand-new direct fit catalytic converters last night on a freshly-rebuilt engine (~4200 miles now) on the '89 GTUs (non-turbo).

Tried to get it smogged at my usual shop this morning, their dyno was not operating so I went down the road to a Test-Only place (not required for me) that had time before I had to be at work.

Low speed test--
CO2 - 14.1
O2 - 0.7
HC - 119 (max 118, ave 31) FAIL by ONE PPM!
CO - 0.08 (max 0.75, ave 0.10)
NOx - 64 (max 799, ave 237)

High speed test -
CO2 - 14.3
O2 - 0.7
HC - 86 (max 93, ave 20)
CO - 0.07 (max 0.63, ave 0.09)
NOx - 43 (max 738, ave 199)


I will try again tomorrow, if the new cats are not already burned out by then. I had just replaced the main cat with a new one about 1K miles ago, we pulled it off and it was already toast.

I plan on putting brand-new plugs in right before the test, doing a lot of pre-heating on the cats, and possibly changing the oil tonight, as I am running a slightly thinner viscosity than most guys (but it is what the engine builder recommended) and it is near the end of its drain interval.

ALL I NEED IS ONE STINKIN PPM LOWER OF LOW-SPEED HC!!!

Any other suggestions other than the FAQ emissions thread? I will not put alcohol in the fuel tank, I don't feel that the risks for damaging the new (and $$$$) cats and/or engine, and just one ppm is not worth it.

EDIT -- I know that the timing is off, and that the AIT sensor is dead, but we can't seem to find a set of wires and/or a timing light that can get a signal (stock new NGK wires), and the air temp sensor is not available through regular auto parts stores, and even Mazda Competition cannot locate new sensors.....

Thanks,

-JW

Straight out of the sticky FAQ:
My car is having trouble passing emissions, but I have new spark plugs, filters, cats, etc. What do I do?
High HC, Low CO/NOx: Run-in Converter, tune-up, oil change.

and:
J-rats Recipe for cheating emissions if its ABSOLUTELY necessary:

1. Turn variable resistor to full lean, or as lean as you can get and still run.
2. Trick ACV into pumping air to the cat all the time by removing the FORWARD UPPER vac hose, and capping it.
3. Run 87 octane
4. Run your tank down till your almost empty.
5. 2-3 bottles of alcohol in the tank. Drive VERY GINGERLY to the emissions station.
6. Once you pass go, DIRECTLY to a gas station and fill up with regular unleaded.

Anyone have a photo of this vacuum hose trick location, marked on the photo? I would hate to cap the wrong one....

-JW

1PPM could be a variance caused by almost anything. Temperature, slight misfire, wind blowing onto the engine, etc.

However...

That will do it. The car MUST be in proper operating condition before an emissions test is taken. Both the timing and the IAT sensor will effect the emissions. Depending on where the timing is set you will either get excessive HC or excessive NOX. The IAT can make the car run rich, depending on how it fails.

I'm surprised that Mazda cannot locate the parts. Grab a copy of the parts catalog from the links in the FAQ, look up the part number and give it to them. Don't believe any crap about them not being available since I could go to my dealer today and order hundreds of IATs without a second thought. :)

Things I would do (in order) since you are so close to passing:

New spark plugs
New air filter
New oil (use something thick, like 20W50-instead of the 15W40 you have been, you'll get less blow by)
Air pump to directly feed main cat

Since you are so close I would not even try and mess with anything else.

AIT number N326-18-845, the guys at the Mazda Competition Department in Irvine are usually the best way to get ahold of parts, I trust them more than local dealers, and they have access to parts warehouses across the country. If Tim says he can't get them for me, and then two of my local Mazda dealers can't get them for me, I am lead to believe that I am temporarily SOL. If you can get them for me, then I will buy them from you! :-P

Icemark, I will do the plugs and oil change, air filter is a new RB foam filter. I am still interested in doing the air pump feed trick, but I am usure of which vacuum line to cap....does anyone have a photo with an arrow? I won't be able to get out to the RX-7 until this evening, but if it is a trick worth doing, I am game.

Any tricks to getting the timing light to pick up the signal? I have been told that I should get a cheapo set of $10 wires to set the timing, and then put the NGK wires back on, as apparently they are "too shielded" to read a spark signal on 4 different timing lights.

-JW

yeah just change the oil, if you have a cone air intake, remove it for the test,

as far as the air filter, foam filters if they are the least bit dirty will often cause a running rich situation on a non turbo... its the oil or what ever that is impregnated in the foam that gets sucked in. Maybe a K&N cone might be better for the test.

I am not familier with the vac line thing, I just get a piece of schedual 80 3/4" ID PVC and hook it up between the air pump output and the check valve for the air supply line for the cat, for just the test. But as I recall there is only one vac line on the ACV. S5 models just are not my forte so I don't remember off the top of my head.

I have not had problems with using Jacobs spark wires or cheapo Accell spark wires. You may have to just swap the front leading line with a POS Pep Boys special spark plug wire to time it.

Passed this morning, did an oil change, new plugs (the old ones were perfect, though!), and heated the cats up pretty good with a few minutes on the freeway.

Thanks guys!

-JW

Try this.
Add 3oz. to 10 Gal. ratio of PURE Acetone to fuel.