Bill, I don't understand why you changed any of the equipment. Was it clear that the cat. or pre-cat. was bad? Or did the car fail in stock form? Here's what I would do:

1. put back stock cat (and precat if you so desire, but not necessary.).

2. New plugs (especially new BUR7EQP's in Leading)

3. Put stock O2 sensor back (Aftermarket O2's aren't as accurate)

4. Clean out black plastic purge tank

5. Run car hard on freeway for ~30 minutes or so.

6. Do not let car cool, keep motor running until test.

7. Make sure ALL electricals are off during test (turn off lights, fans, A/C, stereo, anything with electrical drain).

8. Also many forum members have run denatured alcohol in their tanks to help them pass, this is an option.

If you do these 8 things I'm pretty sure you'll pass with room to spare. Please post if there was something wrong with your stock equipment.

eric

I am confused. Wouldn't 9's have a bigger spark igniting more fuel? Not doubting you at all... Just curious as to why 7's and not 9's.

Please explain.

-- Eric

Thanks to GoRacer for setting me straight.

For others that don't know. :eek:

Specifications: BUR7EQP

B= 14mm Thread Diameter
U= Surface or Semi Surface Discharge Type R= Resistor Type Plug
7= Heat Rating *
E= 19mm Thread reach
Q= 4-Ground Electrodes (Firing End Construction)
P= Platinum *A spark plug's heat range has no relationship to the actual voltage
transferred though the spark plug, Rather, the heat range is a measure of the spark
plug's ability to remove heat from the combustion chamber. The heat range
measurement is determined by several factors; the length of the ceramic center
insulator nose and its' ability to absorb and transfer combustion heat, the material
composition of the insulator and center electrode material.

The insulator nose length is the distance from the firing tip of the insulator to the point
where insulator meets the metal shell. Since the insulator tip is the hottest part of the
spark plug, the tip temperature is a primary factor in pre-ignition and fouling. Whether
the spark plugs are fitted in a lawnmower, boat, or a race car, the spark plug tip
temperature must remain between 850-1500 degrees F. If the tip temperature is lower
than 850 degrees F the insulator area surrounding the center electrode will not be hot
enough to burn off carbon and combustion chamber deposits. These accumulated
deposits can result in spark plug fouling leading to misfire. If the tip temperature is
higher than 1500 degrees F the spark plug will overheat which may cause the ceramic
around the center electrode to blister and the electrodes to melt. This may lead to
pre-ignition /detonation and expensive engine damage.

The firing end appearance also depends on the spark plug tip temperature. There are
three basic diagnostic criteria for spark plugs: good, fouled and overheated. The
borderline between the fouling and optimum operating regions is called the spark plug
self-cleaning temperature. The temperature at this point is where the accumulated
carbon and combustion deposits are burned off.

Bearing in mind that the insulator nose length is a determining factor in the heat range
of a spark plug, the longer the insulator nose, the less heat is absorbed, and the
further the heat must travel into the cylinder head (rotor housings) water journals. This
means the plug has a higher internal temperature, and is said to be a hot plug. A hot
spark plug maintains a higher internal operating temperature to burn off oil and carbon
deposits, and has no relationship to spark quality or intensity.

Conversely, a cold spark plug has a shorter insulator nose and absorbs more
combustion chamber heat. This heat travels a shorter distance, and allows the plug to
operate at a lower internal temperature. A colder heat range can be necessary when
the engine is modified for performance, subjected to heavy loads, or is run at high
rpms for a significant period of time. The colder type removes heat more quickly, and
will reduce the chance of pre-ignition/detonation and burn-out of the firing end. (Engine
temperature can affect the spark plug's operating temperature, but not the spark plugs
heat range).

The NGK heat range is from Hot (2) to Cold (10).

Reprinted from the NGK Product Catalog.

GoRacer,

No free retests at Test-Only stations. $29.75 if you fail, $38 if you pass. Every time. (The $8.25 is a DMV document fee only if the car passes.) I'll try to get hold of Tri-Point, thanks!

hapa,

Changed parts because existing parts failed smog test, and I would like to register the car for next year! Yes, the car was in stock form, as I wrote. It was and is not clear what was bad, and will not be clear until it passes. (However, my Miata had about 70K miles on its cat and failed; I replaced it and it passed with flying colors.) Also notice the measured emissions in my original post: Great improvement in CO (which had failed) and NO with the new cat, new O2 sensor, and no precat. So that part of the change worked.

Problem is that at 25 mph the HC, which barely passed on the stock car, increased by 69% with the new cat/DP.

1) I am NOT putting back the stock cat.
2) I was having plugs changed, but the Irvine tech said they are fine.
3) I think the new Bosch 11027 O2 sensor is fine; I use the Bosch sensor on the Miata and it is fine there too.
4) thru 7) I will try all this stuff (if I can find the purge tank, I will clean it).
8) How about a bottle of Techron in the 91-octane fuel? Don't know squat about adding alcohol, and it isn't really legitimate to do that, I think.

Yeah, there was something wrong with the stock equipment. IMHO, the cat wore out. Maybe the O2 sensor, too. And maybe all you folks are right and the Mazda tech is wrong; maybe the plugs really are not "fine."

Maybe, eventually, I'll find the magic combination.

I do appreciate your replies.

---- Bill

Boy, this will be interesting when it's my time for smog renewal . I also have the Bonez main CAT, M2 downpipe, M2 SMIC, M2 Intake, and the Bosch O2 sensor. I have previously not had a problem with passing, but that was before the addition of the SMIC, Bonez main CAT, and Bosch O2 sensor. We shall see. For sure, I will have a fully warmed engine!!;)

Just in case you run out of time
 

You can send your payment in without the proof of insurance and proof of smog. As long as you pay your renewal fees, you can "not" be cited (no ticket). That does not mean you can't get pulled over because you don't get the stickers. It just means when the Chipy runs your plates it will show you have paid and he can not cite you a ticket for over due registration.

having a high number on the HC means u have some leftover hydrocarons wich is your unburnt fuel, your car is runnig too rich, get new plugs if u already havent and check your air filter. :) goodluck

It seems like your car should pass, but definitely clear up the catch can or block it off. One easy way to see if you car will pass without going to a test only center is to get a pre test. Lots have said to have the car fully warmed up and i repeat it should be really really hot, agressive driving helps. A bottle of Redline fuel injection cleaner wont hurt neither, just make sure that stuff is gone when you test you car. Have the tech probe your car at idle, if it doesnt pass, have him rev the car and wat the readings, if slowly gets better then it should be fine. I really think its jsut that the car is not hot enough. If you car idles smoothly thats a good sign also. The reason that you were selected to go to a test only center is because its random, i think 30% of the people have to go to test only centers, thats why they have so many in So Cal, we only have like 5 in San Francisco. My cousin owns one somewhere close to Disney Land and thats what he told me. They are thinking about having that test only shit up in San Francisco but i hope it doesnt happen. And make sure when you do the real test that all you accessories are off, even the dome light and that the tech doesnt go into boost.

I too am having problems with MA dyno emissions tests. I failed with stock cat and dp with a PFC. I then bought a used 1K mile bonez (looked like new) and failed again. I then got someone that owns a four gas analyzer (he helped set up MA emissions program) to tune my PFC w/datalogit in the map regions the test uses. He had to do this with no cats since the probes would be affected by them. I got the car back, put the bonez back on and it still failed! I then called Tri-Point and talked to someone about my high HC numbers. He said that since my CO2 levels where so high it appeared my cat was not working. I have verified my airpump is getting air to the cat. I have been told that my bonez cat is probably carboned up from being used with a rich running ECU.

I just got a new TriPoint cat and will try again once I get time with new plugs (again), oil and a very hot car.
I do agree that the Bonez is puny and wonder if it is even a three way. The TriPoint cat is much larger than the bonez, almost as large as the stock cat but much lighter, claimed to be freer flowing and is much cheaper than an OEM.

If this doesn't work I may just turn the &@#% car into a trailer queen...

grampa et al,

Since my last post I realized that the "check valve (split air)" is part of the original cat and when the Bonez is installed, the valve is lost. So since my O2 readings were 0.0%, I cut the valve off the old stock cat and checked it to see it was working (it was), then I spliced it into the secondary air pipe into the Bonez and had my car retested. Sure enough, the O2 came up to 0.6%, but the HC was unaffected!! Which means to me that the O2 injection into the Bonez cat bypassed the conversion process and just went flying out the tailpipe. I don't know what the Bonez cat looks like regarding air injection, but I expected the HCs to go down with more air available.

Last night I installed new spark plugs (against the Irvine Mazda tech's advice, but I need to know). The old plugs with 16K miles on them all looked the same... shades of tan on about half the ground land with the other half black with carbon. This morning I will have the car tested once again. This is the last test with the Bonez cat. If it fails, I am buying a new stock cat but leaving the Bonez DP installed.

Full power is back; I had failed to tighten one of the large hose clamps at the output of the "air pipe/air control valve..." duh. (The Irvine tech found that.)

---- Bill

I wish I could get mine retested with the Bonez replaced by the new Tri-Point cat before you do this. The Mazda main cat is $$$. The Tri-Point is ~$450.00, they even have a high flow precat listed but were out of stock the last I called.
I do plan to get the test done late next week with the Tri-Point (if I get time).

grampa,

How do I get hold of Tri-Point? Thanks!

---- Bill

http://www.tripointengineering.com/

Good luck

SH*T I am so pissed at myself for not reading this post earlier. I went to smog my car today at a Test only station today. The first one I went to made me wait 2 hours because he was busy then tell me his machine can't pick up the rpm's in a rotary so he sent me to another place up the street. Well I wait another 1 1/2 hours and I don't pass. I wanted to run the car when it was hot but I only live like a mile from the test station so I guess I never got the cat hot enought. Also I have 3/4 full tank of PREMIXED gas, which I know found out is a bad thing to have when smoging a car. Can the heat do anything also in affecting the outcome of a smog test. 'Cuse it got up to 103 today where I live at and I they tested it a like 1:30pm.
Well heres my emissions test results.

co2 O2 HC CO NO
test rpm max meas Max meas
15 mph 2918 14 0.2 88 34 .52 .49 161 Pass

25 mph 2957 14 0.0 53 60* .50 .86* 119 FAIL

As you can see I barely passed the 15 mph test, but failed the 25 mph misserably. Do you guys think it is my cat. I am going to change the plugs, I am due for and oil change, check the air filter, change the fuel filter(have it just havent' put in on), and I have to wait till I waste all that premixed gas in the tank.
One more thing, how much denatured alcohol due u mix the gas with?

Sorry that the numbers are all moved around, I posted it right but I guess the got all mixed up.

grampa,

Thanks for the link!

kundo,

Is your car stock? I just returned from my fourth failed test, HC still bad at 25 mph (94 ppm). My car failed stock not on HC but CO (.61%), so I bought a Bonez DP and converter, and new O2 sensor. Installed and retested. Stock, my HC was 49 (passed), but with the new converter/DP/O2 sensor, HC went UP to 83. However, CO came down to 0.18, and NO readings also dropped a lot. Since that retest I refitted the check valve from the old stock cat (Bonez doesn't have one) and changed plugs. Retested again. CO and NO still better (passed with more margin) but HC up again at 25 mph to 94 ppm. Irvine Mazda tech says the Bonez cat is too small. Since reinstalling the check valve, I noticed O2 went up from 0.0% to 0.6%. Well, the secondary air is flowing better into the Bonez cat, OK, but it should be burning off the HC and instead is just flowing out the tailpipe.

My wife has had enough of this fooling around (it's her car), so we ordered a new cat converter from Mazda today ($1281 with gaskets and tax). I am going to leave the Bonez DP on since I want to be rid of the pre-cat, but if it fails again... no, think positive. Hopefully Ari will refund my money for the Bonez cat.

---- Bill

Please update when you pass
 

Damn, and I was upset when I burned two $250 Random Cat's on my Honda (bad distributor).:eek:

I thought Irvine Mazda was very expensive, but if they are helping you then it's worth it.

You need to make sure that is not something causing your engine to burn up the cats. I thought I had a bad Cat on my Honda but it was a bad distributor that wasn't burning the fuel and the Cat glowed red like a bbq charcoal.

I would like to see the results on the Tri-Point Cat'! My buddy has the Tri-Point pre-cat and they cost $700.00 ouch, but he has an Auto.

GoRacer,

I plan on posting whenever the car passes. BTW I made a typing error on the price of the Mazda converter; after tax it was 1382.80, not $1281.

---- Bill

a comment and a question:

comment: i think the check valve is simply a one way valve which prevents exhaust gases from backing up into the smog pump. if it is malfunctioning and preventing airflow into the cat it would be a problem on measured emissions, however, if left off, it shouldn't change measured emission. please correct me if i'm wrong on this.

question: for those of you who have used alcohol in your tank, exactly what kind and where did you get it. is it ethanol, methanol, or something else......does home depot have it (solvent)??? are the bottles of "guaranteed smog test passing stuff" that you get at pep boys alcohol, or some other stuff.

tia
fabian

FWIW, the first smog test on this car was in 1996 at 19657 miles. It failed with 550 ppm HC and 3% CO. This made the car a "gross polluter" and forced retest at a "test only" station. Car was stock, never touched by us after buying it new in Sept.'94. There was a pinched solenoid wire (open circuit) controlling air bypass valve, a vacuum hose misconnected, another vacuum hose deteriorated and leaking, and "other various leaks." Retest passed, but I have no data.

In 1998, at 38070 miles, the car passed with measured HC levels of 2 ppm @ 15 mph, and 8 ppm @ 25 mph. Interestingly enough, in 1998 the HC limits were 125 ppm @ 15 mph, and 75 ppm @ 25 mph.

In 2000, at 57431 miles, the car passed with measured HC of 6 ppm @ 15 mph and 11 ppm @ 25 mph. The requirements in 2000 were still 125/75. This means the CA requirements on max HC have tightened by 30% @ both 15 mph and 25 mph between 2000 and 2002! Is the RX-7 supposed to get better with age?

Fabian,

You are correct about what the check valve does. But the exhaust pressure in the cat is not constant; it is pulsing high with each exhaust port opening of the rotor chamber, and the peak pulses may be higher than the air pump pressure (spec'd at > 0.7 psi) although the average pressure is probably lower. So if the exhaust backs up into the clean air supply on peaks, the net volume of clean air going into the cat has to be lower if the check valve is not in place. I think my test results show that is true; before putting the check valve back in, O2 output at the tailpipe was 0.0%, and after reinstalling it, O2 went up to 0.6%. Also... would a car manufacturer put in a valve that was not needed? I don't think so!

---- Bill

$1380 for a CAT? Damn Bill your hardcore, I don't have the stomach to pay that much for a cat. Maybe you could try Brian at Mazdaformance.com , He give's excellent prices on OEM parts. Sorry your having so many smog issues, I can't think of anything else to recommend to you. Good luck with your new cat, and let us know the results.

eric

wstrohm
Yeah my car is fully stock right now. I bought a Downpipe yesterday and in my haste I went to smog the car today and I never checked it or thought about it not passing smog. I wanted to put my DP tommorow but since I didn't pass now I have to give the car a good tune up and see what happens. The good part is my tags don't expire till late October.

kundo,

I don't know how much you want to fool around getting to be an expert about what affects emissions, but if I were starting over with my stock system that just failed, the first thing I would do (given that my car was on its original O2 sensor at 72K miles) is install a new O2 sensor and change the plugs. I would then take the car to a certified smog test/repair station, and get a pretest. If it failed, I would leave the car, and have them tell me what needed to be replaced. They have the dyno, which I don't. There are so many things that play into the tailpipe emissions, anything else is an expensive DIY project, as I have found out. Replacing the pre-cat with a DP will not help emissions, but I have been told it will not hurt emissions if the car is fully warmed up. I would suggest using Thermotec insulation on the DP to prevent much cooling of the exhaust gas entering the converter.

My next report here will be after I have the Bonez DP mated with a new stock Mazda cat.

---- Bill

wstrohm,

Please cancel thad order with Mazda ASAP.
Don't waste money that way.

I can let you borrow my stock cat.
I just passed emissions with flying colors.

I have:
M2 Exhaust, DP, Greddy SMIC, M2 Intake and M2 ECU.

All were installed at the time of the test.
Therefore, you know my Stock Cat is good.
I can send you a copy of my test results as proof.

Since you were previously happy with your stock cat just put it back on after the test and make me a good deal on that Bonez cat.
I was waiting untill after smog to install a High Flow cat.

Naturally, I want to keep my stock cat for future smog tests or I would just trade you for the Bonez.

If you really want a new stock cat (I don't see why) at least let me get it for you with my Mazda Comp discount.

I highly recommend you try my stock cat first since it is proven to be good.

Please PM me.
I just PM'd you as well.

Lunar7,

I understand and appreciate your offer, but I do not want to set up my car to pass smog, get the car tested, and then revert to a setup that would not pass smog. I admit I used to think that way, but no more. Maybe I'm getting old.

You have confirmed my faith that I can keep the Bonez DP and pass CA emissions with a stock cat; thanks!

If my retest with the new stock cat DOES pass, I will return the Bonez cat to Ari for a full refund. I wasn't worried that the CARB has not "approved" it as long as it works, but if it doesn't, that's a different story. I think it's false advertising to say an RX-7 will pass CA emissions with the Bonez cat, if it will not.

---- Bill