I just failed the TN emissions test!

HC: 854 PPM (Max: 220 PPM)
CO: 7.27% (Max: 1.2%)

It seems that I am not even close. Anyway, I get 90 days to re-take it for free.... is there a cheap way to bring my HC & CO levels back to the minimum? The exhaust system is stock... the car is idling a bit high (1400 rmp). Additionally, I suspect my TPS is bad... (did the lightbulb test.... both lights off regardless of TPS position), would that have anything to do with it?

Any help would be appreciated. Thanks.

 

My money would be on fixing whatever is keeping your idle too high. Get that TPS adjusted or replaced as your first step!

 

i live in Florida so i dont do this kind of stuff but i heard somewhere to run 10-15% alcohol. and lean the fuel mix if its carb.

 

I guess you have an -SE or a 6-port swapped in.

First off, don't use test lights to adjust the TPS. A decent multimeter is only about $10, and you can use it for all the electricals in the car.

Second, drop the cats and inspect them. If they've never been replaced, they're probably clogged and useless by now.

 

I did that too... and I got very weird readings. I'll check out the parts for sale section of the forum for a used TPS... cause I don't feel like paying $120 for a brand new one.

My question is, though, would a bad TPS cause the car to fail emissions? Also, how can I visually inspect the cats?

 

i think it'll be kinda hard visually inspecting. i think (i don't have cats so i'm not sure..) if you let the car run for a while and look under at the cats, if they're glowing they might be clogged. I'm sure glad i don't have emissions here.

 

Depending on how competant the mechanics doing the test are, you can bypass the ACV and plumb the air pump directly into the cat. "The solution to pollution is dilution" This will put more air into the exhaust mix, therefore diluting it and bringing the numbers down.

Of course, this is 1)cheating, and thus an ethical dilemma and 2) a ghetto patch-job which doesn't address the real issue.

You *should* be idling around 850rpm, so if you're at 1400, there's definitely something that you should get to the bottom of.

This Page addresses GSL-SE idle problems, since I know basically nothing about non-carbed cars. It's got a heck of a lot of great info, and I found it in the FAQ

Try to address the problem, that's your best way of passing. Other things that just generally help for emissions are:

Replace your air filter, fuel filter, spark plugs, plugwires, dist cap and rotor and change your oil. Having all of these things in tune helps to make sure your engine gets the most, cleanest air, with the proper mix of clean gasoline, and a strong spark to fully burn all of that. The oil change helps a *little* because of the oil-injection system on the car. Since the OMP injects oil in with the fuel, dirty oil burns dirty. Not much of an improvement, but definitely something.

Ethanol-blended gasoline is available at some gas stations which burns cleaner, and thus lowers the emissions of your car. You should burn about a tank of this before your test, and be burning it AT the test if you can find it.

Run a bottle of fuel injector and fuel system cleaner through.

And for god's sake, find out what's making your car idle at 1400RPM. That's 500 more revolutions per minute, or 3000 more individual explosions than you should normally have. Without the load on it, that's gotta be burning dirty.

Jon

Edit: "and thus an ethical dilemma"...? Remind me never to post when I'm doing my homework for "Business Ethics and Values In The Workplace 101".

 

Thanks Jon.

I have been looking at the GSLSE idle page for quite a while now... the very first thing I did was test the TPS, so I hooked up the multi meters and got no reading, so turned the screw clockwise for about 10 turns, until I got some weird readings, but nothing steady... so I kinda just left it there. Before then, the idle was surgin between 800 & 1100 rpms... but now it idles steady at 800 until I rev it up... then it just hangs at 1400.

I also tried cleaning the BACV valve... i pretty much had to yank it out cause the gasket was dead stiff... and it broke (need to get a new one). But I couldn't separate the BAC from the Air supply valve, also because of the stiffness of the gasket between them. I tried pulling real hard, but no luck. So at this point I put just a little carb cleaner from where I could, and put it back together, with the broken gasket. Nothing changed in the idle speed though. Anybody had this kind of trouble trying to clean the BAC valve?

 

You're on the right track to do the following (and for the reasons specified). This is my Top 10 to Pass Emissions Testing:

1) Reduce idle speed - the idle test is performed with the engine at whatever idle you set it at. If it's running at 1400, it should be 800, and your emissions at idle will be too high - check to see which part of the test you're failing, and then focus there. Adjust idle speed by the air adjust screw on the TB, and also the TPS makes a BIG difference in idle air/fuel mix - adjust with 2 lamps method and you're be dead on.

2) Adjust idle mixture - There is a variable rheostat on the passenger strut tower which can be adjusted to Rich/Lean the idle mix. If your idle 'hunts', it's lean. Lean it out as much as you can go without negatively impacting idle speed or 'quality'. A lean idle mix will help you pass this part of the test.

3) Cap/Rotor/Plugs, wires if needed - Hot spark = complete combustion. Cheap investment in parts to pass inspection. If nothing else, clean your plugs up thoroughly so that they will spark cleanly. Fouled plugs will toast your test results.

4) Check Cats - If your cats glow red at night, that means they're working, but also indicates that your mixture is too rich, or you're running excessively high octane fuel (see below). Cats work fine on my 84, so your should be alright too unless they're rusted through, or you have an exhaust leak somewhere.

5) Check Airpump - the AP pushes fresh air into EITHER the exhaust ports to mix in the manifold, OR the primary cat to fuel the platinum brick. If the AP can't push the air where it belongs, your car won't pass emissions. Remove the ACV on the side of the lower intake manifold and clean it out, thoroughly.

6) Run 87 octane, ONLY - high octane fuel should be reserved for high-output piston engines with VVT and other tricks. It is not needed in your short combustion cycle rotary engine. Octane RETARDS fuel ignition - you want fast ignition to burn all the fuel in the engine, not in the exhaust, or in the atmosphere. Fill up with 87 or the lowest you can get before your next test.

7) Increase rear tire pressure - The driving part of the test requires your rear tires to turn the dyno. Increase rear tire pressure to create less rolling resistance, which results in less fuel needing to be burned to overcome this resistance. Bump it up to 35-38 psi for the test (on good tires, ONLY), and then drop it down after you pass.

8) Change/remove Aircleaner - Getting fresh air into the engine will allow for more complete combustion. If you're running rich, it could be that the engine can't get enough air past the air filter. Remove your airfilter if you think it's the culprit, if only for the test. Be sure to put it back on afterward!

9) Clean/replace fuel injector(s) - a dirty spray pattern and/or an inoperative injector can usually lead to lean mixtures, but could be stuck open causing a lot of fuel to flow when it shouldn't (at idle). Last ditch effort, replace injectors and try again.

10) Freeway driving 15 min prior to test - Heats up the cats so they're up to operating temperature, and keeps the exhaust system hot to help burn whatever fuel comes out of the engine that isn't. Also, turn off all electrical accessories and A/C while you're waiting, these result in increased engine rpm and will 'load-up' the engine right before the test - which can lead to a fail.

My 84SE has never had a problem passing emissions - note that I swap out my RB exhaust for stock every April,... Yours shouldn't have that much of a problem if it's in good running condition. Good luck, and report back,

 

Don't touch the TPS unless the car is warmed up fully and is running at the proper idle speed!

 

True... but thats why Mazda engineers put an ACV there in the first place, or plumbing air directly to the cats would be sooooo much cheaper.

The dilution process actually begins with the ACV allowing air, pumped by the air pump of course, through the intake manifold and into rotor housings, exiting directly into the exhaust ports, thus the emissions are diluted right there inside the exhaust manifold before even hitting the cats... additional air is bypassed by the ACV and sent to the cats as well.

So.... if youve done everything that LongDuck has suggested and everything else is in good working order (ACV good, catalytic converters good, new plugs, etc...) and your car STILL fails emissions testing... the air ports within the rotor housings are likely to be clogged up, especially in an older original engine... your car isnt getting enough air for emissions precombustion.

To fix it will require removal of the entire intake and exhaust manifold.

Block the exhaust ports with paper, a rag, etc...
The air port is the rectagular shaped hole located directly below the center intake ports (on series4 13Bs they are on the side housings)

Use a coat hangar wire and a pipe cleaner brush and jam it down in there.. Yeah thats right! Ram all the crud and carbon down and loosen it up.

Next would be to use compressed air to blast out all that crap.... it will shoot out of each of those 1/2" holes in the exhaust ports (ever wonder what those were there for when you installed that header?)... this is why you must block them off to keep all the crud from reentering the engine, and keep your eyes away from it!

Repeat this process until you believe that the air passage is freed up from emissions emphysema
A good time to do the ATF treatment before reassembling.