NCross

iTrader: (18)

So I tested a couple weeks ago and failed. I tested at 9.1 on co2? and 3.4 on carbon monoxide?. I'm putting question marks after them because I forgot what the exact numbers and all are.

I fixed a couple tiny possible vacuum leaks and reasealed the UIM to the LIM since it was removed a cople months back with no new gasket. I also put new injector O rings on. I also put functioning ACV solonoids on.

I go to test today and what are the results? Worse than before! 11.3 on co2? and 4.5 on carbon monoxide?. How is this possible #1 and #2 what is causing me to fail?

My first guess is the catalytic converter is dead. How could I test it to find out before taking it off for a new one? What else could cause my numbers to be 4 times over the legal limit? The car seems to drive just fine. I get about 14-15mpg city and 18-19mpg highway give or take. The exhaust seems to be blowing out plenty of hot gasious air. The catalytic converter seems to be running pretty hot. The air pump is blowing plenty of air.

Also, this car has 2 cats right? Is the pre cat required to pass emissions or would the main cat do enough?

kanuk93gt

3 cats, 2 pre-s and a main

jackhild59

iTrader: (7)

Your cat is probably dead, they only last a couple of years anyway. Regarding testing the cat, that is what the emission test just did


The answer depends; Does TN have a strict visual test? If so, you need to replace the cats just as they came from the factory.

If they do not do strict visual, you can replace the cat with a universal 3-way cat with airtube. Be sure to hook the airpump to the cat so that during the test you get plenty of air to the cat. I am not sure how the S4 emission control system does it, so before you go test, verify the airflow. If the emission system is not working correctly or is missing, you can hook the airpump directly to the cat. Just don't leave it like that or the cat will burnup.

Air+new cat=pass testing!

Good luck!

HAILERS

Warm the engine up to full hot. Idle the engine. Then pull the LARGE hose off the bottom of the ACV. Feel for air coming out that LARGE hole on the ACV. A slight leakage is ok. Now pull the BLUE elec plug off the RELIEF solenoid and feel for the air at the LARGE hole on the ACV.

The air being discharged should dramatically rise in the volume being discharged. This test MATTERS.

At idle the air being dumped overboard at that hole should be very little. The airpump air SHOULD be going instead, to the exaust ports in the engine. There it's mixed with the exaust gases coming out of the engine prior to the catalytic converter. THAT is the way it is supposed to work. IF the air is being dumped out the large hole mentioned above, then it isn't going to the exaust ports, but instead being dumped into the silencer in the right front fender where it does nobody any good.

The two solenoids on the ACV play little if any part in passing emissions. Certainly not the split air solenoid that is used only in fifth gear.

ON the other hand the catalytic converter might very well be kaput.

NCross

iTrader: (18)

the large bottom hole that the silencers and all used to be connected to has a pretty decent amount of air coming out. it makes the infamous "moo" sound when i unplug the 6' hose I have on it to quiet it down.

Does the front or back solonoid control the split air pipe? my front one melted a while back and I've been driving without one until the other day. Could it have self destructed the cat?

Also, the bottom hole on the ACV puts out a lot of air when you rev the engine up. Is it supposed to?

classicauto

iTrader: (3)

Can't offer you much info, but I will offer this. Any cat over a year old has caused issues with E-test's for me. I have always had to pass with a new cat every year.....until my car became exempt that is.

kleetuz

iTrader: (2)

denatured alcohol

HAILERS

The ACV is controlled by those two vacuum hose just above it, on your 86 n/a.

Rev to 3800 and air SHOULD come out the large hole on the bottom of the ACV.

Neither solenoid per se controls the ACV during an emissions test. It's the two vacuum hose above the ACV. One goes to the Relief solnenoid (blue plug) and the other to the Swtiching solenoid (grey plug).

Both those solenoids are controlled by the TPS setting/output (on the whole, although the pressure sensor seems to have some input also).

The split air is controlled by the Switching Solenoid and the split air solenoid (on the ACV). The split air solenoid only works when in fifth gear. The Switching solenoid also sends air to the split air pipe and it all depends on where the TPS/throttle pedal is at a given time when driving as to when.

Lot of leakage from the bottom hole on the ACV??/ At idle? I've thought "what if I were to plug the HOSE coming off the ACV with and orifice or something? Maybe a round wooden plug with a small hole in the middle?". Then the air would not be dumped overboard into the fender but go where it should THE EXAUST PORTS via the checkvalve on the ACV.

But I've never had to do that, so it's rhetorical.

A catalytic converter should last a number of years, not one year IF the ACV is working. IF the ACV is not working right and you put a new converter on the car, you'll get a rotten egg smell much stronger than normal, out the exaust.

Idle your car fully warmed up. PUll one of the two vacuum lines above the ACV one at a time and see which one has a vacuum on it. The one with a vacuum is coming from the Relief solenoid........the one with no vacuum is from the Switching solenoid. As to which goes in front of the other...........don't remember right now, maybe later. Gotta go.

NCross

iTrader: (18)

thanks for the info. i appreciate it. the vacuum lines could very well be crossed since Ive had the UIM off twice.

j9fd3s

iTrader: (3)

yep hailers is right. ive been smogging these things for 15years now... good acv and air pump is more important than a good cat....

might wanna think about the o2 sensor too

R3N5LOW

iTrader: (1)

when are you going in for another test?

HAILERS

Simple way to find out. You have to fully heat the engine up first. Then idle the engine. Now pull that LARGE hose off the bottom of the ACV. Then reach over to the other side of the engine and pull the BLUE plug off the Relief solenoid. When you do that, a large amount of air should now come out the large hole at the bottom of the ACV. Large compared to what it was prior to pulling the Blue plug off.

Actually, now that I think of it, yours is probably on right, because you said you rev'd the engine and THEN a lot of air came out the LARGE hole at the bottom of the ACV. That means that when you got over 3800 rpm, the ECU killed the gnd signal to the Relief solenoid which in turn means the vacuum stopped going into the Relief diaphram inside the ACV, which in turn let the air from the airpump go overboard out that LARGE hole at the bottom of the ACV.

After fifteen plus years the diapharms inside the ACV get hard. Especially on a turboii because of the heat from the turbo.

There are ways to cheat the system. One was what I suggested about putting a *stopper* in that large hose at the bottom of the ACV to force the air to go to the exaust ports/split air pipe.

Another that would help a little, is to remove the Port and Split air solenoiods on the ACV and remove the poppet valves and springs. Then reinstall the solenoids back on the ACV. That act would feed more air to the exaust ports and the split air pipe. A little more air.

But think. If a stopper or something similar was put in the hose on the large hole at the bottom of the ACV, then the airpump air would have to go where I said. I'm really against fudging like that.............but. And I'm also not sure how that would work on passing emissions. In Tx we seem a little lack on visuals but do, do a rolling emissions test at two different speeds.

I'm sure that if you have a catalytic converter with years of use on it, that if you replaced it, all would work as original, and you'd pass

HAILERS

The working of the Relief and Switching solenoids is interesting in a way.

I put two LED lights on the relief and switching electrical plugs and ran the wire and lights to the wiper arm. Then watched the lights when driving.

GREEN LED on the Relief and RED on the switching.

At idle just the GEEEN comes on. Means the air is not being dumped overboard and is going to the exaust ports.

Drive at a steady speed down the avenue and both lights are on. Red being on means air is going to the Split Air Pipe now.

Let off the throttle and we're back to GREEN only. Apply throttle and back to both being on.

Drive steady down the avenue, and about 120 seconds later just the RED is on and GREEN off. Now if GREEN is off, the airpump air MUST be going overboard.

But for some reason the RED is on. I suppose most air is being dumped overboard out the right fender silencer, but some??? is still going to the split air pipe. Got me.

That was done on a 86 non turbo. Turbo might be a little different.

And if you have the key to ON and engine not running, you can try this. Hold your hand on the Split air solenoid and have someone go into and out of fifth gear. You should be able to feel/hear the solenoid click/pull in as it's put in fifth gear, then taken out. Just showing how the Split Air Solenoid just lets extra air in when in fifth gear. Same on turbo or non turbo.

Just rambling. I believe it was j9fd3s who sold me a working turbo ACV when I found mine had a TOASTED relief diaphram. Thank you.

And SixRotors told me the *thing* about removing the poppets out of the two solenoids for extra air. Personally I can pass without doing that. Good cat.

I am a bit of a cheat though.

NCross

iTrader: (18)

im definately getting a new cat though just because i can get one for under $100 new. i figure it couldnt hurt since this one seems original. im sure it will free up a little power and MPG as well.

maybe i could do the "furniture leg cap mod". Take a small length hose, tap a furniture leg cap into it with a small hole drilled into the tip for excess air to drain from. that would pressurize the system if im thinking correctly... getting rid of the "moooo" will be a small benefit.

shogunxp

i didnt pass smog twice. then i went to a muffler shop to get my cats looked at for free. they cut away a hole on the cat just to see the inside of it..it was corroded. i got the two cats replaced on mine (1991 NA FC) a big cat and a small one. that made me pass smog.

two cats obviously thats gonna pass smog. if all else fails...

NCross

iTrader: (18)

the 02 sensor is 3 months old. i could tell a difference in performance and MPG after the install so i know its working.

NCross

iTrader: (18)

everything that has been replaced on the car in the past year (6,000ish miles)...

-cone air filter with heat shield
-fuel filter
-battery
-ACV solonoids
-o2 sensor
-near engine fuel lines
-injector O rings
-cleaned up ground points for 3800 hesitation
-new starter
-clutch cylinder
-brake cylinder
-all fluids changed at least once
-running 87 octane fuel

Stuff I've done to the car that "may" affact emissions...

-TB "mod"
-I ran 4 ounces of premix twice about 6 months ago with a possibly functioning OMP (probably killed the cats...)
-2 1/2 inch Mazdaspeed dual Y pipe exhaust from the cat back
-A/C removed
-useless/broken options removed (AAS, rear wiper and tank, front wiper tank/lines, cold start, blower fan, lots of wiring/relays for all of this stuff).

j9fd3s

iTrader: (3)

as long as the acv is putting the air pump air into the EXHAUST ports it should pass out the tailpipe