I'm starting to wonder if the exaust gasket was put on *** backwards preventing the port air from mixing. There is a half inch hole in the gasket that is supposed to match a similar hole in the rear housing. If the gasket was put on *** backward , the half inch hole in the gasket would be fwd instead of aft. The port air could not get out to the manifold. Hmmmmmmmmmm.

 

So what you are generally saying is, that you have eliminated the injectors as probable cause? And that comment about the exhaust gasket has me wondering too....There has to be some explanation as to why the O2 readings are high, since we are all in agreement that .001 is generally the accepted norm at idle. You say your 87 N/a (which is what I have) reads approx .003 at idle. My thinking also is that the mixture probably ISNT rich. Everything I have read seems to indicate that this is norm for these cars. What I think is that there is something really wrong with my secondary air system. My readings on O2 are low at startup (.40-.45) then steadily creep to .5-.55. But the numbers on at the emissions station dont lie, there is something REALLY wrong here. How are you checking your injectors? I read on one of your threads that you were basically applying voltage to them for 60 secs, with fuel pressure applied, into a graduated cylinder. You also stated that you were getting mixed results. I am not particularly interested in purchasing new ones, but I think it would be a smart move to at least do some type testing before I go shoving them back in. I could put pressure to them to see if they leak I guess....

The sulphur smell with your wifes car is more then likely the cat. Thats a normal smell associated with that device.

Rat

 

HAILERS- A word about the car with the sulphur-smelling cat.
Yes- it means the cat is working- but it is working very hard!!
Usually, a car will only make that smell when it's being floored (ever been behind a new car with a cat behing floored? stinks like eggs..)
It shouldn't be working that hard- it means the car is running rich- or experiencing poor combustion.
You CAN burn the cat out, especially by overheating it if it's working that hard all the time.
So, point: In normal driving you shouldn't smell that at all, unless the cat is really working hard to clean up an overly rich mixture.

 

Didnt think about that....You got a point there Bambam7. And his O2 readings on that car are as bad as mine...Doesnt this suck.....

 

Well thank you BAMBAM. For right now I'm going for the exaust gasket route. The acv is first rate, the airpump is a pumping good and I know that any normal car with acv, airpump etc should read a very low voltage at idle at the o2 sensor. The only time it won't read a low 02 senor voltage and will read high, is if there is no PORT AIR going from the acv, thru the passages in the housings, and exiting the half inch hole at the rear exaust port. A condition that would cause that would be a broken belt on the airpump, a busted switching diaphram in the acv, or no vacuum going to the two nipples at the top of the acv. None of those conditions exist on my car. The only light I seee at the end of the tunnel is if the exaust gasket got turned around 180 degrees. Then the half inch hole at the rear exaust port would be blocked preventing the airpump air from mixing with the exaust gasses. I KNOW my 02 sensor is good because when I step on the throttle and then lift off, the aav in the acv is opening and feeding fresh air into the intake manifold causing the 02 sensor to read .0003 etc. Now who put that exaust gasket on. The same person who if you gave him a steel marble, would break it in a heartbeat. me.
I changed the primary injectors with two others and the 02 reading is the same. This car runs darn good for a stock n/a. No hesitation or any of that other bs. Idles like a charm. variable resistor a touch below the half way mark.

 

J-RAT, sorry, I wrote the above post prior to reading yours. Before you do the injectors, take the nuts off the exaust manifold and pull the exaust header out just far enough to see if it is out 180. Go to MAZDATRIX SITE at http://mazdatrix.com/e6.htm and look at item E. See the hole just below the exaust port on the left???? That should be located at the rear exaust port. The injector for 60 sec. Yes I had a small learning curve there. I was letting the battery discharge while fiddeling aroung which gave me odd volumes for the injectors. Got my act together and kept the batt topped off and the volumes were correct. I also proved to my satisfaction that I have no leaking injectors. Trust me. Look at the gasket prior to messing around with the injectors. Just an aside. I read the RC ENGENEERING site and how they test injectors. They emmerse them in a ultrasonic bath while pulsing them. How cool. Just shows if you put the whole injector in some cleaner your most likely not going to harm them.

 

Problem is, I lack certain items that you have in order to complete the test. Should I send them to RC Engeneering?

 

Yeah. Send them to RC. At 25.00 a pop its a good price. Can't do anything but help. But I can't help but feel the problem lies else where. Weather is going to be rotten here for the next two days so I'm not going to be able to check the exaust gasket out for a few days. I think when and if I ever get home tonite, I'm going to take the 87 that passed emmisions with flying colors a couple of weeks ago, and remove the switching and relief vac hoses from the acv and compare the 02 voltage before and after. Maybe even take the belt off the airpump. By the way, the TurboII 02 reading at idle is in the .8 range. I fully expected that because I still have not fixed the baked switching diaphram. In other words the port air does not happen on that car because the switching valves diaphram is kaput. That car passed emissions about six months or less ago. That condition existed then.
I just remembered what Six Rotors suggested a few posts ago. Because the switching diaphram is busted on that car, all the air went to the split air and in the cat.

 

Hey J-RAT, read this old thread https://www.rx7club.com/forum/showth...threadid=13266 That is where I discovered the idle reading was high without the acv. At first I thought it was the aav that caused the low reading then was wised up that it was the switching valve in the acv. Also notice the .8 reading with the acv blocked off. The only problem that I have on the wifes 86 is the airpump air isn't making its way out of the housing passages into the exaust stream. Gasket. Gotta be the gasket *** backward.

 

I'm getting .798v at idle with airpump removed and blocked off. The car smells REALLY rich. Just put a new O2 sensor in, I'll eventually get around to pulling off the cat. I'm assuming that my car smells rich because of the fact that I STUFFED MY DUMBASS, BROKEN HAND INTO MY AFM in an attempt to "richen" the mix and just spun the wheel WAY OFF stock. I've been able to get the car to run nicely, just rich. I'll pick another AFM and check the voltage at the ECU with that one.

B

 

WHat on earth?!?!? How do you change the AFM setting? I havent see that ANYWHERE!!!

Rat

 

Well HAILERS, I got the top half of the motor already off, so I assume that getting to the exhaust isnt too much more hassle..However we are having rain here too, so I am gonna hibernate inside tonight. I plan to take that apart sometime this week. What is good to know is that now we have somewhat of a baseline to work with and there is NO DOUBT that I have a problem. Good possibility that its the same one you have. But I might send the injectors in anyways. Would it be cheaper to just hook them up to the secondary fuel rail and hit them with pressure? Probably not, cause that takes the pressure regulator out of the picture...Hmmm. Okay, maybe I will just mail them out..

Rat

 

JRAT—Let me start by saying, "DON'T DO IT!" Now that you've been warned, crack the seal around the black on the AFM (This only applies to 86-88 cars), and turn the toothed wheel two-three teeth counterclockwise(?). If you do it, make sure your MARK THE ORIGINAL POSITION. I had read that it tricks the ECU into thinking it needs more fuel relative the amount of intake air. I can see how it would work, but I think that "mod" and a catalytic converter with no air pump has made ny garage a very dangerous place to be.

I think my ECU is shot. I'm not getting a reading off the back of the plugs now (2D). And since I started recording all of my pin-out voltages the O2 pinout has decided to stop giving me a reading. I just put the new O2 sensor in yesterday—I get a reading of .78 off the O2 sensor direclty but when I get to the ECU it gives me nothing. I even ran another wire from the O2 sensor to the ECU to see. On the new wire I get .78, when I stick that puppy into the ECU connector (at 2D) I get a -000 reading. I have a feeling I shorted out the O2 circuit(?) on the ECU. Ho Hum.

I guess my next step will be to crack the ECU and track down the O2 connection point and see if I knocked the solder connection off. These damned things are soooo finecky! I've already resoldered EVERY joint in every computer in the car.

B

 

/\

 

I just got home and pulled the vacuum hose off the front nipple of the 87 car, (switching valve vac input) and the voltage at idle for the 02 sensor went from .000 to .8v. So it is indeed a normal reading for the 02 IF the acv is disabled or the air pump is off.
OUR problem is why with all hooked up and functional does it read the .8 and we are on our way to final victory if it will stop being cold and rainy. Also I have a bad case of sleep deprevation right now. I don't think theres a thing wrong with your injectors. If the car is going to be down for a few days and you have the spare change, you might just go ahead and send them out. I think they have a quick turnaround. Later. Gasket, yeah!

 

HAILERS— If you're getting .8v on 2D at idle would that not give you an O2 sensor error code? I have no ACV nor Air Pump, so is it safe to assume that I will now always get an O2 Sensor error message? Hmmm. The split air supplies o2 AFTER the sensor though...I'm lost.

Brian

 

RXSE7.....there's more to the acv than split air. Yes split air is after the o2sensor. Its the PORT AIR and the air from the AAV that come before the 02 sensor. If you've had a acv off the car, you saw that check valve that is about the size of a half dollar. That is the path of the PORT AIR. It goes into that check valve and hole and goes thru passages in the rotor housings. It exits just under the rear exaust port thru a half inch size hole, into the exaust stream. Before the 02 sensor.
At idle the switching valve and the relief valve in the acv have a vacuum on them. The relief valve stops the airpump air from being dumped overboard thru the silencer in the fender. The switching valve shuttles and sends all the airpump air thru the check valve and the path described. There is no split air being delivered at the idle.
When you step on the gas, the switching solenoid cuts the vacuum off the acv and the switching valve internal to the acv, which in turn allows air to go to the split air passage to the catalytic converter.
The misconception is that the airpump and acv's only purpose is to send air to the cat thru the split air pipe. You've got split air, port air, and the aav.
So you see now why a bum acv, or the lack of, will cause a high 02 reading. The .8 or so is normal for a bum system. A reading of .003 or minus whatever is normal for a fully working system. The above is for a 86-88 model. Other models I can not vouch for.

 

Oh! I done did forget about the 02 codes. No. I have one of those invaluable led displays that you can make to interrogate failure codes. The 02 signal is not in the loop at idle, as you know and the pig is functioning. From what little I have read, a 02 sensor cannot be trusted out of the stoich range. I saw a graph on this site, where the same fuel mixture was exposed to a 02 sensor at different temperatures. It had three different voltage readings for that same fuel mixture. I have no faith whatsoever in a 02 sensor above and below stoich. Buy a wide band. They don't cost that much.
I've done a lot of done diddin today. Sleep. Gotta sleep. Must not forget to sleep today.

 

Go to bed.

Oh God! I just heard Led Zeppelin in a Cadillac commercial.

 

CORRECTION FOR THE PATH OF THE AIR FROM THE ACV; The air does indeed exit prior to the 02 sensor, but not thru the half inch hole. It exits from around the periphery of the metal insert that is mounted inside the exaust port. Thanks to Six Rotors for giving me the heads up on that. So it cannot be the gasket blocking the half inch hole. But it is very apparent as to why the air from the acv is not getting to the periphery around the insert in the exaust ports. I will never tell, but if someone makes a correct guess I'll come clean and admit to it. Only someone who has rebuilt rotarys would know. J-Rat is going to check out if my theroy is true. I can't because I put my intake back on. We may let this post die a natural death out of embarrasment.

 

Okay HAILERS...You are gonna have to let me in on this little theory of yours. Which leads to another question. WHats the quarter sized hole for in the exhaust manifold gasket? Next question, where can I get a new check valve...The quarter sized valve behind the ACV. I checked MAZDATRIX for the valve, and they dont have it.. They do have the gasket for the ACV and I plan on getting one...Do you need one HAILERS? Might as well get some if you need them. I was gonna get the exhaust gaskets too, but until you let me in on what the big secret is, I am gonna hold off on getting them.

If anyone else knows where to get the check valve behind the ACV (no, I dont know the proper name for it) PLEASE TELL ME!!!

Rat.

 

OK. J-RAT now knows what his problem was. The rotor housings were put on wrong. The front rotor housing is in the rear and the rear in the front. Although they look physicaly the same, the air passages inside that feed from the acv, air pump air, are different. If you put the housings on in reverse order, then you block the air from reaching the exaust ports. The acv will then only work in the aav mode and the split air mode. At idle the 02 will always read way high like .8 v or so. HIS ENGINE WAS BUILT BY THE SAME PEOPLE WHO GAVE YOU THE DEFECTIVE LOGICON, DEFECTIVE WIPERS, DEFECTIVE IDIOT LITE ASSY blah, blah, blah...MAZDA At least I understand it was a rebuilt motor from MAZDA. Correct me if I'm wrong J-RAT.

 

REBUILT MY ***!!!! THIS WAS A BRAND FRIGGIN NEW ONE!!!!!!! FROM THE DEALER!! I AM SO PISSED I cant even see straight!!! UNFRIGGIN BELEIVABLE!.....I hope we are sure about this, but on the top of my front rotor housing there is an "R" plainly stamped. And in the same spot on the back rotor is an "F" . I highly doubt that MAZDA is gonna do anything about this, but I am DEFINATELY raising some hell!!!!

YIKES!!!!

May be time to learn how to rebuild, eh?

Rat

 

I'll be darn if I'm going to rebuild mine. Runs great and passes emissions. It is defective since I'm the lowly dirt bag that put the front rotor in the rear and vice versa. But for Mazda to have done so is just not right. They are professionals. The engine is technicaly defective because there is not way for the PORT AIR part of the acv to function. If you have them place a front rotor and a rear rotor in front of you with the front one to your right and rear to your left(looking at the exaust) and examine the triangular shaped hole at the mating surfaces at the bottom, aft side of the rear housing, you will see in that triangular hole two exit holes. One exit hole is exiting a half inch hole facing the exaust manifold. The other exit hole is at the top of the triangular hole and goes into the exaust port where there is a diffuser of sorts.
But if you look at the triangular hole in the front housing, at its rear, aft, mating surface, you have a triangular hole but it has only ONE exit hole. That exit hole comes out the half inch hole facing the exaust header. That hole is on no use because the gasket is in the way and even if the gasket was not there, there is no hole in the header at that point.
This is as hard as a bitch for me to explain. If you were here with the two housings in front of you it would make sense. If Mazda will not make restitution, don't rebuild. Get the cat and I think you'll pass emissions. The performance of the car isn't hurt , at least not on my car. I'd also block off the EGR valve since the passages for the port air and egr air have been basicaly swapped around. Have not really thought that part out clearly.

 

Another thought. When you go to Mazda, try not to show anger. Its going to be difficult to explain and for them to understand. If they say it makes no difference, try to explain that it does make a difference. Have them bring you two housings, one front one rear for the 86-88 years. At each exaust port, there should be TWO half inch holes. If they don't then they are not 86-88 housings. Only one of those holes is actually used. Its the forward one on the rear housing(remember the gasket?). Try to show them the triangular hole on the aft mating surface and how the rear has two exit passages and the front only one exit passage. All the difference in the world if you put the housings in the wrong place. Later.