driftxsequence

iTrader: (8)

Is there anything that i need to do to make the air pump run properly without the other emissions equipment? The previous owner had all of the stuff removed and i need it put back on to pass inspection now..

nycgps

iTrader: (4)

I would say no.

driftxsequence

iTrader: (8)

i thought that it had some different speeds it ran at according to engine RPM, such as it was used less at higher RPM or it would burn up the cat.

nycgps

iTrader: (4)

I could be wrong but

if its as simple as that, Mazda don't have to put "the whole rat nest" on top of the engine ...

So I still gonna say no.

Bamato

iTrader: (6)

I think that since the air pump runs directly off an engine pulley, it's output is already relative to the engine RPM's.

rx-7 obsessed

if there is a belt on it and the pipes that run to verious places are still conected it will pump air.

Scrims

iTrader: (2)

I think understand what you're getting at. The Air Control Valve (ACV) controls where air is directed at certain rpms. Under ~2000 rpm or so air is directed to the cat to help its reaction to clean up the air. At high rpm the air is redirected out the air silencer.

So to direct air properly you need the proper ACV for your car. Whether that alone will get you to pass emissions I have no idea.

driftxsequence

iTrader: (8)

anyone else?

arghx

iTrader: (3)

You need the ACV if you use the factory smog pump. You can use a GM electric smog pump.

Technically, if you hook up the airpump to the ACV with the split air pipe and no vacuum lines, air should flow to the cat continuously. I haven't tried this personally (we have no tailpipe tests here) but I have studied the secondary air system extensively on both the FC and FD.
I'm going to assume you have an s4 n/a but the basic principles still apply to other models.



If you look carefully through the diagrams you can see that without any vacuum lines hooked up:

1) the switching valve is spring-loaded such that air flows out to the split air pipe (to the cat)

2) the relief valve is spring-loaded closed so that air will not be vented back to the airbox

3) the anti afterburn valve isn't even controlled by a solenoid. It's most likely opened when manifold vacuum is extremely high (which occurs on deceleration)


So if it were me, I would only hook up the air pump, split air pipe, the ACV, and the main airpump hose. You should then have secondary air flowing to the cat continuously. Here is a list of all the exclusively emissions solenoids on an s4 n/a (none of which you will need):

1) switching solenoid: cuts vacuum to the switching actuator on the ACV, so that airpump air will flow out to the exhaust ports instead of to the cat

2) relief solenoid: applies vacuum to the relief valve on the ACV so that air pump air is not used, and instead dumped out to the silencer.

3) EGR solenoid: applies vacuum to the EGR valve so that exhaust gases from the exhaust port will flow into the intake manifold. EGR isn't really needed on a rotary to pass emissions. S5 and JDM cars didn't even have EGR valves.

4) AWS solenoid: accelerated warmup system allows extra metered air to flow into the engine past the throttle plates. This revs the engine up on cold start. The AWS system is only on USDM-compliant cars and isn't needed to pass an emissions test

driftxsequence

iTrader: (8)

Thank you very much for the detailed explanation.

I will try to make sense of this by taking it out to the car and putting words to parts to see how this is going to work. i was hoping i could just hook up the pump and ride 10 minutes to the dmv, get it to pass and pop back but it looks like it'll be a little more complicated than that

i really appreciate you taking the time to do that!

arghx

iTrader: (3)

Ok, here's option 2.

Hook up the ACV. leave the split air off completely. Run a vacuum line directly to the switching actuator on the ACV. Air pump air should now continuously flow to the exhaust ports and dilute the mixture before it reaches the cat. You might need a check valve to help hold the vacuum there, just because this is sort of a ghetto rig. I'm not entirely sure.

There are only 3 places the secondary air can go to.

1) the cat, through the ACV and out split air pipe
2) the exhaust ports, through the port air passageway in the ACV and intake manifold
3) dumped out back to the air cleaner.

The switching actuator is just a spring loaded valve with a diaphragm to control it. In its normal position (no vacuum on the diaphragm), it is configured so that air will flow to the cat through the split air pipe. With vacuum applied to the switching actuator the air flows right to the exhaust ports. With vacuum applied to the relief valve the secondary air is dumped back to the air cleaner.

SO... knowing this, we can use engine vacuum (or a lack thereof) to direct the flow of secondary air. The factory solenoids do just that. The switching solenoid will cut the vacuum to the switching actuator so that air will flow to the exhaust ports. The relief solenoid will apply vacuum to the relief valve so that air is dumped back out to the silencer. If you think about it, it's really not that complicated. Vacuum or a lack of vacuum, that's all it takes to control secondary air.

FYI the FD ACV works like this too but it's a little more complicated because the air pump has an electromagnetic clutch to reduce drag on the engine. There are also a couple additional solenoids on the actual FD ACV itself.

arghx

iTrader: (3)

I modified some of Mazda's FD ACV diagrams to show how the 3 main operations work on the FC ACV:



In the top diagram secondary air is flowing to the exhaust ports. Vacuum is applied to the switching actuator (the switching solenoid itself is OFF). In the middle diagram, no vacuum is applied to any actuator and air is flowing to the cat out the split air pipe. In the bottom diagram, vacuum is applied to the relief valve only (relief solenoid itself is ON) and air pump air dumps back out to the air cleaner. For an emissions test I don't think you would need the air relief function at all.

I will say though that I'm not sure if running the secondary air to the exhaust ports continuously will help or hurt your chances of passing the test compared to directing the secondary air to the cat. It may not have a major effect at all.

j9fd3s

iTrader: (3)

we do have testing in CA. the port air DOES have a major effect on emissions. the simplest way to pass smog, is to give the thing port air. in ca the car will NOT PASS without port air, period, but give it port air, and so far every EFI rotary passes with no problem.

the FD chart is probably close the the FC chart, but its labeling could be better. once its warmed up the port air is used until about 2500 rpms (its throttle based, so the rpm varies), which IS the emissions test. you can literally leave the split air pipe at home with no effect on the emissions test

as a contrast the split air passage has a restrictor (4mm?) and it goes to the rear half of the cat. PORT AIR does not have the restrictor, and all of its air goes before the cat.

i've smogged ALL of the rx7's ive ever had, every other year since 1993....

markusparkus

iTrader: (1)

so, if you were to remove the restrictor in the split air pipe and run the air pump directly to the pipe, you should be able to pass emissions fine, is what I'm hearing.

I have heard that running without split and port air will ruin your cat. I don't know why that would be. Any truth to that? Is there a benefit of running port air as well? I'm curious why they went to the trouble of doing both port and split air to the cat.

j9fd3s

iTrader: (3)

no, just hook it up to port air. if you're lazy, the port air passage in the intake is round, hose barbs are round, put air pump right to that. in CA we just stick a couple of bolts in the ACV so its physically locked into port air if its bad, the default position of the valve is to dump to the air cleaner.

to the second running without port or split air will ruin the cats. although running with port air all the time is bad too, the cat gets HOT.

the reason the air pump is needed in the first place is that the cat needs to see a 14.7:1 air fuel mixture to work. due to the physical layout of the pre rx8 rotary, this cannot be done without misfires. a misfire = a whole chamber full of unburned HC's go out the tail pipe = high HC emissions.

so mazda's (and just about every other car company at some point) was to run the engine rich enough not to misfire, and then just add air to the exhaust with the air pump.

the rx8 engine is able to run @14.7:1 so it only has the air pump for cold starts, again like every other car. the rx8 air pump goes right to the exhaust manifolds inlet, very close to the older engines, and like every other piston engine

its simple, it works.

markusparkus

iTrader: (1)

I see. Well, I have no ACV right now, so I'm going to have to get out the FSM to find the port air passage you are referring to. Sounds like the ACV is useful to save your cats, if you have them. I was planning on just running the air pump to the split air pipe for the smog test and leave it like that. It sounds like I'll burn out the cat doing that though: the first half because of not enough air and the second half because of too much.

Might there be a way to run port air, but bleed off some of the output from the airpump to reduce the flow to the cat?

Do you put in your cats and air pump for smog test and then remove them afterwards?

tweaked

iTrader: (4)

I don't have any pics, but I removed all of my emissions too and have a RB header. But still have to pass a sniffer test.
I left my stock air pump and bought a new hose to go from the pump out put to the air tube directly. then scrounged for bent hose from pump intake to air filter box hole.
but I have an S4 so I needed my aux ports too. from the nipple on the smog pipe, I installed a plastic vacuum coupler thingy I found @ Autozone. It's white and big in the middle. I connected this inline between the smog pipe nipple and the aux port nipple. Then I took the smallest drill bit I could find and drilled a hole to bleed off pressure. It was too much pressure still and the aux ports were open @ idle. so i added another, then enlarged one or both in very small increments until I got close enough to 3800 rpm opening. They are still a little early open, but I intend to one day get it perfect.
I know they are probably opening earlier than that when under load. But it works well enough. My take off torque is better than open ports.

arghx

iTrader: (3)

Is this a turbo or n/a engine?

j9fd3s

iTrader: (3)

the port air passage is the big round one on the intake manifold under the acv/acv cover plate.

my current car is stock, i just made sure the ACV was good (port air) before i smogged it.

i have done cars that were rigged up just to pass and the emissions stuff came off right after. people have been doing that here probably since the first smog test....

since i have the stuff lying around, i've always rigged up an ACV to go to port air, put the air pump and cat on, go smog, and then come home and take it all off.

tweaked

iTrader: (4)

I just happened to go get my car sniffed today.
This is an 86 n/a w/ +200k. It's in my sig. It also has a 4 year old Catco catalytic converter. It scored much better when new. I should replace it this year.

markusparkus

iTrader: (1)

congrats!

driftxsequence

iTrader: (8)

OP here, took the sniffer test yesterday. HCs were practically non existent. i had the air pump going straight to the cat. didnt think about it and by the time i got to line it was glowing red hot from sitting there for so long

before while waiting in line i popped my hood and didnt have a screw driver to lean out my idle so i failed for my CO being too high. ill be going back shortly to do a retest and get that squared away. my car will finally be legal!!

driftxsequence

iTrader: (8)

Good news! I passed with flying colors. HCs were around 30, CO was nonexistent now that i lowered my idle mixture and all.

now i have a new problem...they went to pressure test my tank this time and it failed. basically as soon as they pressurize the tank it drops instantly. i thought it was due to a cracked line but the previous owner put in an after market tank. it has an extra line coming off of it (i can get a picture if it would help) i have no idea where it goes.

tweaked

iTrader: (4)

Plug it. But it probably goes to the charcoal canister.