3rd Generation Specific (1993-2002) 1993-2002 Discussion including performance modifications and Technical Support Sections.

Disabling an air pump, without removing it!

Old 12-30-12, 09:20 AM
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Disabling an air pump, without removing it!

So, is this possible? Trying to keep the car stock looking, has to pass a visual inspection..
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Old 12-30-12, 09:55 AM
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Just unplug it. But, if you're on the stock ECU, it's not worth it - the stock ECU will run like crap with the airpump unplugged or removed.

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Old 12-30-12, 10:00 AM
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May as well leave it functional if you have emissions. Even on a standalone there's no real performance gain without it. And if you still have the stock cat, it may shorten it's life.
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Old 12-30-12, 10:52 AM
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It automatically shuts off after ~3200ish rpm, its not a real drain on performance.
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Old 12-30-12, 10:54 AM
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Not to mention it injects secondary air at low rpm. So you will have a rich idle and low end and it'll run like garbage unless you properly delete it an retune for it.
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Old 12-30-12, 11:09 AM
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Originally Posted by Mrmatt3465 View Post
Not to mention it injects secondary air at low rpm. So you will have a rich idle and low end and it'll run like garbage unless you properly delete it an retune for it.
Air injection is post combustion chamber.
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Old 12-30-12, 11:44 AM
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Originally Posted by dguy View Post
Air injection is post combustion chamber.
I'm sorry I misunderstood the purpose of the Air Control Valve. Due to its placement I assumed it injected into the LIM. After reviewing the FSM it states that the Air Pump supplies air to the Air Control Valve, which is then directed to one of three places: The exhaust port, the three way catalyst, or the relief air silencer.

This therefore implies that the air pump is essential to catalyst life and nothing more. Learn something new everyday.

Matt
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Old 01-03-13, 07:06 PM
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I'd like to briefly clear up some misconceptions about the air pump by referring to some information Mazda has published over the years. The basic emissions reduction strategy with airpump + catalyst was developed for the series 2 Rx-7 (12A engine, carburetor)

1) The air pump on the FD does not directly inject into the intake manifold, but on previous rotaries it did. It was part of the "Anti-afterburn valve" to reduce popping in the exhaust. On the FD, this functionality was replaced by refined control of the idle speed valve.

You can see the old anti-afterburn valve on the 2nd gen Rx-7 ACV:



2) One of the major purposes of the air pump is to "band aid" the diluted mixture produced by high overlap between and exhaust stroke. The overlap reduces combustion stability, increasing misfire, and requires a rich mixture at idle & low load. The air pump, through the port air system, actually injects fresh air into the engine as this overlap phase occurs.

This was originally developed on the 12A engine like I mentioned above. You can see some information on their experiments with different exhaust port air injection nozzles here:




The air pump's fresh air injection effect is one of the reason why the stock ECU runs like crap when you delete the airpump. Basically, the car was originally tuned around this fresh air being drawn back into the engine.
Attached Thumbnails Disabling an air pump, without removing it!-fc_acv.jpg   Disabling an air pump, without removing it!-airpump_idle.png  
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Old 01-03-13, 07:20 PM
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Originally Posted by mortenf View Post
So, is this possible? Trying to keep the car stock looking, has to pass a visual inspection..
Arrggghhhh , someone did not even read section F!
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Old 01-05-13, 05:41 PM
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Originally Posted by cewrx7r1 View Post
Arrggghhhh , someone did not even read section F!
What, the section F about Fuel in the sticky?

My question was about dissabeling the pump WITHOUT removing the pump it self, belts, hoses and so on.. As stated, the car has to pass a VISUAL inspection, it doesnt need cats, air valve etc, as there is no way that the inspector is going to notice that.. It has PFC by the way..

So i could just unplug the connector, and the pump would be dissabled?
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Old 01-05-13, 08:06 PM
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Originally Posted by mortenf View Post
...... As stated, the car has to pass a VISUAL inspection, it doesnt need cats, air valve etc, as there is no way that the inspector is going to notice that......
Well, you know your country's inspections, but here in the U.S. I'd be very surprised if they didn't notice the absence of a cat and the air line feeding it. Regardless, if you remove the cat for an midpipe, especially on the stock ECU, it's dangerous to your engine. Search for info on BOOST CREEP.
Originally Posted by mortenf View Post
......
So i could just unplug the connector, and the pump would be dissabled?
Yes, but "as stated", there is no decernible performance value in doing so. And "as stated" if you're on the stock ECU, owner's tend to have other issues with goofy idle, hesitation on throttle tip-in etc. And if you keep the stock cat to avoid the risk of CREEP, then "as stated" running with no airpump will likely shorten it's life.

Basically, there is no good reason to just unplug the AP, and a few good reasons to leave it functional on a reasonably stock car that has to pass emissions inspections.
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Old 01-05-13, 10:10 PM
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If you have the air pump working already, you don't gain much by disabling it. It's got a clutch.
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Old 01-06-13, 12:39 AM
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Originally Posted by mortenf View Post
What, the section F about Fuel in the sticky?

My question was about dissabeling the pump WITHOUT removing the pump it self, belts, hoses and so on.. As stated, the car has to pass a VISUAL inspection, it doesnt need cats, air valve etc, as there is no way that the inspector is going to notice that.. It has PFC by the way..

So i could just unplug the connector, and the pump would be dissabled?
Lack of the knack!
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Old 01-06-13, 01:29 PM
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Ok, ill try this again, for those that did not bother to read my reply.. It has PFC. The inspection is purely visual, meaning that they are only going to open the hood, to have a look around etc. The car only has to drive a couple of miles from the workshop, get inspected, and then its single turbo time!

Thats why i want to know if i can dissable the air pump, without removing it, so that there isnt a big gaping hole where it should be..

I am not trying to gain any performance, just want to have it stock looking for this inspection...
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Old 01-06-13, 01:50 PM
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I don't understand what you mean by "disable." The secondary air injection system is complicated. The pump itself has a clutch. The air is directed to the Air Control Valve (ACV) which then directs air to the exhaust ports or the split air pipe/catalytic converter. There are a bunch of solenoids that control the ACV.

Do you want the car to appear as if nobody has tampered with it? Then hook everything, or almost everything up. There are lots of hoses, electrical connectors, etc.

As far as "disabling" the pump, well you can basically set it up to so that the clutch never engages. Or you can unplug/misroute the ACV solenoids. But if the goal is to pass a visual inspection, that kind of tampering may make it fail depending on how hardcore the inspector is. So why not put it to stock, or very close to stock?

The key to remember is that the secondary air injection system on this car consists of

1) mechanical, belt-drive pump with clutch
2) pneumatic/diaphragm controlled valves
3) solenoid valves to direct air to the diaphragms

So which of these do you want disabled? If they are just looking under the hood and not hooking up a tailpipe tester, I'm not sure what you gain by unplugging or totally removing anything. If you pull the belt off or otherwise modify the belt system, well that could be obvious tampering to an inspector. If you go unplugging solenoids, relays, etc... well why do that? It's more work to figure out what to unplug safely. If you start pulling pipes/hoses off, that's also tampering.

The secondary air injection system is so complicated that it's usually best to either have it very close to stock or removed altogether.
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Old 01-06-13, 02:21 PM
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If its just for a visual inspection like you're saying, why don't you just leave it plugged in? Yes unplugging it will disable it but I don't understand why you don't just leave it? You don't think they'll notice unplugged connectors while they're snooping around?
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Old 01-06-13, 02:28 PM
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Originally Posted by mortenf View Post
Ok, ill try this again, for those that did not bother to read my reply.. It has PFC. The inspection is purely visual, meaning that they are only going to open the hood, to have a look around etc. The car only has to drive a couple of miles from the workshop, get inspected, and then its single turbo time!

Thats why i want to know if i can dissable the air pump, without removing it, so that there isnt a big gaping hole where it should be..

I am not trying to gain any performance, just want to have it stock looking for this inspection...
It's sounds like YOU don't bother to read the replies....or not telling the truth about what you're really trying to do. If all you're going to do is drive it somewhere for an inspection and then back to the shop to go single, why in the hell did you start this thread? Just drive it there WITH the AP hooked up. What difference does it make if it's disabled or not? After all, you're "not trying to gain any performance".
You keep asking, we keep answering.
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Old 01-06-13, 09:01 PM
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So... You want to disable the air pump on a car that is already running a PFC...

...Because you need to pass a visual inspection only?

So unplugging a small hidden two pin connector to disable the air pump serves *what* function if the inspector is just going to *look* at the car??

As has been stated by a whole bunch of knowledgeable people, the air pump has a clutch on the front of it. Above 3200rpm the clutch is DISENGAGED. Meaning it takes approximately 0.15 HP to rotate it. Basically it free spins with no load after 3200.
I am not trying to gain any performance, just want to have it stock looking for this inspection...
Then leave it alone. It will look stock with the connector plugged in. Problem solved. Unplugging it will not make the car look "more stock" to pass a visual.
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Old 01-07-13, 05:22 AM
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Thanks for the informative answers.

The whole story is that the car belongs to a buddy of mine, that took it to a shop to get the engine rebuilt, ported and so on. Long story short, he ended up with a engine that sat in the car and a whole lot of missing parts.

The car now sits in my shop, and the goal of all this is to get it running and passing the inspection, using the least amount of money on parts, that will be removed later on, when it goes single. The reason for wanting the air pump to still be there, is as stated above, it kinda leaves a big "hole" right in the middle of the engine compartment.. Its not like the inspector is going to dissassemble the intake manifold, to look under there, so the lack of solenoids/valves and hoses are not that important. Most of them are there, just not connected and functionable.

It just has to look like its stock at a glance, and that means that the pump should be there, and hooked up to the fan belt. Where the hoses go, is not that important, im thinking about just routing them under the car, and plugging them there.

I guess i could have rephrased my question to something like "Is there a way to stop the air pump from pumping air, so that its safe to plug the hoses?"
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Old 01-07-13, 10:27 AM
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Ah, the truth will out. But again your question was already answered. The air pump is on a clutch that needs to be engaged so yes, you can just unplug it, though the car may run like ****.


Originally Posted by mortenf View Post
Thanks for the informative answers.

The whole story is that the car belongs to a buddy of mine, that took it to a shop to get the engine rebuilt, ported and so on. Long story short, he ended up with a engine that sat in the car and a whole lot of missing parts.

The car now sits in my shop, and the goal of all this is to get it running and passing the inspection, using the least amount of money on parts, that will be removed later on, when it goes single. The reason for wanting the air pump to still be there, is as stated above, it kinda leaves a big "hole" right in the middle of the engine compartment.. Its not like the inspector is going to dissassemble the intake manifold, to look under there, so the lack of solenoids/valves and hoses are not that important. Most of them are there, just not connected and functionable.

It just has to look like its stock at a glance, and that means that the pump should be there, and hooked up to the fan belt. Where the hoses go, is not that important, im thinking about just routing them under the car, and plugging them there.

I guess i could have rephrased my question to something like "Is there a way to stop the air pump from pumping air, so that its safe to plug the hoses?"
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Old 03-10-14, 05:39 PM
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Smile Question relating this thread! This is GREAT information!

Originally Posted by dguy View Post
Ah, the truth will out. But again your question was already answered. The air pump is on a clutch that needs to be engaged so yes, you can just unplug it, though the car may run like ****.

Sorry to bring up an old thread. All of this information is so useful! Fantastic! I would like to get a high flow cat or a mid pipe to get rid of the factory convertors in order to gain some HP. I would like my air pump to operate.

Is it possible to make the air pump operate with this modification?

The car has a downpipe on it that looks after market and I just ordered a cat back racing beat exhaust.

Should I just go for the gusto and remove the air pump system and have my ecu reprogrammed?

I am running stock boost and the rest of my car is stock. Should I be concerned about boost creep?

Sorry for the noob questions and thread hijack but I'm trying to learn.
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Old 03-10-14, 09:15 PM
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Installing an aftermarket cat has nothing to do with any of the other components. Basically leave everything as is and it will continue to work the same way. Yes, a tune is recommended. If your running a cat, leave the air pump alone.

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Old 03-10-14, 11:12 PM
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Originally Posted by thewird View Post
Installing an aftermarket cat has nothing to do with any of the other components. Basically leave everything as is and it will continue to work the same way. Yes, a tune is recommended. If your running a cat, leave the air pump alone.

thewird
So the air pump has to have a converter for normal operation but does not matter if it's aftermarket or not? Do the high flow cats have the air pump fittings on them or do I have to weld up my own?
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Old 03-10-14, 11:28 PM
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Aftermarket cats still come with the air thing, you might just need to modify it a bit to make to the stock FD side.

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Old 03-11-14, 01:17 PM
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Many HF cats specific for the FD have the pipe. Bonez does anyway. ---> https://rx7.com/store/rx7/fdexhaust.html
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