air pump removal,,need a good explanation,,
 

hi guys ive read every post on airpump removal,, read this and someone please explain a few things for me thanks.
Ive removed the air pump from my japanese RX7 (no EGR),, now following in another members footsteps ive ground off the ACV and the other tube that runs through the back of the lower intake manifold (this makes the manifold look smarter and also theres no need for blanking plates)
Now what i dont understand is why when the air pump is removed the car idles like crap,,,,because grinding away all the air control stuff ive noticed that none of it has anything to do with the inlet manifold,, theres only one tube that goes from under the primary 2 middle intake ports (small rectangle shaped),, this leads up the manifold into the ACV ,(is filled with exaust soot),,,, this looks like some sort of system for using the exaust emmision but from studying all the air pump system air only travels to the cat. (i think unless emmisions a taken out of the cat and fed into the primary intakes????)
some expert please explain it all to me,,, i cant find the answers

Basically, theory is that Mazda compensated for the additional air from the airpump in the ECU programming. When that air is removed, the fuel mapping is off and runs like crap in the lower rpms. To counter act the problem, you either raise the idle or use a programmable ECU.

Sorry, but I'm pretty sure that is wrong. The ACV does not inject air into the intake manifold.

The ACV lets air into the exhaust manifold prior to the O2 sensor and without this extra air in the exhaust stream the computer thinks the car is running rich, and leans it out way too much. I don't know why everyone says their cars run rich after the airpump is removed, maybe it does smell a lot worse. But a few people have verified the lean condition with wideband AFR gauges.

edit:

Here's a diagram of the AVC from the FSM, notice no air goes into the intake, only the exhaust.

http://filebox.vt.edu/users/mattmck/rx7/ACV.jpg

Mahjik,,, i just read a complete guid on another site,,,basically the air bump pumps to 2 places the main cat and the exaust port in front of the O2 sensor,,,this is where the problems caused (with this air supply gone ECU settings at idle are shafted)
mahjik ive just bought a apexi power FC,,,,,,, will this make the car idle perfect when set up,???????

beat me 2 it afterburn,, u are 100% correct,,, can the apexi run the idle perfect?

Yes, you should be able to tune the PFC for no airpump idle.

only word i didnt like there is SHOULD,,, lol (i tried months ago unplugging the airpump,,,,car idles like plop)

bumping this. seems to be a lot of confusion regarding air-pump removal. so the facts are:

1. on stock ecu idle will be bad
2. this is due to running lean(not rich) and can be corrected with a programmable ecu (has anyone been successful at this?)

questions:

- does running w/o a air pump kill the catalytic converter?
- is there a writeup available?

The answer to your first question is yes, at least with the stock cat.

If you remove the airpump you will need to buy an airpump elimination pulley kit (Greddy, ebay, etc.). A better solution is to buy a kit that comes with an idler pulley, I think Pineapple Racing sells one?

If you don't have a standalone ECU you might have to deal with idle issues as mentioned above. For the record, I did eventually unplug my airpump for shits and giggles and my idle was fine. I also didn't notice any significant change in the air/fuel ratio... it stayed mucho RICH just like it was before. I was running a rx7.com chipped ECU, maybe that had something to do with it...

At any rate, the airpump isn't engaged at full throttle, so it shouldn't be robbing much power. I wouldn't worry about removing it unless you really want to make some room in the engine bay, or you are running a standalone ECU and can compensate for the idling problems.