Air Pump
Originally Posted by DaleClark
A wideband before/after would tell you if it's really richer or leaner. To me, it seems leaner, just from what I remember of messing with the idle mix screw on FC's. Rich sounds bogged down and "fat", lean is "stuttery". Rotaries typically like a rich idle, but not a lean idle.
Regardless, the O2 feedback is the reason for rough running without the air pump. Doesn't really matter if it's lean or rich - it runs crappy
.
Dale
Regardless, the O2 feedback is the reason for rough running without the air pump. Doesn't really matter if it's lean or rich - it runs crappy
.Dale
BTW, thanks Dale for replying to my earlier thread. And I just got your check valves in the other day.
Rotary Enthusiast
Joined: Feb 2005
Posts: 1,336
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From: Charlotte, NC
Here's my theory: There are two pipes comming from the Airpump. One goes to the main cat (which is after the O2 sensor-thus no input to the O2 sensor from that specific pipe)
The other one goes to the ACV which is bolted to the LIM. The O2 sensor does read this one. This is used to add air to the intake charge at idle because of the lack of air flow from sitting still (i.e. - at a stoplight)
(Airpump="pumping air")
When you remove the airpump, the idle becomes lumpy due to the rich mixture caused by the lack of air that Mazda was calculating when designing the "Map". And you also get the "popping" exhaust caused by the unburned fuel igniting in the CAT. The ACV on the 3rd gens replaced the BAC (a.k.a. - anti-afterburn) on the 2nd gens.
The other one goes to the ACV which is bolted to the LIM. The O2 sensor does read this one. This is used to add air to the intake charge at idle because of the lack of air flow from sitting still (i.e. - at a stoplight)
(Airpump="pumping air")
When you remove the airpump, the idle becomes lumpy due to the rich mixture caused by the lack of air that Mazda was calculating when designing the "Map". And you also get the "popping" exhaust caused by the unburned fuel igniting in the CAT. The ACV on the 3rd gens replaced the BAC (a.k.a. - anti-afterburn) on the 2nd gens.
Last edited by quicksilver_rx7; Apr 26, 2005 at 02:39 PM.
As I said above, the air pump doesn't inject air into the intake stream - only into the main cat and the exhaust manifold.
"Lack of air from sitting still" - huh? An engine is an air pump, it sucks air in no matter if it's sitting or going mach 9.
Dale
"Lack of air from sitting still" - huh? An engine is an air pump, it sucks air in no matter if it's sitting or going mach 9.
Dale
Rotary Enthusiast
Joined: Feb 2005
Posts: 1,336
Likes: 0
From: Charlotte, NC
Originally Posted by DaleClark
As I said above, the air pump doesn't inject air into the intake stream - only into the main cat and the exhaust manifold. "Lack of air from sitting still" - huh? An engine is an air pump, it sucks air in no matter if it's sitting or going mach 9
Dale
Dale
What's the point of the pipe going from the airpump to the ACV? And where does the exhaust manifold get it's air supply from?
And as always, thanks for being a smartass
Last edited by quicksilver_rx7; Apr 26, 2005 at 06:01 PM.
It's not the computer that's the problem. The ECU expects the extra air from the airpump to be going, so the idle mixture is richened. Without the air from the airpump, the mixture at idle is too rich and causes a very lumpy idle. There are two ways to fix it:
1. Get a programmable ECU and adjust the idle mixture
2. Increase the idle up to around 1100 rpms (on stock and rechipped stock ECU's)
1. Get a programmable ECU and adjust the idle mixture
2. Increase the idle up to around 1100 rpms (on stock and rechipped stock ECU's)
Can this be adjusted without an AFR meter?
Does the PFC ECU auto correct for unplugging and replugging in the air pump connector?
Last edited by s1mpsons; Sep 25, 2008 at 06:43 PM.
The point I was trying to make is that the airpump introduces fresh air into the system. And the removal of that air is what causes the rich condition. I WAS NOT trying to get into a science debate on the inherent properties of an internal combustion engine.
What's the point of the pipe going from the airpump to the ACV? And where does the exhaust manifold get it's air supply from?
And as always, thanks for being a smartass
What's the point of the pipe going from the airpump to the ACV? And where does the exhaust manifold get it's air supply from?
And as always, thanks for being a smartass
If you would take a little time to read the information in the Technical Manual section you can find all this information.
As it is you are merely rude and ignorant.
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