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Airpump? Way to trick system into thinking its still on?

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Old Jul 8, 2005 | 09:31 AM
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RX7Wishing's Avatar
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Airpump? Way to trick system into thinking its still on?

I want remove my airpump without the reported side effects of doing so. (lower vaccum,rougher idle, slightly sluggish from a dig.) Is there a way to trick the system into thinking that it is still present without the need for a aftermarket ECU? I am 400 bucks away from having the PFC, so i can obviously wait. But if their is a way to remove it and place a resister of some sort then i figured this would be a fun weekend project for me.

Discuss......

~Jay
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Old Jul 8, 2005 | 09:38 AM
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GUITARJUNKIE28's Avatar
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if you're getting an ems anyway, i'd just keep it on for now. i don't think the hastle of doing things like that is worth it until you do it all....but that's just me.
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Old Jul 8, 2005 | 09:45 AM
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The only effect I observed when I removed mine was not foolable. That is, it is a physical effect of no air injected into the manifold. It messes up the idle. Yes, the PFC fixed it, but I lived with it for two years before I got the PFC. At the time the car didn't have a cat. so I didn't need the pump (most "single stage" cats need air). You will probably need the Greddy pulley kit and belt, because I don't think you can get a belt to fit without the pump otherwise.

I have since added a Random Tech 5" dia. metal wound cat which doesn't need the air pump - it's a "two stage" cat with rhodium and platinum.
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Old Jul 8, 2005 | 09:48 AM
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GUITARJUNKIE28's Avatar
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^ you can always use a 4 rib belt. they're easy to find in that size, although not the very best solution.
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Old Jul 8, 2005 | 10:03 AM
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BOOOYAHHHH!
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i already have a belt that eliminates the pump . Thanks for the comments guys
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Old Jul 8, 2005 | 10:38 AM
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It would be VERY complicated to trick the ECU with no air pump. Basically you'd have to fool the O2 sensor's output only during times when the air pump would be on. Probably not too hard to build a circuit like that if you're an EE, but that's a lot of effort that can be saved by just going PFC.

Dale
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Old Jul 8, 2005 | 11:23 AM
  #7  
RX7Wishing's Avatar
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lmfao... yea.,...**** that.... ill just wait another month or so for the pfc. haha
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Old Jul 8, 2005 | 03:20 PM
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I removed my pump and had no ill effects with the engine at all. I started by just unplugging it and nothing changed so then I went to eliminating pipes and blocking off. Still same idle and and running conditions. Have you tried just unplugging it to see if it changes anything ? ? ?
This is my new air pump.

Last edited by CantGoStraight; Jul 8, 2005 at 03:26 PM. Reason: add picture
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Old Jul 8, 2005 | 05:02 PM
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sorry to jack this thread, but whats the benefit of removing your air pump? what does it even do?!
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Old Jul 8, 2005 | 07:36 PM
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Originally Posted by BobfisH
sorry to jack this thread, but whats the benefit of removing your air pump?
You gain .05 hp below 3000 rpms and shed a couple pounds in exchange for a bad idle and rough starts .
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Old Jul 8, 2005 | 07:46 PM
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tt2323's Avatar
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I've went without an airpump for awhile now. No wierd idle or nothing. Glad its not in the engine compartment anymore
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Old Jul 8, 2005 | 07:47 PM
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It also makes the engine bay look less cluttered which makes it look a lot cleaner IMO.
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Old Jul 8, 2005 | 07:54 PM
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Talking

Let's analyze what is happening and try to figure a solution for no air pump with a stock ecu.

(1) The O2 feedback system tries to keep the O2 voltage output at a fix value by changing fuel mixture "AFR".
(2) The air pump and ACV force air into the exhaust manifold "before the O2 sensor" and into the cat.
(3) Removeal of the AP stops the extra air injection befor the O2 sensor. Thus the exhaust gases have less oxygen to complete burning before reaching the O2 sensor.
(4) The O2 sensor now thinks the AFR is too rich. Lower voltage means leaner. Higher voltage means richer. Thus the voltage is too high.

Now I'll let you-all try to figure how to reduce this voltage using wire and one electronics part.
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Old Nov 2, 2006 | 08:02 AM
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From: dc
low voltage = lean
high voltage =rich

thx

Last edited by raptor17; Nov 2, 2006 at 08:22 AM.
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Old Nov 2, 2006 | 08:35 AM
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From: raleigh/durham
sorry to get off topic here, so having the airpump on and having a WBO2 sensor that is located before the cat will give you very off AFR readings because of the air that is being pumped into the exhaust manifold?
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Old Nov 2, 2006 | 04:25 PM
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From: mooresville
^ yes
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