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Big idle problem

Old Apr 16, 2010 | 10:24 PM
  #1  
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IL Big idle problem

i dont know was going on with my rx7! I have a S5 89 an the idle on the car is very strong when it starts ir reps at 2500 rpm an then it starts coming down very slow till it turns off onles i give it some gas. i had taken the air control volve of an had it clean but still the same promblem. can anyone point me in the right direction an is ther a good shop i can take it to in Chicago IL.
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Old Apr 16, 2010 | 10:38 PM
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sounds like your air control valve is bad and not holding a proper idle. Is this a TII or N/A? You can try adjusting the small screw that is on top of the throttle body on an N/A, it is usually covered by a rubber cap. On a TII, there is a screw on the BAC (idle air control valve) that adjusts idle.
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Old Apr 17, 2010 | 02:44 AM
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try what the poster said above but it could also be a huge vac leak or a bad maf.
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Old Apr 17, 2010 | 10:09 AM
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The ACV has nothing to do with holding an idle. Its job is to shut air to the exhaust ports, cats, or an air silencer. What it does depends on the what the ECU decides is required to maintain emissions.

Fix all vacuum leaks, adjust the TPS, and clean/test the BAC valve.
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Old Apr 17, 2010 | 01:00 PM
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Smile thanks

thanks guys ill do that ill get back to you guys with my results this week an wher could i get a cheap air control volve?
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Old Apr 17, 2010 | 07:38 PM
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Angry

I took of the air control valve and cleand it with W4 an i adjusted the idle on it by turning it with a flat head screw driver to the left but still i have the idlw how can i cheack for a leak an wher should i be looking ?
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Old Apr 18, 2010 | 10:13 AM
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Are you referring to the BAC valve or ACV? Where is this valve located?
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Old Apr 18, 2010 | 03:39 PM
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Yes, he implied the BAC, which I also mistakenly called (idle) air control valve forgetting there is also the ACV....

Has anybody such as the previous owner modified the throttle body to remove some components such as the thermowax? To check for vacuum leaks, you just look around and make sure all your vacuum hoses are plugged in and that nothing is left open. The best way would be with a vacuum gauge you can use to plug into a vacuum port. It will read how strong the vacuum is and whether you have a leak...

Another way, spray carb/choke cleaner around the intake manifold (be careful!!!). If the engine idles higher for a few seconds, you have a vacuum leak since it is burning up the fuel you sprayed. YOU CAN substitute this for propane (which is the proper way of doing things).
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Old Apr 18, 2010 | 11:57 PM
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IL

the valve i took of was this idle air control valve. an it stil.l has the same problem wher is the BAC located an i had this guy take a look at it i have a few line thet ar mising so im going to meet up tomorrow with another rotary fan the leav around my way an c if he can spare me the parts.
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Old Apr 19, 2010 | 10:45 AM
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OK. Please keep in mind that the RX-7 has a valve called the Air Control Valve, so we refer to our idle air valves at the BAC valve (Bypass Air Control) as it is called in the FSM/training manual to avoid confusion. Calling it an ACV is just going to confuse many people.

As I mentioned, most idle problems are caused by:
-maladjusted TPS
-vacuum leaks
-sticky/bad BAC
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Old Apr 24, 2010 | 10:59 PM
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thanks guy i changed my TPS an got a new air control valve an a few ajustments an my idle problem is fixt thank you guys
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Old Apr 27, 2010 | 04:12 PM
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How is it that some people have removed ACVs with a plate covering where it should be, I just bought a project turboII and the guy started taking everything apart and apparently forgot to give me that part. Why do some people get rid of it?
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Old Apr 28, 2010 | 09:42 AM
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ACVs are removed after that cats are removed because without the cats, the ACV has no function.

Unless you are talking about the BAC. In that case, people remove it because they are stupid.
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Old Apr 28, 2010 | 05:00 PM
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I am pretty sure its the ACV, its got a 3 bolts and 2 holes and its an akward shape. Whats the BAC so I can make sure it is still there then and if not make sure I get it.
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