2nd Generation Specific (1986-1992) 1986-1992 Discussion including performance modifications and technical support sections.

question about air flow.

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Old Mar 11, 2006 | 01:46 AM
  #1  
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question about air flow.

okay,

my car smells like it's running really rich, is this because there is not enough air flow
to my k&n air filter? or am i just burning up way to much fuel cause of another problem?
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Old Mar 11, 2006 | 01:57 AM
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They run rich. Most likely you are fine. A tuneup may improve the situation, especially check the TPS and o2 sensor.
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Old Mar 11, 2006 | 01:59 AM
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From: canada
how much do you think it would help if, i bought a headlight cover with an air vent on it, or took out my left parking light?

and so how many clicks should i get to the tank?
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Old Mar 11, 2006 | 03:32 PM
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Your k&n intake and a headlight cover do effectively nothing to actually adjust the mixture...

remember, the afm is metering the actual amount of air coming in and then the ecu is deciding how much fuel to put in. While adding these parts decreases the energy required to get a cold air charge you're overall mixture isn't going to change. The only way to effectively change the mixture is through an ecu adjsutment, whetehr with an afc or standalone.

If you're complaining about idle smell, you do have an s4, so idle mixture is adjustable, but often not recomended - I believe there is an aarticle in the howto sections of fc3spro.com or in the archives of this forum - a search will often pull up people who have changed it and can't find a good spot again.

Mazda mapped the RX-7s rich in the ecu, you can live with it, or try to tune it. You probably also want to check your vacuum lines in case any are leaking (though this typically results in a lean condition). Also, do you have a catalytic converter? Without one Wankel Rotaries stink pretty badly.
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Old Mar 11, 2006 | 04:29 PM
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If your O2 sensor is getting old does it cause it to run alot richer then normal? Mine looks to have been replaced at some time but I'm running pretty rich too and would like to trim it down a bit before going with something like a SAFCII
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Old Mar 11, 2006 | 04:56 PM
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stand alone fule managment fixes that, if you wanna get hardcore
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Old Mar 11, 2006 | 06:59 PM
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The O2 sensor does affect mixture when the ecu is using it; however, most times that you would be using it you not be physically able to smell it.

The ecu has clsoed loop mode and open loop mode, when the O2 sensor matter and not.

For the o2 sensor to be used you must be below 3500rpm with no sudden harsh throttle/load changed - so like cruise control on the highway.

Originally Posted by uRizen
If your O2 sensor is getting old does it cause it to run alot richer then normal? Mine looks to have been replaced at some time but I'm running pretty rich too and would like to trim it down a bit before going with something like a SAFCII
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Old Mar 11, 2006 | 10:39 PM
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wow thanks guys your helping alot.

so i burn about 40 canadian dollars of premium every 230-240 km. thats also it idling for about 30 minutes inbetween fill ups, is that good or bad? i'm so sorry i sound like a newb but this is my first wankel engine.

and yes i took out my cat converter, and i have dual magnaflow exhausts.

and i know i'm going to sound like a newb, but whats an s4 or s5. i have an 88 gxl stock
except the exhausts and the k&n air filter.
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Old Mar 11, 2006 | 11:06 PM
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check the FAQ and do a FULL tune up
even my car gets 27.3Km per gallon city (17mpg)
and 38.6Km per gallon Highway (24mpg)
us gallons not shure if theirs a diff.
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Old Mar 12, 2006 | 12:59 AM
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Noooo

NOOOOOOOOOOOOOOOOOO
The reason your car is acting like crap and probably slowing down drastically is because you are running premium fuel!!!

Search octane on the board! The ideal octane would be 82 for an NA RX-7 due to the long combustion chamber (a sliver across the trichoidal curve) prevents the flame front from spreading as quickly as need be.

Running anything above 87 octane ends up costing you more money and costing your engine life in carbon buildup and incomplete burns. I would suggest you run a water cleaning treatment and switch to lower octane fuel as soon as possible!

On s4, and s5: s4 is 2nd gen series 4, 1986-1988, and series 5 1989-1991. The big differences between these were the trim package, the rotor compression (9.4s4 to 9.7 s5), the rotor weight (8000rpm redlin in s5s), the afm (door s4 to cone s5).


Originally Posted by ninjasound
wow thanks guys your helping alot.

so i burn about 40 canadian dollars of premium every 230-240 km. thats also it idling for about 30 minutes inbetween fill ups, is that good or bad? i'm so sorry i sound like a newb but this is my first wankel engine.

and yes i took out my cat converter, and i have dual magnaflow exhausts.

and i know i'm going to sound like a newb, but whats an s4 or s5. i have an 88 gxl stock
except the exhausts and the k&n air filter.
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Old Mar 12, 2006 | 05:20 AM
  #11  
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...well i fail at life.
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Old Mar 12, 2006 | 05:22 AM
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From: canada
so tell me, how do i run a water treatment?
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Old Mar 12, 2006 | 05:40 AM
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to run a water treatment
find a vac line that sucks all the time, bring it to a gallon of water, rev it up to 4k ish, let it suck the whoel ****, and ur cool
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Old Mar 12, 2006 | 07:26 AM
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<*sigh*>

1) RX-7's tend to run rich. You are not running a cat. The car exhaust will smell. Period.

2) No, you haven't screwed up your engine by running premium gas. You most likely don't need to run water through the system. The car will actually run better on lower octane gasoline, so this is what people run (including the racers)

3) #2 above does not apply to turbo-charged cars.


Good luck,

-bill
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Old Mar 14, 2006 | 08:39 AM
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The water treatment never hurts, it's almost never explicityly required, but even kevin landers suggests doing it regularly. http://www.rotaryresurrection.com/ro...injection.html is how to do it.
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Old Mar 14, 2006 | 08:54 AM
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If you are running very rich (ie. HORRID gas mileage, constant fuel smell) then there is something wrong. Start with a FULL tuneup as covered in the Haynes/Factory Service Manuals. Especially important is changing all the plugs and wires, filters and TPS adjustment.

Adding aftermarket products will not work as anything but a bandaid.
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Old Mar 14, 2006 | 01:20 PM
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From: WDC
Dont forget to check your fuel rails. Might as well take the UIM off, and replace all fuel injector hoses (rubber lines going to the rail) and Injector seals and orings.
Doesnt take long and will keep you from having a Car-be-que
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