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could this be the reason why i get poor mpg?

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Old 05-31-05, 01:05 PM
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could this be the reason why i get poor mpg?

this first picture shows the sensor with the wire connecting to it and the wire is exposed...



the second picture shows the protective wrap that covers the wire connecting to the sensor..if you notice closely you can see where the wrapping has melted and fused together causing it to shrink...


the third picture shows the sensor and the exposed wire right were it connects to the sensor...



little background info:
10th aniv:
FMIC
Blow off valve
turbo timer
miles per gal = 9-10 =(

hopefully it will work now ...
Attached Thumbnails could this be the reason why i get poor mpg?-sensoragain.jpg   could this be the reason why i get poor mpg?-sensoragain1.jpg   could this be the reason why i get poor mpg?-sensoragain2.jpg  

Last edited by apreludem; 05-31-05 at 01:21 PM. Reason: correct post
Old 05-31-05, 01:15 PM
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yeah bad 02 sensor can play a big part of your bad mpg. I wouldnt say it was the main cause. but you should probably do the 60,000 mile tune up on it. replace all filters and 02 sensor. And reground the block and chassis. Youll probably get way better gas mileage.
Old 05-31-05, 01:17 PM
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i was always thought that a bad O2 sensor made your engine check light come on...cause mine is off =/

Im assuming this because on my prelude ( yeah i know its not the same car) my o2 sensor when out and the light switched on.
Old 05-31-05, 01:22 PM
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Bad 02 does throw out a code, you have a S4 so I don't know how you would check code to see what else has failed. Maybe your light has a bad soder point or is just bad.
Old 05-31-05, 01:27 PM
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"Bad 02 does throw out a code, you have a S4 so I don't know how you would check code to see what else has failed. Maybe your light has a bad soder point or is just bad."

quick question, would my check light still come on when i first turn the car on if there was something wrong with the light? cause mine turns on when i insert the key and put it in the "on" position.

to clarify: it turns on along with the rest of the other lights.
Old 05-31-05, 02:33 PM
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Yeah, that O2 sensor is shot.... you'll get a bit more when cruising with a new o2 sensor..

I would say that your bad MPG is more to do with your mods.... says FMIC, BOV, Turbo Timer.....

Remember, anytime you hit boost, you are no longer running of the o2 sensor, your fuel econ goes down!

Hell, I'm soon going to be sticking an 02 sensor on my car with the Haltech just to squeeze a bit more out of it on the highway!!!
Old 05-31-05, 03:29 PM
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thsi is the thing though...i have never gone above 4k rpms in my car...i rarely hit 4k ...mostly take it to 3-3.5k rpms =(
Old 05-31-05, 03:39 PM
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Ahhh! Carbon. Redline the sucker. Take it to about 7.5k a few times to clean all that nasty carbon out.
Old 05-31-05, 04:00 PM
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Originally Posted by apreludem
i was always thought that a bad O2 sensor made your engine check light come on...cause mine is off =/

Im assuming this because on my prelude ( yeah i know its not the same car) my o2 sensor when out and the light switched on.

You have an S4, there is no ECU operated Check Engine Light..
Old 05-31-05, 06:14 PM
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"You have an S4, there is no ECU operated Check Engine Light.."

by this i mean throws out codes
..doesnt it still spit codes at me? cause its not giving me any codes =/
Old 05-31-05, 08:50 PM
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If you have an S4, the only way to get codes is to make the ECU tester lights, and then plug it into the diagnostic plug in the engine bay. If your O2 sensor was chilling in siberia, you would be none the wiser unless you looked at for the O2 sensor, or you pulled the codes by plugging into the diag plug.

The dash operated CEL (which doesnt exist), will not alert you to your vacationing 02 sensor.

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Old 05-31-05, 11:19 PM
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i think i confused everyone and myself...so i'll try this again =P I have the tester lights and they show zero codes..if my o2 sensor was out should the ECU tester lights show something?
Old 05-31-05, 11:26 PM
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Originally Posted by apreludem
i was always thought that a bad O2 sensor made your engine check light come on...cause mine is off =/

Im assuming this because on my prelude ( yeah i know its not the same car) my o2 sensor when out and the light switched on.
On the S4 rx-7 a bad O2 sensor does throw a code but it can only be read with an engine code reader. Also if your shifting at 3-4K every once and a while drive with it at 6k or so. Heating up the O2 real good every now and then helps keep it clean. Remember the O2 sensor operates above 600 degrees, so you need to heat it up.
Old 05-31-05, 11:32 PM
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reason i dont drive it past 3-4k is because dyno sheet showed i was running lean which makes no sense...unless the previous owner messed around with something and made the car run rich or something...
Old 06-01-05, 03:45 AM
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Lean is baddd!! since you have ATF gage try tweaking it out to stoch... Lean = boom, Rich = say bye bye gas, Stoch = eh... its ok... but thats from my previous experience...
Old 06-01-05, 08:29 AM
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Lean.. at high RPM's on the stock fuel system.... you talking at boost or under light throttle.. what were the numbers???????
Old 06-01-05, 08:34 AM
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im trying to find the dyno...i think the guy who previously had this car did something wrong ...


k, i found this dyno sheet...this is stoich right?


if this is stoich or lean..why am i getting 9-10 mpg? lol
only thing i can think of is..this dynosheet does not belong to my car..and the guy who i bought this car from lied? =/



Edit: i found the link he wrote before he sold the car...might help those trying to help me =P
https://www.rx7club.com/time-slips-dyno-128/dyno-modded-10th-ae-295831/


basically when i bought the car i was expecting it to be running lean..and therefore i would baby it so i have never gone past 4k rpms...well since the first two weeks i had her i noticed my gas mileage was horrible...so i started thinking if its actually running lean or rich? ...i did my mpg and sure enough..i got 10 miles to the gal....
Attached Thumbnails could this be the reason why i get poor mpg?-dinorun10thaniv.jpg  

Last edited by apreludem; 06-01-05 at 08:50 AM.
Old 06-01-05, 02:53 PM
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Wonder what kind of sensor they used.. And if they used like a tailpipe system, if Ape has a full emissions suite.
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