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Discussion Starter · #1 ·
Hey Everyone,

Well, I just swapped my 91 9000 for a 9-2x aero.

I love the car, it handles so much better than my 9000 and the transmission is great. Althought parting with the 9000 was rough.

Anyways.
I've been driving it around, and it feels like it doesn't accelerate, particularly in 2nd and 3rd, quite as smoothly as some of the other aero's and WRXs i've driven. It feels like between 2000-4500RPMs the throttle is unstable. It reacts like I'm not holding my foot steady on the gas, except that I am.

I was wondering if that is just how the engine reacts when it is pushed, or if it was possible that something wasn't tunned right, like the turbo or something. Or maybe I am just hypersensitive.

Thanks for your time everyone.

-Dave
 

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I have noticed the same thing. The only thing I can think if is that it is the a/c clutch engaging and disengaging. Someone stated that it disengages at full throttle. The only time that I notice the fluctuation is when I have the a/c is on. However I may be totally off.

It kind feels like my 90 mustang GT did when the clutch would start going bad and slip. But this should not be happening with less than 700 miles.
 

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Discussion Starter · #3 ·
Yeah, I'm still under 1000 miles and it happens even when I push it only moderately hard.

I will have to do some tests with and without the AC. The subaru dealer said the AC sucks up about 10hp... for whatever that is worth.

-Dave
 

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mine does it too. a bunch of the '05 wrx's were experiencing knock straight from the factory (search www.nasioc.com). most dealers would reflash the computer under warranty and the problem was solved. although i'm not hearing the "aluminum foil rattling around in the engine" knock sound, I wonder if that's it?

I also thought it might be cheap gas that the dealer put in it. but i ran that tank out, filled up w/ premium and the problem improved, but didn't disapear.

the subaru wrx computer is very smart and changes parameters to fix such things, so i'm guessing it will go away. after i hit 1000 miles and can start running the thing to redline, i think the computer will "learn" what's wrong and fix it. if not, i'll take it to the dealer.

p.s. first i'll slap on a utec, take it to the dyno and see if my tuner can't smooth it out. but for those who don't want to modify, it is a problem and should be taken to the dealer.

luke
 

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Discussion Starter · #5 ·
Thanks for the advice, I don't know if I will modify it, but I'm at mile 985 so maybe after an tank or two of good gas and more driving it will sort itself out.

-Dave
 

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You may want to consider resetting your ECU - especially if it originally learned with crap gas in the tank.

Just disconnect the negative battery terminal and stand on the brake pedal for a few minutes. When you hook it back up the ECU will have a blank slate. If you've had cheap gas in the car recently, run it to empty and fill it up with 93 octane (or the highest available in your area) and drive for 20 or so miles before you do this.

It may not completely remove the sensation due to factors previously mentioned in this thread, but it should help a lot.
 

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Discussion Starter · #7 ·
Hey Thanks man.

But what exactly is does resetting my ECU do?

Just let the engine re-configure the timing and whatnot?

Is this different than having a dealer flash my ECU?

-Dave
 

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Davess4 said:
Hey Thanks man.

But what exactly is does resetting my ECU do?

Just let the engine re-configure the timing and whatnot?
Exactly! :cool: Once you reset the ECU the car's brain will learn fuel and timing maps based on your driving habits. So make sure you drive the car like you stole it for the first 2-3 days :)

Is this different than having a dealer flash my ECU?
Much different. Having your ECU reflashed changes the default values in the ECU. It replaces the maps with more aggressive ones than the ECU will acheive from the factory. But don't discount the value of resetting your ECU. You should notice quite an impressive seat-of-your-pants increase in performance if the current maps your ECU has settled on are based on bad gas.
 

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Discussion Starter · #11 ·
Hey everyone,

Thanks!

I put a couple of tanks of 93 octane and reset the ECU. The car is running beautifully right now. The acceleration is much smoother.

I think the gas alone was starting to help it.

-Dave
 
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