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Power mode or not?

Posted: Sun Dec 26, 2010 11:49 pm
by zagarus
Alright, so I just completed a 5spd swap on my 1992 Legacy SS. Went surprisingly smooth and had it done in about a day. For the wiring side of things all I've done at the moment is snip the wire to the ECU that tells it if the car is an auto or a 5spd (pin 20 on B48 I believe). I also removed the TCU and the inhibitor box or some sort. Car drives fine, idles fine (except for the somewhat loud syncros in 1st and 4th).

Now my issue is this, off the line if I stomp the pedal and accelerate through the gears the car pulls hard and all I can do is giggle like a school girl. However, if i'm cruising along and stomp on the pedal it doesn't seem to accelerate as hard as if I were stopped at a light.

Is the power mode for the automatics controlled by the TCU or the ECU? Having the TCU removed I can't see this being the issue and maybe it is some other sort of electrical gremlin. Any insight would be much appreciated.

Thanks

Tom

Re: Power mode or not?

Posted: Mon Dec 27, 2010 6:29 am
by wtdash
Hi,

First, I'd Search for posts by Legacy777. He also has a website that details this swap...may have some answers.

I've read that the Power mode is related to TPS position and how quickly the pedal is depressed. And I know from my experience that the Power mode can be turned ON permanently by grounding a pin on the TCU. So...I'd say Both...not a helpful answer.

Do you think this is just turbo lag? What RPM and Gear are you feeling the lack of acceleration? I know my Forester's 5-speed doesn't 'take off' when I give it the Go pedal in 4th or 5th, 'til boost comes on. Whereas my Legacy's 4EAT will kick down a gear or 2 and jet.

TD

Re: Power mode or not?

Posted: Thu Dec 30, 2010 10:53 pm
by DevC
Try downshifting haha

Power mode is just 4eat shift patterns, w/ a 5-speed, you are power mode.

Re: Power mode or not?

Posted: Thu Dec 30, 2010 11:37 pm
by PhyrraM
With an automatic, even without a down-shift, slip in the torque conveter can allow boost to build slightly faster by raising the RPMS and loading the engine slightly more than a direct "no slip" clutch coupling.

+1 -- downshift


To answer your question, there are no changes to the engine ECU during Power Mode.

Re: Power mode or not?

Posted: Fri Dec 31, 2010 12:28 am
by kimokalihi
Yeah it's all about the RPMs and load.

Re: Power mode or not?

Posted: Fri Dec 31, 2010 4:06 am
by beatersubi
My 5mt wagon seemed to accelerate harder if I rolled the throttle open rather than 'whacked' it open.

Re: Power mode or not?

Posted: Sun Jan 02, 2011 10:56 pm
by Legacy777
I'm assuming you bypassed the starting circuit so you could start the car?