Sc400

[Bandit]

While changing out my Climate Control Unit last night I disconnected the battery.

After the installation I took the SC400 out for a test drive and noticed an improvement in performance.

I don't know where, possible Planet Soarer, I read that someone had reset their ECU by disconnecting the battery and they had a noticeable improvement in performance. I didn't think anything about it at the time, until last night.

There is a stretch of road just before the turn off to my house, there are no side streets, so periodically I turn onto this stretch and wind her out. The average top speed in this short stretch is approximately 80mph before I start braking to turn. Last night I had just hit 90mph when I started to brake. I thought that's odd, and then forgot about it.

Then, today, after leaving work, there is a Stop sign that then merges onto another road to the left. Normally when I come out of there, the wheels will spin a little, the back end will kick out slightly and then it shifts up and stops spinning and grabs traction. What I noticed today is that with the same amount of throttle, the tires started to spin, the back end kicked out and then the tires started to squeal. The tires continued to spin even after it shifted and the back end stayed clossed up for about twice the distance than it normally does.

I would like some of you 400 owners to try this as a test and see if this is noticeable to anyone else. Disconnect the battery for several minutes and then go out and drive normal for several miles and then take it to one of your test stretches, somewhere that you know how it performs everytime to go there and see if there is any difference in performance.

Another thing that I noticed is that when I accelerate hard, as the rpm's climb, it sounds as if the exhaust note is out of balance. I would hear a "wah wah wah" sound. Like when you have two strings on a guitar out of tune or when a twin engine plane has to engines out of balance. After resetting the ECU this imbalance is gone.

Report back what you experience.

[Lexual]

Same thing just happened with me, got the car back from the shop from the electrical fire it had and she kicked alot more wierd stuff

[SPORTcoupe300]

I've got a 96 SC300 5spd and I've noticed the same phenomenon.

One more thing I noticed is after this ECU reset, the car will idle at a much lower RPM.

Only thing that sucks is the ECU relearns within a couple of days.

I'll play with it some more and see if it might be worthwhile to install a switch that'll cut the power to the ECU.

That would be pretty funny though.

You're standing at a red light, the guy next to you revs his engine.

You rev yours to accept the challenge.

To your opponents surprise, you then proceed to shut off your car.

Wouldn't want to cut power to the ECU while your car is on. :P

[jzz30]

i once read that a supra ecu de tunes it self when the engine ecu sences a knock it takes away about 30hp or something. the cure to this is to disconnect the ecu or the fuse. i think the same thing is happeneing and that this knock stuff in the ecu is in all or many toyota ecu's and is killing horsepower.

you guys fillin your cars up with high octane? well maybe your gas station is lying to you

[Bandit]

I'm curious if the ECU Log has anything to do with the ECU adjusting for such things as insufficient octane, O2 sensor problems, air fuel metering, etc.

If the ECU senses any of these, does it adjust and stay adjusted for them?

[Lexual]

I just noticed today while driving around I have lost alot of low end...when the car went in to get the harness replaced it came back out low end happy then it went back in for valve adjustments and the timing belt replaced now i have less low end ummph but it shifts harder...what the heck is that???????? I use to be able to do a brake stand on any surface not only select but when it shifts now it does push you back into the seat more and you can feel it shift harder. Anybody know whats going on with it???

[Lexual]

Out of bordem i went out disconnected the battery then reconnected and went for a spin little more power broke loose little easier till the end of the drive then back to where I started......