SW20 Tune Ups and Hometune

[Rasker]

Hi Folks,
Someone said that the SW20 should self tune itself due to the ECU and the sensors, but every since I changed to 96 fuel I've gotten really bad milage out of it, even though the engine sounds a lot nicer.

The question is do SW20's need a tune up? and is Hometune any good?

Cheers

[deaf_rattle]

you may find that you think its more powerful from running the higher octane, with reality being you are just thrashing it more.

Lighten the foot abit and watch your economy go up.

[Rasker]

you may find that you think its more powerful from running the higher octane, with reality being you are just thrashing it more.

Lighten the foot abit and watch your economy go up.

Not thrashing it at all, it's getting less milage per tank on 96 than I did on 91. driving 28Km a day in heavy Auckland traffic, and getting 260Km a Tank.. that's shocking milage.

[KiwiMR2]

Iv'e forgotten if it was ever proven BUT a lot of people reset the ecu so the car can re-learn.

ECU learns and adapts depending on factors like fuel quality, knocking, and climatic factors. Over a period of time, the ECU may develop a conservative fuelling map which robs the car of performance (or if a problem occurs, e.g. bad fuel or an engine safety scenario.) Although the ECU continually adapts, it's very slow at doing so and can be reset to speed up the process.

Preferably after a drive (and the car now at full operating temperature), park, remove the key, and wait a couple of minutes. In the engine bay is a fuse box -- remove the 7.5A ECU-B and 15A EFI fuses. In the front compartment (not the cabin), remove the 7.5A ECU-B fuse... and then wait for at least two minutes before replacing them. With the fuses re-seated you can start the car and go for a drive, and being already warmed up you can drive the car hard if you wish (showing the ECU exactly how it should be fuelling!)

Don't be alarmed if the car is sluggish at first -- the ECU has been reset and is having to learn from scratch. If it's reset when the car is cold, the lack of performance and hesitation will be more noticeable, but will still pass after a good 10-15 minute journey where the throttle can be exercised.

NOTE: Resetting the ECU not only removes the existing fuelling map but also any error codes which were stored. This is handy for any one-off events which may have placed the ECU in 'safe mode' but should a problem still be evident then the ECU may instantly revert back to its conservative settings. If this is the case then the issue(s) should be addressed accordingly.

Cheers
KiwiMR2

[KiwiMR2]

Do you have a NA or Turbo MR2??

Cheers
KiwiMR2

[Rasker]

Do you have a NA or Turbo MR2??

Cheers
KiwiMR2

Thanks Kiwi, it's a N/A.

Originally removed the battery power from the car when I changed the fuel for 15 minutes, as someone suggested it would reset the ECU, then again someone else has mentioned the backup battery can sometimes have up to 48 hours charge on it, will give the fuse one a go.

Seems to be getting worse with each tank though, even though it doesn't seem to ping anymore.

[FST4RD]

260k's out of a tank???
I put $30 in my SW20 GT, which filled it up about half and managed to get bout 170k's out of it driving it conservativly.
I can definatley get well over 300k's out of a tank.....
Do the n/a's have a smaller tank than the turbos???

[Rasker]

260k's out of a tank???
I put $30 in my SW20 GT, which filled it up about half and managed to get bout 170k's out of it driving it conservativly.
I can definatley get well over 300k's out of a tank.....
Do the n/a's have a smaller tank than the turbos???

Use to get about 350 - 400Km out of the tank on 91, just started doing this since it's been using 96 Octane, did the battery ecu reset, might try Kiwi's method next though.

Think the NA is about a 40 Litre tank.

Going to try Kiwi's suggestion this weekend failing that it's going to a mechanic, either it needs a tune or something dodgy is going on.

[Mr Revhead]

resetting the ecu wil only make a difference if the ecu has a learning capability... and most dont. id be suprised if it makes any difference in any post 2000 toyota. they may have a knock sensor memory.....
they only way to tell for sure would be to do dyno runs with good diagnostic gear hooked up.

using fuel that fast it must be blowing a hell smoke cloud....
id say your problem is else where, not with the fuel. sw20s need at LEAST 96....

[CozmoNz]

im sure that 5sfe thing could take 91 lol.

But yes, general rule, always run the highest octane avilable.

oh and note on that *remove fuse thing*, make sure you use pliers or somethig, i dropped one lol, now its in the fuse box somewhere under the wiring X_X.

(good thing that they put spare fuses in the top of the fuse cover!)

[Rasker]

resetting the ecu wil only make a difference if the ecu has a learning capability... and most dont. id be suprised if it makes any difference in any post 2000 toyota. they may have a knock sensor memory.....
they only way to tell for sure would be to do dyno runs with good diagnostic gear hooked up.

using fuel that fast it must be blowing a hell smoke cloud....
id say your problem is else where, not with the fuel. sw20s need at LEAST 96....

wish it was then I could smoke all these aucklanders off the road

It was burning oil at one stage, haven't checked it since changing the octane and using a different oil.

Smokes at 5,000 revs but just slightly

Previous owners were using 91, wondered if that was because they were getting better milage from it :S this things a nightmare, anyone want to offer me something for it? hmm second thought it's my precious!

[Mr Revhead]

go to toyota, plug in the diagnostics and talk to them

[ChaosAD]

As for home tune. I bought a car that had a 'hometune' sticker on the cam cover stating when the cambelt was done and it was gutless.
Turns out they put the cam sprokets back on wrong.

[jjd]

go to toyota, plug in the diagnostics and talk to them

Or to your local mechanic or auto electrician who will be alot cheaper.

[Alex B]

go to toyota, plug in the diagnostics and talk to them

Or to your local mechanic or auto electrician who will be alot cheaper.

but wont have toyota diagnostics computer most likley

[1598cc]

Iv'e forgotten if it was ever proven BUT a lot of people reset the ecu so the car can re-learn.

ECU learns and adapts depending on factors like fuel quality, knocking, and climatic factors. Over a period of time, the ECU may develop a conservative fuelling map which robs the car of performance (or if a problem occurs, e.g. bad fuel or an engine safety scenario.) Although the ECU continually adapts, it's very slow at doing so and can be reset to speed up the process.

Preferably after a drive (and the car now at full operating temperature), park, remove the key, and wait a couple of minutes. In the engine bay is a fuse box -- remove the 7.5A ECU-B and 15A EFI fuses. In the front compartment (not the cabin), remove the 7.5A ECU-B fuse... and then wait for at least two minutes before replacing them. With the fuses re-seated you can start the car and go for a drive, and being already warmed up you can drive the car hard if you wish (showing the ECU exactly how it should be fuelling!)

Don't be alarmed if the car is sluggish at first -- the ECU has been reset and is having to learn from scratch. If it's reset when the car is cold, the lack of performance and hesitation will be more noticeable, but will still pass after a good 10-15 minute journey where the throttle can be exercised.

NOTE: Resetting the ECU not only removes the existing fuelling map but also any error codes which were stored. This is handy for any one-off events which may have placed the ECU in 'safe mode' but should a problem still be evident then the ECU may instantly revert back to its conservative settings. If this is the case then the issue(s) should be addressed accordingly.

Cheers
KiwiMR2

ive heard that in many places about ecus ; as well as with honda ecus. i dont believe they 'learn' anything. how can they, theyre just a old compter program and on WOT the ecu uses its built in fuel maps anyway

[Adamal]

As for the resetting trick... Is it, or is it not for cars that have coil ignition systems, where the firing timing is electronically controlled?