Adjusting shift points and TC lockup - Fuel Economy, Hypermiling, EcoModding News and Forum

mechman600 · 03-29-2010, 03:26 AM

Yes, I am stuck with an automatic because my wife doesn't want to be bothered to learn a manual. I tried once with my old Echo, but let's say it was a less than enjoyable experience for everyone, especially the car.

It's an '06 Matrix, and the economy is awful, mostly because my wife uses the car the most and doesn't want to be bothered with changing her driving style. So I guess that leaves me with focusing on the 'modding as opposed to the 'miling.

The worst part about this car is the auto transmission. It's a slush-box, to say the least. My '01 Honda auto was more "positive" feeling. Basically, it locked up the TC whenever it had the chance. At a 25 km/h slow cruise, it would lock up in 3rd, and at 40 km/h it would lock up in 4th (OD). It would get 44 mpg (Imp) in mixed city/hwy without much effort.

The Matrix will not lock up in 3rd, unless you hold it in 3rd or if it is in "smart hill climb" mode, and then it will only lock up at 75 km/h. In 4th it locks up at exactly 60 km/h. Anything below 60 km/h, it remains unlocked. I believe this is the reason for crappy mileage. Sure, it is heavier than the Civic, but still, 32-33 mph (Imp) is pretty bad.

The question: is there diagnostic software/devices available to tamper with the shift points and lock up logic? Any Toyota techs on this forum? Does a Toyota dealership have the capability, as reluctant as they would be to do so, do adjust such things?

The only other thing I am considering is an automatic alternator cut that will be normally "open" and "close" when the brake switch is activated through some relays and whatnot. Sort of an ultra cheap, poor man's hybrid of sorts.

Daox · 03-29-2010, 08:16 AM

You can do it, but you'll need to make your own electronic device that spoofs the transmission ECU into thinking you're going faster than you are and are giving it less throttle than you are.

mechman600 · 03-29-2010, 10:09 AM

So I guess there are no programmable parameters that you can change, like in a heavy duty truck?

Daox · 03-29-2010, 10:14 AM

Nope. Its programmed to be good for everyone, and great for none.

micondie · 03-29-2010, 01:48 PM

A factory shop manual might give you some clues about which signals you could tweak to fool your transmission but my own research on the subject for my Caravan lead me to believe that in my case such tweaks would also have a negative effect on driveability, emissions, and mileage. You might want to check into a performance valve body for your transmission (if available) to firm up your shifts and maybe offer some manual control. If your manual leads you to think that electronic tweaks are possible try this website for info: Browser Warning

comptiger5000 · 03-29-2010, 04:44 PM

If it's a computer controlled transmission, you might be able to have the computer modified to adjust some of the shifting.

mechman600 · 03-29-2010, 11:35 PM

Quote:

Originally Posted by micondie

...try this website for info: Browser Warning

Thanks for the link. A great article. Gives me a few ideas. However, I can't see changing intake temp, EGR flow, MAF and O2 sensor values providing much more than a ~5% gain. I've read that leaning from 14.7:1 to 15.7:1 is the most gain you can get, and that's only about 3-5%. Any leaner and it starts going the other way, not to mention NOX levels going through the roof. But I guess every bit helps, hey?

MaxHedrm · 03-30-2010, 01:07 AM

Look into performance chip companies. I know in the VW world there are always chips for the trans as well as the ECU.

mechman600 · 03-30-2010, 01:21 AM

Ok. I just had a good hard look at the Toyota shop manual, namely, the electronic transmission controls. It is controlled by the engine ECU, and there are 4 outputs: three shift solenoids and a TC lockup.

It would be nice to come up with an electronic gizmo that overrides the TC lockup output from the ECU. Here's what I'm thinking, using signals from the TPS and VSS:
If vehicle speed is above ~25 km/h and throttle position is below ~25%, my "device" triggers a relay that sends power to the TC lockup. If neither condition is met, the transmission acts normally.

Roger Jolley · 03-30-2010, 02:12 AM

Quote:

Originally Posted by mechman600

Ok. I just had a good hard look at the Toyota shop manual, namely, the electronic transmission controls. It is controlled by the engine ECU, and there are 4 outputs: three shift solenoids and a TC lockup.
It would be nice to come up with an electronic gizmo that overrides the TC lockup output from the ECU. Here's what I'm thinking, using signals from the TPS and VSS:
If vehicle speed is above ~25 km/h and throttle position is below ~25%, my "device" triggers a relay that sends power to the TC lockup. If neither condition is met, the transmission acts normally.

I like that idea. A transistor controlled device, I should think.