Shifting Tactics

[rh77]

I rented a Toyota Matrix (Pontiac Vibe) on a few occasions and found that from a cold start, under heavy throttle, the ECU won't let the RPMs go higher than around 3000 RPM until the coolant temp is high enough -- perhaps an engine saving or emissions feature. I think the ECU is pretty complicated and un-traditional and may apply to the Scion line (similar engine probably). Maybe the computer doesn't react to closed throttle as expected.

I need to get a ScanGuage...injection pulsation is good info to have.

RH77

[JanGeo]

Not official just a guess - any way you could check the exhost for fuel use - oxy sensor feedback? to see if gas is being injected?? Heat rise of a cold engine may idicate something also. Fuel pump current?

Just thought of another test - climbing hills - going fast and going slow should yield the same mpg unless the engine has a sweet spot. Maybe a great way to test power levels without going too fast to eliminate air drag factors. Going up hill with a cold engine really gets the engine temp up quickly - keep rpm low to increase heat absorbsion inside the cylinders.

Coasting in/out of gear - if you have to time a light then slowing down sooner will preserve more speed when getting to the light green. Also stopping on a down hill with a light - better to stop higher up on the hill if you can and use the hill to speed up when the light turns green. Stop signs don't work with this technique.

[MetroMPG]

Originally Posted by rh77

I need to get a ScanGuage...injection pulsation is good info to have.

it actually doesn't show that directly (though it must USE that info for the instant/avg MPG calcs). it doesn't show fuel trim either.

[rh77]

Originally Posted by MetroMPG

it actually doesn't show that directly (though it must USE that info for the instant/avg MPG calcs). it doesn't show fuel trim either.

I wonder if it's possible to get a "Y" OBD-II splitter, so I can use my data logger to get fuel trim, etc. and plug the ScanGuage into the other port.

RH77

[Matt Timion]

Originally Posted by rh77

I wonder if it's possible to get a "Y" OBD-II splitter, so I can use my data logger to get fuel trim, etc. and plug the ScanGuage into the other port.

RH77

I bet that you could make one really easily. I also bet that you could contact the guys at www.rywire.com to get one made for you.

[SVOboy]

I rented a Toyota Matrix (Pontiac Vibe) on a few occasions and found that from a cold start, under heavy throttle, the ECU won't let the RPMs go higher than around 3000 RPM until the coolant temp is high enough -- perhaps an engine saving or emissions feature. I think the ECU is pretty complicated and un-traditional and may apply to the Scion line (similar engine probably). Maybe the computer doesn't react to closed throttle as expected.

Similarly, my friend's 01 civic sets a rev limit based on certain factors. For example, I can't rev it up in park, or with the brake on, so there's no possibility to peeling out unless I neutral bomb the thing, but I'd feel bad doing that to someone else cars,