ECT POWER MPG increase.. why?

Mileage increase could be due to the tranny shifting gears at the most efficient point, the engine tends to work harder if the revs and shift points aren't optimal. I did notice a similar issue on my old Jimmy when I quit using the overdrive around town, my mileage actually increased a bit. I gotta fill up with gas today, maybe I'll try a tankful with the ECT on although increases may just be due to not getting your foot into it so much as you accelerate up to cruising speed.

 

sub'd Gotta try this out!

 

You know when I bought my 96 a few months back I had the button depressed for a few tanks and I was getting better mileage than I am now. I'll have to test this theory on the next tank.

 

I am gonna jump in and say, this is the answer.

ECT button on, should be less mileage in a perfect world
ECT off, should be better mileage in a perfect world

this 'perfect world' is driving with your foot in econo mode as well.

I have 14 years of ECT on and off experience in a 4runner, with
10 years scangauged, and overall, there is a smidge better MPG with ECT off

I use ECT on a lot though, because I am on the highway a lot and I like
it to downshift sooner as I want to pass and filter myself into the
traffic patterns...with ECT off it is a dog, and I end up matting it harder
to blend into traffic. This takes a little off the MPG

So, it is still 'how you use it' but the ECU program and shift points, -on paper- dictate better
MPG with ECT off but only if you basically have identical pedal pressure and
driving pattern.

 

subd

 

Depends on driving style if it will work or not. If ECT power is off and you are an agressive driver it will hold a lower RPM/higher gear with more gas, but not going as fast/quick as if you were in a lower gear. Now if grandma were to use ECT power it will not be effective. Because it will a lower gear for no reason.

 

I was experimenting with this today (didn't see this thread prior) and my Ultra Gauge would report a 3-4 real time mpg increase with the button activated. This was traveling o/a 55 mph on flat highway. I know the Ultra Gauge isn't an science but the increase did catch my eye. Thanks.

 

Still makes me think the ECT switch could be reversed in some trucks. I've also noticed some quirkyness with the 4x4 and diff lock lights being wrong, so maybe there are a few gremlins in the system.

 

I've been driving with ECT on since i got the truck 17 months ago.. I just liked the shift points better with it on. I'll have to test mpg with it off and report back.

 

Maybe "ECT on" also advances the ignition timing slightly? That could produce better MPGs.

 

*ECT

 

I used to get better mpg with the button on too in my 01. There are probably many different reasons including driving habits that makes this not true for everyone but RPM are really not the biggest determining factor in fuel consumption. Manifold pressure, aka the load on the engine really determines fuel burn. Those of you taco owners with any aviation experience with piston engine aircraft and constant speed propellers (aka always the same RPM) will understand this.
Basically if your in too high of gear all the time and the engine is struggling, it will decrease fuel economy just as much or more, and is harder on the engine, than running in too low of gear with too high of RPM. People lugging their stick shifts with some illusion of getting better fuel economy are usually wrong. Some people manage to baby the accelerator in too high of gear and the engine electronics are really good at compensating allowing them to squeeze out a few mpg, but that's besides the point.
The engines have a happy RPM range, this is where they are designed to run and will get the best fuel economy usually. I believe the ECT button allows the truck to stay in the happy zone more easily when driving on the highway. The engine can really struggle to accelerate when the torque converter is locked.

 

I think it seems to be that for around town driving and uphill you should drive with it on, but for highway and long drives it should be off. Just my opinion...

 

seems like a good conjecture to me.

 

Mine sometimes goes up with it on. I use it on windy trips and it helps hold in gears better up hills.

 

Manifold pressure equivalent to vacuum pressure if i'm reading your post right EDJY and the same way (that show on SPEED network i think) eek'd a few more MPG's out of their Dodge pickup by installing a vacuum gauge and 'coaching' themselves to keep the vacuum in the good zone thus not just flooding the intake stroke with excess fuel.

Also, i agree that the truck is happier, peppier, and i feel (and will verify for myself) that a slight MPG gain is had with it activated.

 

I thought that was me for a sec

 

I tested the ECT today on my drive in to work (25 miles, mixed hills and highway) Using my UG I showed ZERO difference in instant MPG between ECT off/on, but the truck just felt "better" with ECT on. More responsive and smoother shifts in every situation.

I'l just leave it on..

 

some dude in japan knows the logic behind this stupid button and is probably laughing at this thread..

 

lol he probably is but im still gonna try it out

originally when i got the truck i thought it was for just when you were towing or carrying a heavy load and needed the truck to hold onto the gears longer ...

BUT now i know its a fuel saver button