Instant MPG
- Thread starter Be2lose
- Start date
Which is true.....unless said "engine braking" "engages".The TB is the greatest point of restriction, but it doesn't dictate the air/fuel consumption, the PCM does that, and if you were at 0% throttle, the TB wouldn't even be open, the only air coming through would be through the IAC vavle, so the TB isn't even in the equation. The TB doesn't open UNLESS you do it manually.
Right...my explanation must have been flawed.
But just to hassle you J
, did you know that there is another location where air is sucked in when the throttle is closed? There is a 1/8" hole that goes through the center of the TB casting. It goes all the way through. I know because I've had to clean out all the carbon from it in the past.Right...my explanation must have been flawed.
But just to hassle you J
Lol I like to be hassled, than proven wrong or right! I wouldn't doubt you there, most cars have some sort of random port going through the TB, some of them don't even go straight through, all squiggly and stuff, haha. I know our cars won't idle with a fully closed IAC but I wonder if the hole has something to do with smoothing out the idle? Maybe the IAC isn't very "precise" and the hole helps compensate? Who knows.....you know more about it than me, since you've had to clean it out, hah.
The PCM is programmed to work with a certain injector flow rate. Based on this, along with the injector pulsewidth (i.e. how long it's opening them open), it determines the rate of fuel consumption. The trip computer uses this along with the vehicle speed sensor signal to calculate gas mileage.
Have you bumped up the fuel pressure and/or installed higher-flowing injectors? If so, have you reprogrammed the computer accordingly?
For example if the stock injectors are 20# and you replace them with 30#, the computer won't have to hold them open as long to get the right amount of gas into the engine. And if it's still programmed for 20# injectors, it'll think the engine is using a lot less fuel than it really is.
Have you bumped up the fuel pressure and/or installed higher-flowing injectors? If so, have you reprogrammed the computer accordingly?
For example if the stock injectors are 20# and you replace them with 30#, the computer won't have to hold them open as long to get the right amount of gas into the engine. And if it's still programmed for 20# injectors, it'll think the engine is using a lot less fuel than it really is.
Just jumping back a little. I did notice it ( it feels like a down shift) the feul shuts of at about 30mph( normal downshift to 2nd) 2100rpm, when i dropped below 30mph it would kick back in and mpg would drop back to the 50's.
Today I had a 3 mile hill to test this on.
Very cool.
Roadboss
On Work Release
Yes I am running 60 lb injectors, along with the KB Boost a Pump and Focus Fuel Pump. Yes this setup has been reprogramed and works flawlessly on the drivability issues. My only wish is to get my DTE and fuel mileage readings correct on the display.
This is new to me too! My first experience was when I just installed my trans/stall converter and went on a 4 hour trip to Reno. I had probably 20 miles of hills to freak out on, haha, I didn't know wth was going on, and I was running no mufflers so it was super loud.
Its cool to find out that they programmed even more into the PCM than you imagined, now I notice it on every car! Lol!