germanshepherd

say what you want, it worked for me. I went into this thinking it was NOT going to work. I am not talking about changes in wide open throttle etc, just the elimination of lag time. and to throw your placebo affect out the window, I did this to my wifes Acura without her even knowing and the first time she drove it she said her car felt peppier. I never told her what I was going to do, she never knew I did this to my truck. For the placebo affect to work one has to be aware of what was done. She had no clue and she immediately could tell the difference.

what I find to be non-sense is when someone dismisses everyone elses experiences. Nice way to put people down and their education and no, I was not home schooled. If you have nothing nice to say why say anything at all. Typical forum..
Good day Sir.

screamineagle

So....Since this "mod" doesn't work for everyone, it "proves" that it's bogus? Seems it has worked for some and calling people stupid "in a roundabout way" is a little uncalled for don't you think?

Mod (Ret.)

With fuel injected vehicles, a gas pedal does not exist anymore. The pedal on the right no longer connects to a cable that runs out to a carb to squirt some fuel down the carbs "throat" into the intake manifold. Instead, that pedal has a potentiometer (a switch that varies resistance based on how much it is rotated), refered to as a "drive by wire" system.

This potentiometer sends a variable resistance reading to the PCM (powertrain control module; some manufacurers refer to it as an ECU - engine control module) that is used to determine how far the right pedal has been pressed, and in turn, is used to operate the throttle body's valve, to open (or close) it to allow air flow into the intake manifold, which is mixed with the fuel from the fuel injectors at the cylinders. The air to fuel mixture is controlled by "mapping", a database file of sorts stored in the PCM. The right pedal is pressed, the variable resistance is determined, and the throttle body is opened accordingly, and air is mixed with the fuel.

This switch/potentiometer at the right pedal can be calibrated as described in older drive by wire vehicles by turning the key to on (don't start the engine), and pressing the right pedal down slowly, so the PCM can "read" the potentiometers positions as the pedal is being slowly pressed, and store its relative position as resistance during this cycle.

I've not heard of this calibration procedure being used to produce MPG gains, but rather to help eliminate any lag in the right pedal during acceleration.

Its not any type of magical fix for those who have a poor running engine. It can however, eliminate some lag in early drive by wire systems. As MGD mentions, most newer "drive by wire" systems are self learning and self adjusting, so this procedure may be moot on the newer vehicles.

techrep

iTrader: (1)

Well stated Bucko...

PerryB

Bucko is right on the money. The recal. may change the throttle position relative to pedal position and may make the vehicle seem more responsive, but it will probably unlearn fairly quickly and return to its original calibration. Fuel mileage will not be affected. To get better fuel economy you have to do the cruise control trick......

Summers22

iTrader: (2)

The only thing it does is eliminate lag, and it is unlearned within a month or so of normal driving. Time to do it again on my wives Expedition.