[Tominator]

http://www.fordfuelinjection.com/?p=80

I'm hoping to get my Ranger on a Dyno this spring and had not thought about the computer relearning after every change in timing or fuel map between pulls. A pulley change on a supercharger or even a modified air intake would seem to need the same procedure to let the computer relearn.

This all makes sense once you understand how EFI works, but I've not seen this issue addressed before.

For those that have been on a dyno the question is did you/they follow this procedure?

[BlueStreak03]

Most of the time when someone takes their vehicle to a dyno the car doesn't sit long enough for the coolant and oil temps to drop. The ECU does not have to be cleared if you are just doing a dyno for numbers. This actually could cause more harm than good due to the readiness parameters not being set and the ECU relearning how to make the car run. I don't know who this pompous terd is that claims only a few people in the world understand how EFI works and even fewer know how to run a dyno, but he's got an ego the size of Alaska.

[mustanghelper]

Lets see, How long will it take the computer to adjust for higher timing and fuel pressure? 5 minutes? i really don't think so.
I'm pretty sure you need to drive the car for about 20 miles or so before the computer learns how to deal with it. Clearing the computer will only put it back to stock program. with has 10 degrees of timing and 39 lb of fuel pressure.

What do you think?

[Tominator]

I think the article was meant to point out that when a chip or programmer is used any further modifications would require a computer reset.

Otherwise the old information stored in the ECM would not let the computer take advantage of said modification.

It also points out the need to be 100% sure the car is operating at the required temperature.

When you use a dyno to tune a car rather than just get a number several pulls are required. You are using science to tune the car and that requires duplicating the environment as nearly as possible between pulls and only the installed tune being the variable.

Starting the pull with even a 20* difference will throw the numbers way off.

[mustanghelper]

So if the computer is reset before a chip make sure you warm it up first. That makes perfect scene...
Otherwise you adjust the timing ,and fuel with a wb,o2 sensor and use the pulls to get the best of three.