Help to Reset or Restart original computer value

[orangel]

Hi.

I have a problem with my sunfire 2002 2.2L (55000Km).

months back I made a injectors cleaning, after the cleaning the consumption of gasoline increase.

the gasoline consumption before the cleaning was of 11, 11,5 Km/L, after the cleaning low between 8,5 to 10 km/L

I change the air filter, gas filter, spark plugs , recalibrate spark plugs but the gasoline consumption continuous same (high).

is possible to restart the original values of the computer if I disconnect the battery?

[alfonz]

Disconnect the positive (red) wire from the battery for a min to be safe, and reconnect it. Then start the car and let it idle for 15 min. Don't touch the gas, this will let the computer reset itself and recalibrate.

[hotbug1776]

that doesn't work on the newer cars, they have a "held" memory. it's like your TV, it can sit for a couple days and not lose the channels. same thing with the newer computers. some code readers can flash that memory back to factory.

Many other issues will give poor gas mileage. things like tire pressure, fuel pump, car weight, wheel bearings, just to name a few.

are you getting proper fuel pressure? are your tires at proper pressure? have you added anything to the car (stereo, stuff in the trunk)? any unusual noises or alignment issues as of late? how's your idle speed?

[orangel]

Originally Posted by hotbug1776

that doesn't work on the newer cars, they have a "held" memory. it's like your TV, it can sit for a couple days and not lose the channels. same thing with the newer computers. some code readers can flash that memory back to factory.

Many other issues will give poor gas mileage. things like tire pressure, fuel pump, car weight, wheel bearings, just to name a few.

are you getting proper fuel pressure? are your tires at proper pressure? have you added anything to the car (stereo, stuff in the trunk)? any unusual noises or alignment issues as of late? how's your idle speed?

I have verified pressure of tires, the car it's in the same conditions that before the cleaning injectors

as I can verify the pressure of the gasoline pump?, exists some way to verify or to give maintenance to the censors?

is strange because some times I get to obtain the original consumption and when the tank this in the reserve the car is more power and more light

[hotbug1776]

fuel pump pressure is done with a pressure gage attached to the pressure side of the fuel line, usually a fitting needs to be put on to allow the gage to be hooked up. some cars have fittings on the fuel rail. A dealer or just about any mechanic can test your fuel pressure.

to be safe please check your O2 sensors, while you didn't mention a check engine light, one of the O2 sensors may be sending a signal to run the car with a rich fuel mixture. other than that, I would take it in and have a mechanic look into your engine sensors, then have them reset the computer while you are there.

[orangel]

Originally Posted by hotbug1776

fuel pump pressure is done with a pressure gage attached to the pressure side of the fuel line, usually a fitting needs to be put on to allow the gage to be hooked up. some cars have fittings on the fuel rail. A dealer or just about any mechanic can test your fuel pressure.

to be safe please check your O2 sensors, while you didn't mention a check engine light, one of the O2 sensors may be sending a signal to run the car with a rich fuel mixture. other than that, I would take it in and have a mechanic look into your engine sensors, then have them reset the computer while you are there.

this procedure works?

step 1. turn the key to the "ON" posistion./ step 2. disconnect the positive post of the battery./ step 3. leave terminal off for 5 to 10 minutes./ step 4. turn key to "OFF" posistion./ and finally step 5. reconnect battery

[hotbug1776]

Sometimes it takes over an hour, some take over 3 to reset.

The scan tool is the only way to completely reset the computer. Unplugging the battery holds on to the learned fuel tables and in-memory dtc's. Pulling the battery resets the continuous and non-continous test results, resulting in the MIL to go away, and the computer to need to go back through the testing cycle.

in other words, even if you pull the battery it will hold the information overnight in some cases. and it will never let go of what it learned, it will just have to re-test to confirm what it has for data.