GuNmETaL_Si

WHAT DOES THE O2 SENSOR HAVE TO DO WITH GAS CONSUMPTION? ISNT THE O2 SENSOR IN THE CATALYTIC CONVERTER? or is there ANOTHER o2 sensor that youre talking about?

babs

I'm with Tmac on this one... a fuel injector cleaning should if not solve the problem, help it.

bbarbulo

iTrader: (2)

Fuel injector cleaning will do nothing to help stop gas consumption. Depending on how bad it is, it's clearly an issue of misreadings from the sensors and emissions equipment. Does your car exhaust smell like gas more than usual? Dirty injectors give poor atomization, and less fuel than normal, not more.

bbarbulo

iTrader: (2)

Here is something about a related question someone PM'd me.

There are many sensors that determine gas consumption. The MAP sensor determins load and air flow, the air temp sensor determines intake air temp, and the O2 sensors determine the end result of the input (air to fuel), the throttle position sensor determines how fast you are trying to go, and the vehicle speed sensor determines what speed you are already travelling at. In closed loop mode the ECU does everything based on the best guess from most of these sensors. The O2 sensor is useless until it reaches 600 degreed F, at which time it becomes effective, and then the ECU can go into open loop operation. Open loop is the ECU dynamically adjusting the mixture on the fly, based on feedback from the O2 circuit. The O2 sensor then returns info back to the ECU about how good the first estimate was with respect to air/fuel ratio, and the ECU adjusts the fueling according to new input. If WOT throttle is sensed by the VSS, then the ECU leans it out and watches the O2 sensor and knock sensors. If the knock sensor detects knock, the ECU will change the ignition maps. This is just a short version of how fuel injection basically works, but there is more to it than just these things. Basically, this is where the nitty-gritty tuning happens.

Hope that helps....

By the way, on an OBDII car, most of the time if you put a test pipe in, it should have an O2 bung welded in, but I have seen cases where the ECU recognizes an ineffective catalytic converter based on the comparison of the values of each of the O2 sensors. This results in a CEL, which can now only be permanently fixed either by replacing the cat or doing a wiring mod. The wiring mod can be of two types...a resistor hooked up the the second O2 signal lead, or placing an O2 sensor simulator in line with the ECU instead of the actual O2 sensor. The simulator will provide correct values for the ECU to read, and will fool the ECU into thinking there is a functional O2 sensor hooked up that is reading the correct values. This is not a good mod for a street driven car...cars run much better on the street with the correct modifications and emission equipement in place.

GuNmETaL_Si

good point bbarbulo...its the sensors and stuff that tell ecu how much fuel to use...so what ways are there of fooling the ecu into using more/less fuel...although doing so may not be good...

fuel pressure regulator?
air/fuel computer?

bbarbulo

iTrader: (2)

By the way, on an OBDII car, most of the time if you put a test pipe in, it should have an O2 bung welded in, but I have seen cases where the ECU recognizes an ineffective catalytic converter based on the comparison of the values of each of the O2 sensors. This results in a CEL, which can now only be permanently fixed either by replacing the cat or doing a wiring mod. The wiring mod can be of two types...a resistor hooked up the the second O2 signal lead, or placing an O2 sensor simulator in line with the ECU instead of the actual O2 sensor. The simulator will provide correct values for the ECU to read, and will fool the ECU into thinking there is a functional O2 sensor hooked up that is reading the correct values. This is not a good mod for a street driven car...cars run much better on the street with the correct modifications and emission equipement in place.

This part of the prev post answers the ECU side of things...electronics.

The air/fuel controllers out there are usually for boosted applications to add fuel under boost.

Fuel pressure regulator can be used in some applications, but usually it is not necessary for an NA car that has not been really tuned with cams, cam gears, port and polish, exhaust intake, etc. Lower pressure = less fuel = detontation = melted pistons/blown head gaskets, or higher fuel pressure = more fuel = rich burn = lower power output = cooler combustion.

bbarbulo

iTrader: (2)

You asked about an O2 sensor, here is a cheap but good one. Denso is the supplier for a lot or Japanese co's.

http://cgi.ebay.com/ebaymotors/ws/eB...tem=1876432102

imported_Duge

it can be the o2 sensor, however if you aren't getting an engine light, then it could be something else, if the o2 sensor ***** off, then the EL comes on