running lean

[timopajala]

yep i know he is a good tuner. I´m gonna take the log first and go from there. Cable ordered but don´t know how long it takes to get here. My friend told me the same that its running like it should also, from start its rich and leans out from there.

[popo8]

...Stop guessing what's going on with the car and install a wideband.

[sweet-94z28]

If you think the car is running rich or lean, there is a way to confirm without a wideband, but your true air/fuel ratio without a wideband will be unknown. With Narrowband (factory type) O2 sensors, they have a voltage range of 0 mv to 1000 mv. when the air to fuel mixture is approximately 14.67:1 (stoichiometric ratio of gasoline, best burning ratio), the oxygen sensor will read out approximately 450-500 mv. With a narrowband sensor, at 15.5:1 air to fuel ratio (leaner), you will see O2 values in the 100-200 mv range. It switches away from 450 mv that quickly! Same goes for the rich side. Once you see values of 750-850, this means usually about a 13:1 air/fuel ratio.

If you have the ability to scan the computer and see what the oxygen sensors are reading, you will be able to generally see what the motor is doing. Under open loop, you will see numbers all over the place because the car cannot correct itself. If you have a big cam, you will likely see a leaner voltage at idle than actual because you are going to be moving more fresh air across the O2's due to the cam's overlap. I would only be concerned if you saw the car idling at a dead 100 MV or less when cold. That's a pretty bad lean condition and can cause other issues. Typically when cold you will see 500-950 mv because the car will run much richer under the warm up conditions open loop is set up to do. Another thing to consider is that too rich can be bad as well. If you get nothing but sooty, black clouds when the car is idling/revving/driving and it smells of raw fuel, that can be just as bad as a lean condition.

I agree with everyone else here... I would get a wideband. Just figured I would chime in and say that you can see which side of the spectrum you are on before being worried about what you are seeing.

[timopajala]

well i have the datac cable now and gonna record few data sessions and send them to the tuner and he will tune it properly etc. good write about the mv thing, didn´t know that one but i think the tuner knows that also. I´m gonna post the news as soon as the tuner gives me more info and so on.

[sweet-94z28]

We are all here to help everyone learn! I try to learn something new every day.

[timopajala]

We have tried to adjust the injector size several times and they are now at 23 i think and the injectors are 24lb. The car works ok, it just fluctuates the rps when cruising on low rps. When i whatch the rpm gauge it shoes 200-400rpm fluctuating. Is this still tuning issue or something else? I also have datamaster file on it from yesterday if someone knows how to read it? It only fluactuates when cruising between 1400-1800 after that theres no problems.

[timopajala]

http://www.filedropper.com/23lbtest

[timopajala]

i found a small fuel leak from my incoming line and also a vacuum leak so i´m gonna take new logs from my car. Also this could explain my huge gas consumption... like 220mails per 60l of gas and almost all of that was highway driving.