Fuel Trims maxing out.

turbo2086 · 12-06-2005

Okay I replaced my O2 sensor, and I used to get readings from rich to lean at idle. Like normal. Then I stopped getting them. I got my O2 replaced again by advanceauto for no charge. Still no readings at idle. I will not get readings tell around 2200 rpm. I'm sure its the warmer, but cant be the O2 sensor. Anyone off hand know what color wire it is, so I can possible test it, or find out whats going on. Since I have to start my car to warm up every morning now, my mpg is like 12. I can smell fuel coming out of my exhaust. My data logger says fuel trims are like 139.7% on L M and H.

CarPsyco84 · 12-07-2005

If your fuel trims are going that rich on the Medium and high trims, somthing else is wrong with the O2 senser or wire or somthing, cause I don't have a heater in my O2 either, and it only affects the Low trim, basicly idle, U have to be going like 30-40 steady for the Med. trim to get adjusted and like freeway for the high one to get adjusted...

turbo2086 · 12-07-2005

Yeah, I was reading up on that don dsmtuners. I'm to grab my multimeter, and going to check out my TPS, make sure its at, where vfaq has it.

turbo2086 · 12-31-2005

Oh hey guys going to give ya an update on my fuel trims... I tested all the sensors, including the o2, everything came out A okay.

I put a new fuel filter and PCV valve, just cause It hasnt been done since I owned the car...

Took the battery off while doing the fuel filter, so the ECU reseted. Once I started it up, the o2 cycled at idle, and fuel trims were all at 100%, like it should be. After about 5 days of daily driven, and some WOT pulls, my fuel trim low, and fuel trim high went back up to 139.8%. My fuel trim med is at at 122.8%

O2's used to cycle at idle, til today, which now reads .00v at idle. But if i just lightly tap the gas the o2s will read for a few seconds. So I know it must run rich at idle, so the EGTS are not high enough to get readings...

I guess I dont have a full understanding on fuel trims, and how I can keep them at 100%. In the mean time every few days I reset the ECU. I must say though my mpg has increased since doing all these resets, like 20mpg city, much better then what it used to be... Any feedback, or suggestions is appreciated about fuel trims and what not. Thanks My car is nearly stock, and does not have any fuel managment, fuel, or exhaust mods.

carltalon · 12-31-2005

when you installed the o2 sensor did it have a plug? Or did you wire it up to your old plug? sounds like you might have the wires mixed up if you rewired it.

turbo2086 · 12-31-2005

No I did get the one with plug.

turbo2086 · 01-02-2006

I did do that mod, where you take the lower honey comb off, and back the mafs screw out all the way. I'm thinking it may have something to do with that... I did order an un modified mafs off of ebay for cheap.

I put the screw up a few turns. After a few days my fuel trim med, and high are 104%. My fuel trim low is still 139%, however I'm getting 02 readings at idle.