Fuel trim problem

[iron bird]

well ive been fighting with a hesitation problem, so i got a logger every thing seems fine numbers wise except for my fuel trim doesn't move it stays at 100%. My only thought is my ecu but im not so sensor savvy. Help Me

 

[habitatguy187]

They won't update until your car's sensors show certain readings. Basically the car needs to be in closed loop in order to update fuel trims.

The Essential Primer on the Diamond-Star Engine Control Units - Table of Contents

 

[iron bird]

so what your saying is my car could be stuck in open loop

 

[1gengsx]

It could be. Check your coolant temp on the logger it needs to be over 185 degrees. Also look to see if the o2 is switching. If it isn't it could be bad or its stuck rich or lean.

 

[iron bird]

coolant temp is between 199 and 206

 

[TenSecondSTi]

Check your battery voltage and charging system. It may be low to the point where your ECU resets.

Also a new o2 sensor would be a good idea. I just changed mine because it want's working now i got my fuel trims tuned in great. But need bigger injectors and a bigger turbo. and need to install my 2g maf.

 

[iron bird]

battery in this car is amazing voltages are never below 12.6 when off and it last for hours with the lights left on. Just put a new 02 sensor in last night but haven't got to go over anything yet.

ok new 02 sensor no help, i just realized to the cur will rev out fine at quarter throttle but full throttle it hits 3500 rpm and roes no where