Max lean low fuel trim.

[2.4 turbo Hyped]

This has been going on for some time now. My low fuel trim is maxed out lean and I dont have anymore adjustment on my idle knob on my maft. My low fuel trim is at 140%. The o2 trim cycles at 167% or just goes into closed loop cause it cant correct enough for it. My fuel trims are as follows 140-103-88:l-m-h. Now If I turn the ac on the low fuel trim will trim up to around 100% where its supposed to be. The only thing I can figure is that with the 2.4 motor the stock ecu fuel maps wont make up for the flow. While cruising my trims bounce around 100% on the o2 trim. This is a strange problem that I would like to correct. Someone out there has the answer to this problem. Before the 2.4 the fuel trims were fine.

[kyle h.]

change the o2 sensor, the heating element in it is probably shot.

[2.4 turbo Hyped]

This will be the 5th o2 sensor since I have owned the car. I will give it a try though.

[Sephroth57]

www.machv.com has o2 sensors that are made to be used with race gas, might want to pay the extra money for a really sturdy o2

[Darksyne]

Originally Posted by 2.4 turbo Hyped

This has been going on for some time now. My low fuel trim is maxed out lean and I dont have anymore adjustment on my idle knob on my maft. My low fuel trim is at 140%. The o2 trim cycles at 167% or just goes into closed loop cause it cant correct enough for it. My fuel trims are as follows 140-103-88:l-m-h. Now If I turn the ac on the low fuel trim will trim up to around 100% where its supposed to be. The only thing I can figure is that with the 2.4 motor the stock ecu fuel maps wont make up for the flow. While cruising my trims bounce around 100% on the o2 trim. This is a strange problem that I would like to correct. Someone out there has the answer to this problem. Before the 2.4 the fuel trims were fine.

I'm having the same issue, at idle the low fuel trims will go to 139% and stay there. However if I raise the RPM's to about 1500-2000 then the low fuel trims will drop to around 100%. If I idle for a long period of time then the engine loads up with all the extra fuel.

Did you ever get this issue resolved 2.4?

[steve]

Originally Posted by Darksyne

Did you ever get this issue resolved 2.4?

If I remember correctly a large part of his problem was injector deadtime related.

Steve

[2.4 turbo Hyped]

I fixed it. It had nothing to do with injector deadtime. It was half of my throttle body gasket missing that caused all of the problems from crappy fuel mileage to erratic pulls. Do a boost leak test and Im sure you will find the same issue as I did.

[Darksyne]

Originally Posted by 2.4 turbo Hyped

I fixed it. It had nothing to do with injector deadtime. It was half of my throttle body gasket missing that caused all of the problems from crappy fuel mileage to erratic pulls. Do a boost leak test and Im sure you will find the same issue as I did.

Yeah I just did one a few weekends ago, I guess the search continues...

Thanks for the update!

[steve]

Originally Posted by 2.4 turbo Hyped

It had nothing to do with injector deadtime.

Sorry, must have confused you with somebody else.

Steve

[92redman]

Originally Posted by Darksyne

Yeah I just did one a few weekends ago, I guess the search continues...

Thanks for the update!

Have you figured out your problem yet?

[Darksyne]

Originally Posted by 92redman

Have you figured out your problem yet?

Yes, I pulled the upper heat shield and two of the turbo bolts were loose. After I tightened them back to spec my low fuel trim settled back down to 109%

[92redman]

So you were possibly sucking in fresh air through an exhuast leak at idle? That may be my problem becuase one turbo bolt is broken, a couple manifold studs are broken, and they are original gaskets.