ECMlink Lean Idle, but fuel trims correct - Why?

[ditchmagnet]

When I bought the car I was told that the car has PTE 880 injectors. After I did WOT tuning, it turns out that 550 scaling was the magic number. So I punched in +.180 deadtimes and my idle fuel trims are within +-5% but my wideband reading at idle is about 18:1!

Any idea what would cause this? I can't figure it out.

 

[PrimerPLus]

You probably have an exhaust leak. Run seafoam through your bov line and watch for white smoke.

 

[ditchmagnet]

What BOV line? The leak would cause a lean read on WOT as well in that case right?

 

[PrimerPLus]

The one that comes from your intake manifold that goes to your BOV

 

[YZFR1]

It could be also reading lean when you don't have complete combustion, meaning more unburned fuel. Since, oxygen sensor is just a dummy device that only cares about oxygen molecules.

 

[PrimerPLus]

What BOV line? The leak would cause a lean read on WOT as well in that case right?

Yes it will cause wrong readings. They may seem normal but the real results will be inaccurate. Make sure to do the test where you can see fine and able to get down and look under your car. Check where all the exhaust components bolt together including exhaust manifold, turbo, o2 housing down pipe all the way through to the end. The most important places are pre wideband sensor and o2 sensor.

 

[ditchmagnet]

Will this be safe for my wideband, or will it kill the wideband?

 

[Stapl3]

Be sure the wideband sensor is properly open air calibrated.

Be sure there are no boost leaks.

Post a log.

 

[ditchmagnet]

I know my TB has a boost leak, and it is an AEM UEGO wideband, so I don't think you can calibrate it.

I will post a log later today.

 

[ditchmagnet]

Still haven't made a log, but I did finally do the exhaust leak test/seafoam treatment.

Ya, BIG leak on both sides of the O2 housing. Guess I need new gaskets there. So how off do you think this is throwing my WOT readings? I would think it would affect the reading a little less since there is just so much more exhaust coming through at that time.

So I am guessing that my leaking TB (and maybe still others after I get that fixed) is causing a lean idle, and the exhaust leaking is causing my wideband to have an even leaner reading at idle.