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General Wideband vs Narrowband conflicting readings

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roadtrip_69

15+ Year Contributor
38
3
Apr 18, 2008
Cincinnati, Ohio
A little backstory, a few weeks ago i blew a coolant line in 95 degree temps and before I knew it I over heated to the point of the head warping. Ripped it all apart, got it resurfaced, put everything back together. Replaced most hoses, vacuum lines, all seals and gaskets, radiator, water pump, thermostat etc etc. Started her up and ran fine, idled normally but with some lifter tick(normal after such a job as far as I know and they have since quieted down considerably).

Took it for a test drive though and not even 1/4 mile down the road. It started acting very strange, and wanting to die. Figured I blew a intake hose or something. Drove home. Did a boost leak test, as I could HEAR leaking air(vacuum actually)from around the throttlebody area. Turned out it was 80 percent the 4th cylinder fuel injector seal. And the TB gaskets. I fixed them both, pressurized to 25 PSI. Still have a minor leak coming from the throttle body shaft seals. Have those on order. But figure those have probably been leaking for a while. Was a very small leak. Anyways so put it all back together. Starts up fine, runs fine more or less. Though I've been taking it easy because of the following.

Now the actual issue

After sealing up those issues, now I am running super RICH according to my Wideband (9.0-9.5). But super lean according to the Narrowband in closed loop mode.(Maxing out fuel trims P0170 code as well) So narrowband is telling the ECU to pump more fuel into the intake but wideband shows its getting more than it needs? Which is the defective part? I don't want to re-tune (ecuflash) based on bad sensory information.
Before the head issue, at idle the wideband would always read leanish, but would move around. (I'm guessing now due to the vacuum leaks at idle sucking in unmetered air?) And I have the wideband in the factory downstream location so i know its a little less accurate there and delayed than if it was in the turbo elbow. But they both can't be right, but only one controls the ECU. Is the narrowband just shot?

If it was the other way around, the narrowband was reading rich, and the wideband lean that could be explained by a leak between the two in the exhaust. (which would be a big leak) But extra fuel isn't going to bypass the narrowband and make it all the way to the wideband is it?? Am i just over thinking this? LOL

Any help would be appreciated! Thanks in Advance!
 
I'd trust the wideband after a free air calibration. If you are running Link, simulate NB and see how she reacts.
If you're not using link, do a free air calibration of the WB sensor so you can trust it. Most max out at 7ish so IDT its reading FULL rich just REALLY rich and thats bad. Any black smoke from over fueling?
 
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