97 zj 4.6L running lean

[sly-jeeper]

96 block .030 over
Mopar 229 cam
Keith black ic944's
Scat crank
24Lb ford injectors

This thing is running stupid lean when the 02 sensor is plugged in and runs better but still half ass with it unplugged, fuel pressure is 45 psi and holds it to red line. I've basically swapped every sensor and I'm about ready to swap the harness and computer

[jeepxj3]

Why would you run it with the O2 sensor unplugged?
Maybe it needs some run time to adjust and 'learn' to set the AFR. Check your short and long term trim values.

[SilverXJ]

What are the numbers you are seeing?

[sly-jeeper]

I haven't hooked up my wideband yet but I can smell its crazy lean glows the header orange quick and idles rough + backfires....until I unplug the 02 then smoothes out but still glows header and is down on power. All of this started before the stroker swap so its definitely an electronic problem

[SilverXJ]

I would check the harness very thoroughly for anything grounding out or the like. Have you replaced the upstream O2 sensor?

[sly-jeeper]

Yea I replaced the upstream two times one NTK sensor and one bosch. The downstream sensor is unhooked and has been unhooked for over a year before this problem shook its head. I'm gonna check out the harness very carefully and educate myself more on how the 02 sensor works and what I can do with my dvom to diagnos it.

[sly-jeeper]

Hmmm. Got out my obd 2 scanner and with the sensor plugged in it reads 0 volts all the time unplugged it reads 1 volt...so its definitely on that circut

[sly-jeeper]

Figured it out, pos Bosch sensor and the pins on the harness were not making good contact

[jeepxj3]

Upstream or downstream sensors or both? Dielectric grease.

I've had best luck with NTK O2 sensors.

[sly-jeeper]

I soldered it into the harness