04 Mustang GT O2 Issues

For anything machine shop / speed shop or engine specific. More technical than the range but not quite tuning specific.
Sidyrr
Posts: 12
Joined: 2021 Mar 03, 17:48
Location: Oklahoma
Vehicle Information: 2004 Mustang GT
Vortech Supercharger 6psi, BBK 78mm TB
Moates QH
wbo2-LC2

04 Mustang GT O2 Issues

Unread post by Sidyrr »

Hope this is the right place to post this. I've been having some issues with my O2 readings on an 04 GT. The passenger side O2 likes to camp out around 0.0v and fluctuates just enough to not cause an O2 stuck lean error code. The driver's side O2 is a lot more lively and tends to move between 0.2-0.58v. Neither of the O2 sensors ever read above 0.58v, even at WOT. I've also verified that the passenger side of the motor is leaner than the driver's side via a wideband.

At this point I've done the following:
- Checked both O2 sensors signal, ground, and heater wiring for continuity
- Replaced the O2 sensors with new NGK units
- Fixed an exhaust leak between the header and midpipe
- Smoked the motor and fixed a small leak at the TPS
- Checked all vacuum lines for leaks and replaced PCV unit

I am at a loss how to proceed getting the O2s to switch properly. The motor is a 4.6l with a Vortech supercharger in a draw-through MAF configuration and has a BBK 78mm TB. The EGR system has been deleted with a block off plate at the TB and a plug at the exhaust manifold.
decipha
Posts: 4957
Joined: 2021 Feb 15, 12:23
Location: Metairie, LA
Vehicle Information: Work Truck
'19 F-150 3.3L

Re: 04 Mustang GT O2 Issues

Unread post by decipha »

I just posted an o2 hego test tune for you. Load it in and see if the o2s act any differently.
viewtopic.php?f=27&t=80&p=424

Otherwise I would suspect bad fuel injectors. Which injectors do you have and where did you get them from? price?
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