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· Registered
Taco DC LB TRD 05
41 Posts
Discussion Starter · #1 ·
Hi guys,

I need someone to explain me when tuning my MAF in oppened loop (WOT) why i can't install the LM-1 sensor in place of one of the O2 sensors in bank 1 (before the first cat). If i use one, i will probably have a check engine but does the engine will use the remaining one to ajust injection. If i really have to install to LM-1 sensor on the second bank after the first catalyser, which correction i should apply to the reading i will have.

In the same order, when you install an aftermarket headers and an Y pipe, i can't understand that we have to install an o2 sim for the first bank (injection loop) and just re-install the second bank (catalyst status) o2 sensors on the bungs installed on the Y-pipe ? For me it seems more logical to have bungs on the headers for the first bank and just keep the injection control loop trully operative and install a o2 sims on the second bank.

There's probaly something i'm not understanding. Thanks

· Super White Taco
2005 Tacoma
824 Posts
The 1st set of O2 sensors (before the cats on stock headers) are required to be installed since they monitor and adjust the fuel trims in closed loop. Even aftermarket headers (example DT Longtubes) have bungholes for the front O2 sensors. The second set of sensors (behind the cats on the y-pipe) only monitor the health of the cats and don't affect engine performance, so you can use one of those to install your wideband sensor. Yes, you'll get a CEL light, but your closed loop fuel trims will be accurate and you really don't need to make any adjustments to your AFR readings because they'll be pretty close in open loop mode. If you install aftermarket headers, which consequently removes the 1st set of cats, or want to replace the second set of sensors with a permanent wideband sensor, you can install an O2 simulator which will override the error code.

· Theatre Nerd Person...yea
1,974 Posts
^^^ +1

Or if you want I do believe URD sells a module that takes the input from a Wideband Sensor and emits both a Narrowband and Wideband Signal. The Narrowband signal goes to your ECU and the Wideband signal can go to a gauge or a computer for tuning it's a very neat little module.
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