How to: Datalog inputs directly into the ecu
Wideband / Boost/Fuel/Oil Pressure

by Michael Decipha Ponthieux
Posted: 2016-11-17
Last Updated: 2023-01-04

Hardware Setup - datalogging a Wideband through the EGR 0-5v EVP (EGR Valve Position) or DPFE Input

Most all EEC's have a 0-5v analog input used by the egr valve position or DPFE. This input can be reused to datalog a 0-5v input such as a wideband. Note: The EGR will still function so the EVP sensor or the DPFE sensor must be unplugged! The EGR will still be commanded but the PCM will just not have any feedback to know if its flowing correctly. See the ECU Pinout List for which pin is the EGR Valve Position (EEC-IV) or DPFE (EEC-V). Typically on EEC-IV this is usually ECU Pin #27. On EEC-V this is usually ECU Pin# 65. Be sure to verify.
NOTE: It IS NOT RECOMMENDED to permanentely remove or disable the EGR unless absolutely neccessary. EGR should be plugged back in and re-enabled in the tune after WOT fuel has been dialed in and the wideband is no longer wired in to the egr input.

If you do not have the ability to add in an additional bung for the wideband you have the option to disable hego2 (driver side) and install the wideband in that bung while tuning. See the Tuning Tips Write Up for more details.
NOTE: A wideband is too slow and not accurate enough to simulate a narrowband. NEVER use a wideband to simulate a narrowband. The wideband narrow band output should NEVER be hooked to the factory narrow band input under any circumstances for any reason.

First you must unplug the egr valve position sensor from the EGR valve and/or the EGR flow sensor.
Installation is as simple as hooking up the widebands analog output 0-5 volt wire to your ecus egr valve position wire TAPPING the wire at the ECU Connector.
NEVER connect the wideband output to the egr connector in the engine bay since resistance in the wiring will cause the wideband to read wrong.
The full ecu pin out is available by CLICKING HERE.
You should always source a fused 12v ignition feed directly from the fuse box. Be sure you tap into the FUSED out and not the UNFUSED in.

Verify your wideband transfer function for your wideband with the transfer below. Always verify with the manual included with the wideband and not the online info as transfers vary by model.

Wideband Transfer Functions

WBo2 - LC-1 / LC-2 / MTX-L / DLG-1
(0.2046 * (X/12800) ) + 0.5
(7.35 + ( X / 4267 )) / 14.64
WBo2 - AEM
(2.375 * (X/12800) + 7.3125) / 14.7
WBo2 - AutoMeter
0.119 * (X/12800) + 0.68
WBo2 - PLX
( 0.136 * ( X / 12800) ) + 0.68
WBo2 - B
(7.35 + ( X / 4267 )) / 14.64
WBo2 - C
X * 0.000010625 + 0.683
WBo2 - D - NGK AFX / **AFR500
(9 + ( (X/12800) * 1.4)) / 14.7
WBo2 - ZT3 Ver.2
0.158 * (X/12800) + 0.640
WBo2 - ZT-3
0.136 * (X/12800) 0.653
(2 * (X / 12800) + 9.6 ) / 14.7

**AFR500 when set for default gas scale.

Note: By using LAMBDA the wideband calibration is impervious to alternate fuels.

If your transfer is not listed, post your transfer function on the
Forum to be added in.

Software Setup

TunerPro RT
If your are using TunerPro RT you are finished since no setup is required! If your wideband is listed above you simply right-click on WBo2 on your tunerpro dashboard and select your wideband from the drop down menu (WBo2-AEM, WBo2-LC1, etc..).
If you forget to select the wideband on the tunerpro dash keep in mind Tunerpro actively logs all transfer functions above so you can select your correct wideband transfer even after making a datalog and it will always be correct.

In all cases, after you have selected your wideband you must VERIFY your wideband is reading accurately. To verify your wideband transfer you must compare your widebands digital gauge with the reading on the tunerpro dashboard. They should match closely under all conditions. To make sure the wideband reports stoich correctly hold the vehicle at a steady cruise speed on the highway; with the vehicle in closed loop o2 sensor control, the wideband will jump above and below 1.00 lambda. If it does not, note the average lambda reported on the wideband. This is your wideband error. While dialing in your fuel, you must verify the wideband matches the dashboard value while in enrichment when the ecu goes in to open loop fueling such as WOT conditions. If the wideband error compared to the digital gauge reading has the same error at cruise that it does at WOT, then your wideband transfer can be shifted to report more accurate data. When doing so, if you are getting a
REMOTE TUNE, you MUST let your tuner know otherwise they will have inaccurate information!!!

Transfer Technical Support and Equations - for INFORMATION ONLY (and to shift the transfer)

in tunerpro edit the ADX >> Values >> WBo2
then click on conversion

at the top you'll see the equation click on set

X is the EVP raw input voltage which is the widebands actual output voltage, 0 - 65535 a/d counts correlating to 0v to 5v respectively.

A wideband outputs a linear voltage based on air fuel ratio, thus one can logically infer the equation for the wideband transfer is a simple interpolation equation. The following is the basics to compute the equation.

For Reference:
32,000 ad counts / 12800 (ad to volt conversion) == 2.5 volts
so for an equation that is 7.35 + ( X / 4267); 3.1v [stoich which correlates to ~16.6 AFR for a 2.5v stoich] the correct equation is 0.16222 * ( X / 12800 ) + 0.5

Shifting the Wbo2 Transfer

If you have verified that your wideband is reading wrong "LINEARLY" on the dashboard as compared to your wideband gauge reading, you can shift the transfer by doing the following:
in tunerpro edit the ADX >> Values >> WBo2
then click on conversion

at the top you'll see the equation click on set
at the very tail end of the equation add
* x.xx

x.xx being the percentage your wideband is reading off (from 0.90 to 1.10)
If your wideband is reporting more than 10% off then you have the wrong transfer selected.

In all cases, if you are getting a REMOTE TUNE be sure to notify the tuner otherwise all of your corrections will be wrong.

Wideband non-linear ?

Then you will have to "add" a new transfer to be able to 'define' the range in which your actually using it and can have useable data and corrections.

On the dash, right click the wideband paramter and select IEGR. Now Watch the IEGR voltage closely while in closed loop AND the o2s are switching AT a stable highway speed in the higher rpm range. In your head AVERAGE the TYPICAL imaf voltage. This will be the voltage for STOICH and will be accurate so long as the o2s are switching and controlling fuel correctly. For this example the average logged imaf while at stoich cruising average about 2.8 volts.

Now find the enriched voltage while in open loop at wot having a known lambda (like say using the actual controllers gauge). If thats not feasible then you will have to force open loop at cruise and command your enrichment lambda. Again, average the typical imaf voltage in your head while the wideband is reporting a known lambda. For this example the average logged imaf while at .78 lambda reported on the gauge was about 1.5 volts.

With this data you can now interpolate the lambda at 5v == 1.372 and interpolate the lambda at 0v == 0.526

Now simply compute the new equation as outlined above.
For this example:
1.372 - 0.526 == 0.846/5 == 0.1692
0.1692 * (X/12800) + 0.526

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