Logging wideband through EGT input

Got a wideband AEM UEGO gauge ready to be installed. I just need to figure out the wiring for logging and it would be nice to just have to connect to the OBD2 for logging.

 

Ive read up on people using the TGV Sensor Input but for now Im trying not to mess with them that much.

 

However, when I went catless on my uppipe I removed the EGT Sensor and have and empty input. From what I can see the EGT still outputs from 0-5v same as the output of the gauge. Not sure if theres a refresh rate or delay issue with the EGT.

Use the rear o2 loom, heaps of info online.

Or go mafless and use that loom but seperate from the iat sensor.

 

Or use a serial to USB converter and use it as an external sensor in Romraider or via custom pid in Btssm.

Iirc a phidgets I/o box can do similar with 0-5v sensor outputs.

 

I’m not sure about the egt option, I’ll have to look it up

Edited October 13, 2019 by bigBADbenny

Use the rear o2 loom, heaps of info online.

Or go mafless and use that loom but seperate from the iat sensor.

 

Or use a serial to USB converter and use it as an external sensor in Romraider or via custom pid in Btssm.

Iirc a phidgets I/o box can do similar with 0-5v sensor outputs.

 

I’m not sure about the egt option, I’ll have to look it up

 

With the mafless option, im guessing speed density would be used instead? Ive been in the process of setting that up but the reason for the wideband is to try and dial in my CL MAF scaling.

Edited October 13, 2019 by dwmccauley01

Which AEM wbo2 is it?

The type of output options may influence your choice of logging it.

Also the type of logger, eg tactrix, Btssm etc.

 

I forgot to mention another option is the 2.5mm socket on a tactrix which accepts 0-5v input when used in standalone logging mode.

I don't have a tractix at the moment. I'm not exactly sure the type because I got it off a friend..

 

Pretty sure its a older one but the part number is 4110-73392. It uses the Bosch LSU4.9

 

Sent from my VS501 using Tapatalk

Which AEM wbo2 is it?

The type of output options may influence your choice of logging it.

Also the type of logger, eg tactrix, Btssm etc.

 

I forgot to mention another option is the 2.5mm socket on a tactrix which accepts 0-5v input when used in standalone logging mode.

 

My bad, if you meant tractrix vrs. Cobb Ap I am using an openport cable that isnt tractrix but it works with the software.

Alright so after some research I have a plan.

 

Me writing this is also for me to make sure everything is logical.

 

I wasnt clear before, but the way I flash and log is through my laptop connected via a cable to the OBD2 port. I looked into the analog output of the gauge, but that would require a R-232 to USB converter somewhere and I would need to have two USBs sticking out of my laptop while logging which is not ideal.

 

As far as attaching the input to the EGT Input and reprogramming parameters in romraider, the only concern for me is delay in the sensor input itself. Given the EGT is connected to the ECU at pin 24 of the B136 section, the same as all other sensors, I think it will be fine.

 

I'm aware of people successfully connection the TGV and rear O2 input to the wideband. The EGT have the same two wire input (assuming power and signal?) as the TGV and I read of an individual using the TGV input as an exhaust temp sensor input : https://forums.nasioc.com/forums/showthread.php?t=2744832 Post #7.

 

So, it seems as long as connections and grounds are set up properly, most any 0-5v sesnor input should work with the gauge's serial output.

 

Now the more involved part: the installation.

I could potentially just splice the wires directly from the TGV input and do away with the input housing itself, or for an adittional $12-15 I could order an EGT pigtail. From what I read the heat from the exhaust piping itself instead of the gasses cause damage to the sensor so I'll look at getting an M18 nut welded to the downpipe and add a thin washer to act as a heat sheild. From there its just wiring everything up. Most likely with draw power from the nearby cigarette lighter and ground elsewhere.

 

The pictures compare the EGT to TGV signals and shows the 0-5v scaling of the EGT sensor.

You should PM utc_pyro but I don't think you can use the egt as it actually uses resistance rather than voltage. I'll edit my post if I'm wrong but I think it's been asked before.

 

See here:

 

http://www.romraider.com/forum/viewtopic.php?f=15&t=3479

Edited October 15, 2019 by rhino6303

You should PM utc_pyro but I don't think you can use the egt as it actually uses resistance rather than voltage. I'll edit my post if I'm wrong but I think it's been asked before.

 

See here:

 

http://www.romraider.com/forum/viewtopic.php?f=15&t=3479

 

Ah that is unfortunate. I searched around but couldn't find anything relating to it.

 

I do wonder if a voltage controlled resistor would work because the EGT sensor is basically a thermal sensitive resistor that increase resistance basd on temperature. That may just be another variable to make things more complicated and possibly delay the input, but if I can find a voltage controlled resistor which will make the EGT resistance equivalent to the wideband output it may still work.

 

Another option would be a rear O2 delete. Wiring would be fairly easy but I have read that the rear O2 has an input only from 0-2.5v. I'll have to do some more searching.

Nevermind! I just realized in my tune the AF #3 was disabled awhile ago so the rear O2 is not doing alot at this point. Guess that is the best option because I will probably remove the 1st cat in the downpipe sooner or later making the rear O2 useless.

I got the bung welded into the downpipe about 6-8 inches after the turbo and before the cat.

 

Just to clear up some confusion, the rear O2 sensor, in the downpipe, can be disconnected and the 0-5v input from the wideband can be connected to the input of the rear O2 for logging?

 

I dont see scaling or a way to view the rear O2 signal in Romraide. Am I missing something or do I need to add a parameter to both the ecu and logging definitions?

Got everything done and its working surprisingly well, changed the logging parameter on romraider and it logs faster than the stock AFR sensor.

 

Only problem is the conversion from volts to AFR is off a bit. Does anybody have the conversion for the LSU4.9 V to AFR?

 

Sent from my VS501 using Tapatalk

Got everything done and its working surprisingly well, changed the logging parameter on romraider and it logs faster than the stock AFR sensor.

 

Only problem is the conversion from volts to AFR is off a bit. Does anybody have the conversion for the LSU4.9 V to AFR?

 

Sent from my VS501 using Tapatalk

 

Should be in this install guide.

https://www.jegs.com/InstallationInstructions/0/017/017-30-0310n.pdf

I think I am going to do exactly what you did OP.

I think I am going to do exactly what you did OP.

It was fairly straight forward. Welded a bung on the downpipe, spliced into the rear O2 sensor output (blue wire) and wired everything through the driver side wheel well. Put the gauge inside the center cubby thing. Power came from an add a fuse since the wires had to come through that area anyway. Changed logging parameters to match the volts to AFR converion, disabled related sensor CELs and AFR #3 learning.

 

Hardest part was getting the wires routed under the steering wheel.

 

Sent from my VS501 using Tapatalk

Could you provide more details on the volts to AFR conversion part? I also use btssm and would like to log/view the AFR just like you.

Why did you have to disable the AFR #3 learning trim?

Could you provide more details on the volts to AFR conversion part? I also use btssm and would like to log/view the AFR just like you.

Why did you have to disable the AFR #3 learning trim?

 

 

From my understanding, our generation uses the rear O2 for highway driving and the upper ranges of the closed-loop fueling. You may be able to directly replace the rear o2 sensor with the wideband depending on your set up. For me, the sensor reads a lot richer than the stock rear O2 because it's before any cats, about 8 inches from the turbo. The readings were so rich that it threw a CEL. From what I've read, straight up removing the rear O2 with no change to tune causes the AFR#3 to read really rich which can cause too lean of conditions in Open Loop. It doesn't make much sense to me to have the car try to maintain the 14.7 in the open-loop airflow range because the whole idea of open-loop is to stray away from the 14.7 AFR.

 

[Edit: AFR#3 is calculated by the reading from the rear O2 in closed loop to monitor cat efficiency. Directly connecting the wideband before the cats will cause the AFR#3 to be too rich. I believe ECUFlash has the parameter that can be disabled or altered]

 

Im actually using romraider and my laptop at the moment but I will most likely set up btssm at some point.

 

From the btssm manual, it looks like you can just add a custom parameter with the same address as the rear O2 voltage, just change the formula.

 

https://www.btssm.com/manual.html#customfields

 

Not sure which gauge and sensor youre using but any voltage to AFR conversion is going to be a linear relationship. Im using a AEM UEGO 30-4110 with the Bosch LSU4.9. I got the equation from entering the data from the manual into excel and getting the line of best fit equation. I still have to make adjustments to dial it in but right now, Im at AFR = 1.9987(x/200) + 10.001.

 

Heres my code from romraider:

 

</parameter>

<parameter id="P15" name="Rear O2 Sensor" desc="P15" ecubyteindex="9" ecubit="1" target="1">

<address length="2">0x000018</address>

<conversions>

<conversion units="AFR" expr="(1.9987*(x/200)) + 10.001" format="0.00" />

<conversion units="V" expr="x/200" format="0.00" />

</conversions>

Edited October 28, 2019 by dwmccauley01

Got the whole wideband pretty much sorted out. Still need to find a way to calibrate the sensor with the voltage output, but the sensor and gauge is working very well. If anyone wants pictures or anything I would be happy to post them here.

 

I apologize for my confusing previous post, the AF #3 was not disabled, but I disabled AF#1D. After running the sensor for a week or so, I kept getting some weird fuel corrections in the highway airflow range. Turns out, as I said before, the rear o2's reading was translated to AF #3 which is then used to adjust all the upper range AF corrections (short and long term). Leaving AF #3 learning enabled to see what would happen caused some interesting learning views. Drove home from work and the AF#1C was at +4%, the next morning I drove back and it was maxed out at +15% (Note that this was partially my fault as I unintentionally scaled my MAF twice, removing 20% from one cell). To disable AF #3, I had to do some searching on the interwebs and I came to a parameter found by td-d:

 

http://www.romraider.com/forum/viewtopic.php?f=40&t=8131&sid=a53e556bf5aa5955f883e9a737550e3f

 

My code I put in the definition for A2WC521N:

<table name="AF 3 Correction Limits" address="2df2c" type="2D" level="1" scaling="A/FLearning#1Limits(%)">

<table name="X" type="Static X Axis" elements="2">

<data>High</data>

<data>Low</data>

</table>

</table>

 

Note: the address of the limits will be different depending on the image you are running

 

The fuel trims all are staying around +/- 3% after I disabled the AF #3 correction.

 

Now off to get that open loop scaled

Any update OP? How is everything running now? I am about ready to do this (got a wideband, and an o2 bung welded.

Any update OP? How is everything running now? I am about ready to do this (got a wideband, and an o2 bung welded.

I got it hooked up and set up the parameters for logging and it works well. The main issue I've run into is getting the voltage to AFR equation to accurately produce the current ratio. It shouldn't be too hard to fix since the AFR and voltage relationship is linear, I just haven't taken the time out to finish it. I think mounting a camera to view the AFR on the gauge and RPM would be one of the easier solutions unless you have an analog output on your gauge.

 

I did get a trouble code for the downstream sensor being too rich for obvious reasons. I also havent gotten the parameters set up for btssm but I haven't looked into it too much.

 

 

Sent from my SM-G970U using Tapatalk