TunerStudio not reading O2 sensor

[jashencoles]

Hey everyone!

I am currently trying to set up a throttle body injection system on my 1973 Dodge Dart Sport. I am using the megasquirt II controller (V3) with the relay board. Right now, I still have the carburetor on the engine, but have the RPM, MAP, O2, and coolant sensors hooked up to the relay board. I connected the Megasquirt controller to my laptop (using Tunerstudio) to verify that everything was reading correctly before proceeding. The other sensors work fine, but Tunerstudio is not displaying the correct AFR.

The wideband controller is an Innovate LC-1. At first, I had the output 2 wire connected to both to the included gauge and the megasquirt unit. The gauge seemed to be reading correctly, but Tunerstudio displayed a constant 12.1 AFR. Next, I programmed the LC-1's output 1 signal to match the output 2 signal (both are now 0V = .5 lambda and 5V = 1.5 Lambda). Output 1 is connected to the relay board, and output 2 is connected to the AFR gauge. Now, Tunerstudio displays a constant 14.7 AFR.

I have verified that the project settings in Tunerstudio are set up for the LC-1 default option (0-5V = .5-1.5 lambda), and that the EGO settings are all set up for wideband. So, I am having trouble understanding why the AFR is not updating/displaying correctly. If it helps any, the digital gauge reads ~14.5 at idle and between 10.0 and 12.0 above 1500 RPM. And, the LC-1 Logworks software reads very close to the gauge when I connect to it using the serial output.

If anyone has any input on this, I would greatly appreciate it!

Thanks!
-Jashen

[jashencoles]

This morning, I was going through the settings in Tunerstudio, and saw the option to calibrate the AFR table (the only option I think I missed before). So, I tried setting it to the default LC-1 output, and updated the controller. Instead of reading 14.7, tunerstudio then read 7.8 when the engine was warmed up. I then tried calibrating the afr table with "custom" values (0-5V = 7.35-22.05 AFR). Still, tunerstudio reads a constant 7.8 AFR.

Today, the gauge is reading approximately 12.0AFR at idle. So, I am wondering if there may be a setting I am missing that is causing the megasquirt to reading the LC-1 as a narrowband O2 sensor? When it was close to stoichiometric, tunerstudio read 14.7. Now that it is running rich at idle, it reads 7.8 (which is the same as the gauge reads when the sensor is warming up). Just an idea...

Again, if anyone has any input, I'd really appreciate it.

Thanks,
Jashen

[Matt Cramer]

First, could you check the voltage on the LC-1's output and let me know if that is reading OK?

[jashencoles]

First, could you check the voltage on the LC-1's output and let me know if that is reading OK?

Thanks for the reply, Matt!

I checked the voltages of Output 1 and Output 2. Output 1 is reading 0V, and output 2 is reading 1.8V (very close to what the gauge reads. So, that explains why I am reading 7.4 all the time now. I'll try hooking it up to Output 2 later in the week when I get some time to work on the car, but it didn't read right when I had it hooked up there the last time. I did have both the wire going to the relay board and the wire for the digital gauge hooked up the the output 2 wire. Would that have been too much for it? The gauge still read/updated fine, but TunerStudio was reading a constant (incorrect) AFR.

I'll post an update when I have one. Thanks again for the help!

-Jashen

[Matt Cramer]

Ok, so the LC-1's OK. Does the AFR respond correctly if you test the MS on a Stimulator?

[jashencoles]

Ok, so the LC-1's OK. Does the AFR respond correctly if you test the MS on a Stimulator?

Matt,

I found that the wire I was using to go from the LC-1 output to the relay board had a kink in it. I replaced the wire. I still can't get a reading using the output 1 (after setting it to output the same as output 2), but it seems to be working fine hooked up to output 2 along with the gauge. Now tunerstudio and the gauge have identical readings.

Unfortunately, my exhaust flange gasket blew out (again), causing the LC-1 to read that the engine is running lean. I'll have to wait until I get a new gasket in before trying to start/tune the engine with the TBI setup.

Thanks again for the responses!

-Jashen