EGO reading steady 7.4 in MegaTune with LC1

[amrcnv8]

I am having trouble getting the EGO reading to show up in MegaTune; all I get is a constant 7.4 AFR on the gauge and the real time screen.

- I have confirmed ~4.897V on the wire going to the EGO input on the harness (free air)
- LC1 is working/reading correctly as indicated on the DB gauge (no error lights and showing 21.9 in free air)
- Solder connections on the board look good (R10, R11, C10, Daughterboard and RS232)
- I verified continuity to each side of R10 and R11 from pin 23 on the MS2 V3 board (I didn't get much from C10, but maybe that is normal for a cap?)
- I have tried downloading the AFR for Innovate LC1 in the calibrate AFR menu several times, even switching between Innovate 0-5V and back (didn't save msq each time, maybe that has an effect if the msq is corrupted?) All 1024 bits of data are transmitted followed by a faint "beep" from the MS2 after download.
- I have tried two different LC1 ground locations, including the current location of the engine block to firewall ground strap, which is common with the 5 wires to the MS2.

Please help! Any ideas?

[Matt Cramer]

I'd like to check some other settings; could you please post a copy of the MSQ?

[amrcnv8]

I'd like to check some other settings; could you please post a copy of the MSQ?

Thanks for the help and the quick reply. Please find the msq file attached.

[Matt Cramer]

The MSQ doesn't have any obvious issues. Can it display the full EGO range on a Stimulator?

[amrcnv8]

The MSQ doesn't have any obvious issues. Can it display the full EGO range on a Stimulator?

I remember it using quite a bit of the potentiometers' range early on, then it seemed like it was only using a small portion of one end of the potentiometer towards the end of the build. It did swing through the full range of AFR, just taking a very small movement of the pot.

I'll hook up the stim tonight and see if I can grab the voltage range when it is showing the AFR on the gauge.

[amrcnv8]

The MSQ doesn't have any obvious issues. Can it display the full EGO range on a Stimulator?

I'll hook up the stim tonight and see if I can grab the voltage range when it is showing the AFR on the gauge.

Works great with the stim with msq attached earlier, full range on the pot and getting ~4.9V at R11 when pot is maxed. I guess I'll try checking the O2 wire through the connector to make sure that it is getting to the computer. Not sure what else to try..

[amrcnv8]

Seems to be working now. I think two things lead me awry here:

- LC1 needed to recalibrate the heater coil, despite having been working before. No big deal, I just needed to recognize the blinking light error code and look up the code in the LC1 manual to figure that out.
- It appears that MegaTune needs the engine to be running in order to sample the O2 signal. I'm not sure if this is because other signals prevent the program from sampling or if it is something else. With the key on, engine off and LC1 warmed up and sampling, the O2 will not show up on MegaTune. With the engine running, it shows up.

While I did try running the engine before to see if that made a difference, I hadn't run it since I'd gotten the LC1 working properly.

Thanks for your help Matt, you've been a great resource. Just wanted to document the resolution to hopefully help someone else if they encounter the same situation in the future.

[Matt Cramer]

- It appears that MegaTune needs the engine to be running in order to sample the O2 signal. I'm not sure if this is because other signals prevent the program from sampling or if it is something else. With the key on, engine off and LC1 warmed up and sampling, the O2 will not show up on MegaTune. With the engine running, it shows up.

That's a very common source of confusion. MS2 is set up so that its O2 sampling rate is keyed to the engine RPM. The way it works, it updates the O2 number every so many tach pulses. So if it's not getting a tach pulse, its sampling shuts down and the O2 value will appear to be stuck. I've seen quite a few people think the circuit was broken, when it turned out it was working perfectly well but waiting for a tach pulse to get a sample.