02 LC-1 Sensor signal erratic driving me crazy! 380SE

[harlz]

I've been trying to get a useable 02 signal to tune my engine for days, and I can't figure out what's going on! I have an LC-1 and I get ~5v at the brown terminal (now it's wired right). I ran a log of what I saw in the car and also pulled the ECU out and checked with the stim. Its like it is only giving output erratically. I have both tables to look at if anyone can see what's up. It looks like MS is built ok since the signal shows up ok in both MT and Tuner Studio MS.

I haven't used the "Calibrate AFT Tables' yet, but I have selected the right settings for teh LC-1 in EGO control (settings INI for MT).

I'm just a little worried about blowing up my engine... I've got a temporary air filter that's pretty restrictive which buffers any sudden or large throttle action.

02 stim test.msl

02 sensor on test drive.msl

Too add to my frustration, I have a new laptop with no serial port (using prolific USB) and I have connection issues. Tuner Studio is stable, but MegaTune disconnects and sometimes crashes my pc.
I haven't got resistor plugs, however the car has 10K ohm Bosch resistor leads - not sure if this is an issue. Everything is grounded to the same point at the negative battery chassis mount (MS and LC-1) and the LC-1 is getting +12v from the Merc fuel pump relay.

MSII/V3 Board Latest code

Thank you all!

[Matt Cramer]

You must set up your MS2 for the LC-1 using Tools -> Calibrate AFR Table before you get results you can use. This is as important as wiring the LC-1 to the MS2; it won't work without doing both.

[harlz]

Excellent! Thanks for that. I have my Girlfriend's ancient laptop with a real COM port now, so I should be able to have a reliable connection to MS. We shall see!

[harlz]

I've updated the AFR tables, but it hasn't helped the situation much. The signal spikes are still huge and don't appear to relate very well to anything. Is there a way to get AFR data from the data out 3 1/2" plug on the LC-1?

[harlz]

I've narrowed the problem back to the sensor output, it's very erratic at the analog outputs. It starts up smoothly, then jumps around and will not give a useable output. Any tips?

[Matt Cramer]

I'd first check for bad grounds. Also make sure the LC1's cable is not near noise sources like spark plug wires or the alternator.

[harlz]

I think I solved the problem! It's a pretty obvious solution, but I didn't know that if the sensor is disconnected from the controller for any lenght of time the calibration is reset. My sensor wasn't securely plugged in at the start when I installed it in the car I think, as I did the calibration on a bench beforehand. I re-did the calibration and at least from the multimeter, looked very stable. I'm thinking that if the sensor took the startup exhaust as nominal oxygen content, that would explain a few things

Let's hope this fixed it - this has been a nightmare trying to figure out what I did wrong and getting nowhere with the tuning! -Thanks for the help and suggestions, I'll let you know if it looks good in MegaTune.