RTACS Strangeness

[DrX]

Used RTACS briefly a few months back and it seemed to work fine. In fact I ran off that tune since then with pretty stable AFRs(OL/SD).

Tried a couple of longer sessions during the last month during highway trips and ran into some issues. Just cruising, after a while my AFR started to fluctuate going leaner and leaner. Looked at my VE table and there were some very deep holes in it. Logged input from the wideband looked OK and matched the gauge. No lost connections. It's like the RR was started compensating in the wrong direction, making the problem worse and worse. It has happened after 30 min of RTACS, 90 min, and most recently it started acting up immediately. I had to go back to BEN/copy/paste and multiply tuning to get things sorted out.

Am I doing something wrong or is there something strange going on here?
I was using the most up to date software builds(until today's release).

TIA

[Blacky]

Just an idea...
Maybe cat overtemp protection kicking in? The PCM would try to command a richer mixture, RTACS would comensate by leaning out the VE table.

Regards
Paul

[Doc]

I am confused. You used the RR a few months back. Now the tune is lean? Do you mean you have been using the RR the whole time and now all of a sudden it is lean? Or, do you mean you used it to AutoVE w/RTACS back then and now, off the RTACS months later it is lean? If it is the latter then I would suspect that this is merely a condition of needing to update the OLSD tune (going from spring to summer is not a stretch.) Or, are you saying you have been using the RTACS the whole time and now it is going lean for some unknown reason?

[DrX]

No cats and B0701 is set to "Disable". Last time I started with a fresh tune on a cold start but after a couple of minutes putting down the road, running RTACS, the engine stalled because it went so lean.

[Doc]

Check the cal/integrity of the WB.

[DrX]

I am confused. You used the RR a few months back. Now the tune is lean? Do you mean you have been using the RR the whole time and now all of a sudden it is lean? Or, do you mean you used it to AutoVE w/RTACS back then and now, off the RTACS months later it is lean? If it is the latter then I would suspect that this is merely a condition of needing to update the OLSD tune (going from spring to summer is not a stretch.) Or, are you saying you have been using the RTACS the whole time and now it is going lean for some unknown reason?

The RR has been installed the whole time but I haven't done much tuning. The tune is stable as long I leave it alone. The problem only occurs during a RTACS tuning session. i.e. the automatic VE table updates seem to be working fine until at some point everything starts to go whacky. I have to disable RTACS, pull over, and manually repair the VE table to get back on the road. First time it happened I thouight my fuel pump was going out because of how the engine was behaving. But it looks like my fuel pressure is stable. The AFR just starts swinging deeper and deeper to the lean side due to the auto corrections being made by RTACS.

[DrX]

Check the cal/integrity of the WB.

According to the logged AFR values, RTACS should be adding fuel but it appears to start doing the opposite.

[Doc]

What filters do you have enabled?

[DrX]

No cal procedure for the WBC. What about a lag issue with the sensor/WBC or the update process? But why wouldn't it be there all the time? Smoothing on the wideband is set to 0. Did the same thing when I had it at 10/100.

I have a spare sensor that I might try when I get a chance to switch the connector on it.

[DrX]

What filters do you have enabled?

You keep getting ahead of me!

Filters are to exclude frames with: changes in ETCTP>5%/frame , MAP changes>8kPa/frame and MAP>105kPa.