stumbling issue

[gotjaydee]

ive been having issues with my car stumbling at times, I was able to catch it on a datalog, the problem happens at the 2 minute mark through the 2:20 mark. the car is a 95 civic with a b20 swap, running the hondata b20 base map. can anyone tell me what might be causing this issue

[Hondata]

It is the o2 sensor or something to do with the o2 sensor, like an air leak in the exhaust.
At the 2 minute mark you'll see the short term fuel trim goes to -29%. Without a wideband it is hard to say but I would think that is running lean at that point which causes the hesitation.

[gotjaydee]

Thank you for the info, I was starting to plan towards that after looking at it a bit longer, could I get ride of the factory 02 sensor and just run a wideband?

[Hondata]

Yes, you can replace the factory o2 sensor with a wideband and run closed loop from the wideband/

[Danielr96]

I had this same issue on my car today. Everything had been running good until I updated my smanager to the newest beta version and made changes to my launch control and uploaded the calibration. As I was driving, my short term fuel trim suddenly went down to like -20 and the car kept stumbling and not running correctly.

After looking over the calibration thoroughly, I noticed that my rev limit per gear had changed to 2500 across every cell. I had definitely not done this change myself. I think the calibration got corrupted or something of that sort had happened. What I did was opened a new calibration and copied over my ignition and fuel tables, etc. Gonna try it tomorrow and see if it fixes it.

You should try doing the same with a fresh calibration and see if it helps you. Good luck!

[gotjaydee]

I've actually been having this problem for awhile, but recently it has gotten worse, when I went to hook my computer to my ecu is when smanger updated, but I will definitely look into what your talking about, originally I thought it was my aftermarket tps but I'm starting to think it's the 02 sensor like the admin suggested, I turned off the closed loop to see if that fixes the issue/eliminates 02 sensor

[gotjaydee]

I ran on open loop for a week and didn't have an issue, then I changed it to closed loop and the issue came back