Finally was able to get in the car long enough to record a log while driving. Hopefully I'm attaching it correctly? This is with a new oxygen sensor (Bosch 13077). I'm concerned that while holding at steady speed (approximately 40mph), the O2 reading is flat. Might be totally normal? I watched the O2 cross counts, that seemed ok, but again stayed flat for coasting sections. Any guidance much appreciated.
1978 Corvette with TBI System from 94 C1500. Installed in 2017, Fun Project!
Your "Closed Loop Idle" is checked. When I use "compare" to other bins, it is not checked. Your House Run xdl, closed loop flashes for a fraction of a second and purdy much stays open loop the entire log. I'm a little concerned that the log appears glitchy with alot of data swings???
Thanks for spotting the Closed Loop Idle flag. I will check that out and experiment.
You are right on the noise in the signal. I've seen that before on previous tunes and logs. My thoughts were that it must be something in the cable or auto prom as I could feel nothing causing disruption in the operation of the car. Is that a logical assumption?
1978 Corvette with TBI System from 94 C1500. Installed in 2017, Fun Project!
Trying out a new computer for tuning, an older HP laptop that is useless for modern work. Runs TunerPro just fine, and I'm a little less worried about it crashing versus the cool RCA tablet/computer thing I've used for years.
Made a new datalog with this computer and thought I'd post it for anyone with guidance. Still the same "noise" and glitches in the datastream, and the car will briefly enter Closed Loop then snap right out. By watching the bitmasks, I could see that the ignition was even seen as going switching briefly off.
These issues were not present when I initially tuned the car, but something is causing issues, at least with the datastream. The car runs great, no hesitating or stumbling.
Any recommendations on where to start on the "noise" reduction? I searched through the site and could not find info, so any expert advice would be greatly appreciated.
Thanks!
Matt
1978 Corvette with TBI System from 94 C1500. Installed in 2017, Fun Project!
I solved my glitchy data issue by adding a pause in the mode 1 commands sent by the adx file. See attached screenshots. Edit your adx file by clicking acquisition, edit definition, then commands . You are not entering closed loop because you have no real O2 activity. Faulty O2 sensor or improperly wired ?
Hope this helps,
Brian
Thanks Brian! I will definitely check if the steps you list help with the glitches. Something is definitely going on - I remembered I had a file of my test drive when I first installed the system, so loaded that up to compare. Sure enough, the data is nice and clean. And the oxygen sensor is performing exactly as it should, with the car going into closed loop.
When I first spotted the failure to go into closed loop, I watched and thought it could be the oxygen sensor. Brand new Bosch unit and it is performing the exact same as the original one (that worked until whenever I got into investigating the issues). Still have a few days to ship back to Amazon for a replacement.
Attached is the log of the test run when everything was running like it should. If I still get glitches after making changes that you listed, I'm going to start looking for RF noise in the engine bay.
1978 Corvette with TBI System from 94 C1500. Installed in 2017, Fun Project!
Added the pause command (thank you for the screenshots, those REALLY helped!) and the noise was greatly reduced. Log much cleaner. On first drive, was running poorly - bogging down and stumbling upon acceleration. Turned off, started back up a few minutes later and it ran like normal. Fortunately I had the laptop on board, was able to log both sessions. I'm leaning towards an ignition issue. Have a spare coil to try out.
1978 Corvette with TBI System from 94 C1500. Installed in 2017, Fun Project!
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