Issues with oxygen sensors with tune

VersaTuner for Mazda RX-8
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el conquistador
Posts: 9
Joined: February 12th, 2015, 3:41 pm

Issues with oxygen sensors with tune

Post by el conquistador »

I guess I'll be the first customer to make a thread in the RX-8 forum.

I got my VersaTune set up yesterday and wasted no time in putting it on my 2009 RX-8 R3. First I tried the included tune for better fuel efficiency and tweaked the idle speed and second fan temperature slightly and blocked P2270 since I don't have a cat. Then I tried starting with a stock tune and tweaking it. I noticed while driving around taking logs to calibrate my MAF that the fuel trims stayed at zero. I added fuel status onto the log and it stayed in mode 8, open loop due to a malfunction. It was at that point that I noticed the CEL had come back on, and I pulled the following codes.

P0032
P0038
P0137

I reset them but after two cycles, they came back. I never got these codes before with the factory firmware, but just to make sure it wasn't a blown fuse or damaged circuit, I reverted back to the factory tune tonight. I ran it through two cycles. My Ultragauge showed that the ECU went into closed loop and when I pulled the codes and pending codes, it had only P2270.

So I'm wondering if I did it wrong or if the software doesn't like my particular ECU.
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Steve @ VersaTune
Lead tuner
Posts: 1157
Joined: March 29th, 2010, 12:58 pm

Re: Issues with oxygen sensors with tune

Post by Steve @ VersaTune »

PM sent with instructions to send me your ROM file for analysis.


Steve
el conquistador
Posts: 9
Joined: February 12th, 2015, 3:41 pm

Re: Issues with oxygen sensors with tune

Post by el conquistador »

I thought I had already posted a reply in here. I got a new version of the software last Monday that is more compatible with my car. I've been playing with it and haven't noticed any issues so far. I've been really enjoying playing with it.
WankeYankey
Posts: 5
Joined: August 16th, 2021, 12:17 pm

Re: Issues with oxygen sensors with tune

Post by WankeYankey »

Hello I also seemed to notice I could not get my actual AFR to show up during any logs, only target AFRs. Could this mean they are not working or not properly connected? I've had issues with my harness before but I also wouldn't be surprised if it was an issue with my setup and installation process as it took multiple attempts to get right if I even accomplished that. I am using the series I software on a 2004 model.
brightson
Posts: 1
Joined: March 6th, 2022, 5:56 am

Re: Issues with oxygen sensors with tune

Post by brightson »

Interesting...I didn't realize that it's possible to end up with a version of Versatune for RX-8 that's incompatible with RX-8 (assuming it's for your series # in the first place). Is the issue just an update thing? I see that the OP was from a number of years ago, but Versatune is behaving differently now than it was when I first installed it and although it's up to date I'm now wondering if reinstalling a "newer version" would make any difference/correct the problem...

Initially one of the features I utilized was DTC masking to accommodate my catless setup. It seemed to work just fine for the first year or more with the occasional reflash of a modified tune. At least, the CEL never came on anyway. (I mention this because I recall reading that the software only prevents the CEL from illuminating and that the code would still come up if you checked.) Still very unclear as to the truth behind that statement though. Either way, the CEL does come on now with a P2270 code which is downstream O2 sensor stuck lean. When this first started happening I replaced the sensor but the CEL still came on. So I replaced the other sensor (upstream, air/fuel mixture sensor so technically not an O2 sensor) to no avail. Then I replaced the downstream sensor again but I still get the light and the P2270 code. (These are all OEM Denso units so I can safely rule out garbage aftermarket parts as the culprit.)

Coils are IGN-1A
Plugs are stock NGK (verified authentic)
Wires are from SAKEBOMB
Fuel pump is only 2 years old, from the factory recall

I guess I'll start hunting down a connection issue or something of that nature.

The other codes that come up at the same time are:
P0301 (front rotor misfire)
P0410 (secondary air)
P0442 (small EVAP system leak detected)

The secondary air injection system code is supposed to be masked as well because I deleted my pump.

I have searched high and low for a vacuum leak and have never found one but that code doesn't concern me too much at this point.

What does concern me is that I want to get further into tuning my car but can't even get thru the crucial stage of MAF calibration, upon which everything else heavily depends.

My question is: When you mask all the codes associated with a cat delete does it really stop the computer from checking for the cat, or does it just prevent the CEL from coming on? If it's the latter then I'll never be able to tune my car if it's running catless, which is essential for longevity of the Renesis.

BTW, this situation does not cause the car to go into limp mode. Power and performance do not seem to be compromised. Fuel consumption is as crummy as any other '8 and I drive the piss out of mine.

Hopefully you guys can clear up some of the cloudy information that's out there. I'm sure I'm not the only one who has been wondering this for some time now.

Thank you!
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Ugnius @ VersaTune
Lead developer
Posts: 580
Joined: March 19th, 2010, 11:57 am

Re: Issues with oxygen sensors with tune

Post by Ugnius @ VersaTune »

VersaTuner is compatible with all Mazda RX-8 vehicles. If you stumble upon an ECU calibration that we have not seen yet, we add support for it in 1 business day.
We may fix bugs or add new features to the RX-8 platform as time goes by. I don't think your issue is related to VersaTuner, but feel free to install the latest version and flash the tune to the car again.
Disabling DTCs only prevents the code from being shown, if there are related internal ECU checks, they will still run. But removing the cat is usually not a problem and will not cause the car to get into limp mode or smth.
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