Wideband o2 recommendations?

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May 17, 2023 | 03:23 PM

jmgtp

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Wideband o2 recommendations?

Trying to get a bit more serious about tuning. Fighting some KR in the very top end, I noticed my PE % RPM table goes way negative in the same rpm where I see KR. Logically that didn’t make sense to me so on a complete guess, I added a little fuel by adjusting that table. Not only did the KR go down dramatically, the power in the top end was very noticeably improved. So I think the fueling in my tune aint right and you guys probably warned me about a mail order tune, but I’m a bit out of options. No one wants to touch an OBD I C4. So I’m trying to do this on my own, obviously without a dyno and presently not having real AFR data makes this a total crapshoot.

So, wideband… I do need to do more reading and a lot of the threads I find are 10-15 yrs old so I’m sure what is available has changed. Hardware aside, seems feeding the data through the AC pressure switch is the way to go but I’m not sure if it’s really just that easy.

Anyone using a wideband these days? What worked for you? Car is a 94. I use eeHack to datalog.

May 17, 2023 | 07:10 PM

JD1964

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I’ve been using a PLX setup on my Foxbody. If I need a wideband for my Corvette, I would not hesitate to buy a PLX again.

https://www.plxdevices.com/PLX-Wideb...uges-s/125.htm

May 17, 2023 | 09:21 PM

jmgtp

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Thanks for the link, it seems like the sensor also doubles as a narrowband to keep the PCM happy and not have to weld in another o2 bung. Do you know if that is the case in your experience?

May 18, 2023 | 09:53 AM

Orion2011

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From: Shelbyville Kentucky

Quote:

Originally Posted by jmgtp

Thanks for the link, it seems like the sensor also doubles as a narrowband to keep the PCM happy and not have to weld in another o2 bung. Do you know if that is the case in your experience?

Yes, but don't do this. I did that at first on my C6, it's problematic. I finally put the wide band in the O2 bung (gasp) behind the cat and eliminated the that narrowband O2 in the tune.

Yes it works fine after the cat.

May 18, 2023 | 10:32 AM

jmgtp

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I think I welded closed the post cat o2 bung on the passenger side years ago.

I’ve read that the narrowband emulators in the wide bands aren’t the best - presuming that was the trouble in your C6?

Avoiding welding in another bung…. if I just stuck the wide and in place of one of the upstream sensors and ran the thing in open loop while I collect AFR data at WOT, wouldn’t that work?

May 21, 2023 | 08:58 PM

JD1964

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Correct me if I'm wrong but if you run open loop your fuel tables are by default fixed and not adapting to conditions. Since KR can be related to fuel mixture, wouldn't it be kinda pointless to diagnose in open loop?

May 21, 2023 | 09:46 PM

jmgtp

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Open loop is not my ideal way to go about it. I’m looking at the Innovate Motorsports LC-2 which does simulate a narrowband like many others seem to do. This would go against the advice received above, and I’ve read other hit/miss experiences on using the narrowband sim. Yes, I’m avoiding adding another bung. I wish I hadn’t welded closed the post cat bung a decade ago. If the narrowband simulator is that much of an issue I’ll probably pull the exhaust down and weld one in.

All this said, I’m only seeing KR at 95+ kpa, at full throttle where I don’t believe narrowband data is used at all. What I haven’t quite wrapped my head around is how the fuel trims before PE calculate into PE fueling and if I have unreliable narrow band data from the wideband simulator will that mean it will P fuel differently when the regular o2 is back in place?

My sole purpose in the wideband is to tune full throttle. The rest I can tune without and I’m generally happy with my MAF tables. But I’m at a complete guess as to what my PE fueling AFR is and I know my tune is weak in this area, since each time I add adding fuel in small increments it seems to add power and reduce KR.

the wideband will be a temporary install as a tuning tool.

May 27, 2023 | 12:19 PM

jmgtp

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I went with an Innovate LC-2 installed behind the drivers side car where I had a bung that had been capped. Very easy install and did my first datalog with wide and data, worked perfectly and definitely gives me insight on where to adjust my fueling.

I did read the post cat install will have it show a point or two leaner than actual.