P0134

[msantana101]

A little background on the situation: Did a BT swap last weekend and when we started it up my AFRs were stuck at 14.85. Previously before the swap, my AFRs were moving around as they should when the k04 was in the car. Fast forward to today: I just swapped the primary o2 sensor with a new one from rockauto (NGK NTK 24393) and it's still having the same issue; AFRs stuck at 14.85. I've reflashed a few different maps and still the same thing. The wires on the new o2 are not twisted and the clips are plugged in. The secondary o2 is currently not in the DP due to messed up threads, so we plugged the bung; this shouldn't be causing my current issue at least I don't think? Not really sure what else there's left to check. I'm hoping it's something super simple, but who knows what it could be. Any ideas on what might be causing the issue? Needless to say I'm very disappointed in this outcome as I can't even enjoy the hard work my friends and I put into the car. This shit is big time lame...


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[gigliotti175]

That's probably your issue. Not having the second o2 sensor in. If I unplug my second o2 sensor it sticks at 14.85. If I unplug the first one it stays at 29.??.

[DVM17]

That's not his issue. I've not had a secondary o2 sensor plugged in for a couple months. got it tuned without it and haven't had any issues.

Unless the ecu's see the secondary o2 differently between gens.

[mrtheandrew]

I thought the primary sensor was pn 24357?

[trf5000]

Genpu 2nd o2 sensor has to be plugged in and in the exhaust stream.

Different logic between the gens. We figured this out awhile ago when guys with pus were having massive problems with defoulers on the 2nd 02 sensor.

[msantana101]

Lumberjack is running his world record pu without a secondary o2 but his is a 2013 and mines a 2010. Would that make a difference?

EDIT: just realized this was posted in the first gen section. Sorry I wasn't able to see that on tapatalk as it was cutoff.

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[Boosted Beluga]

@ms3blackmica; @rfinkle2; @Justin@Freektune;

[ms3blackmica]

I was under the impression that the rear O2 sensor was present.

Mike, I would really try and get the rear O2 sensor in first before diagnosing any further to see what happens.

[Fjager]

I got the same problem with my Dp install, it got fixed with a new sensor, you could have gotten a dead sensor, it does happen.
If anything try and double check all of the wiring harness connections.

[Little John]

Originally Posted by Fjager I got the same problem with my Dp install, it got fixed with a new sensor, you could have gotten a dead sensor, it does happen. If anything try and double check all of the wiring harness connections.

Its not the senor because i am using the one he bought and it is reading fine on my car! I although have my secondary o2 plugged in!

[msantana101]

Originally Posted by ms3blackmica I was under the impression that the rear O2 sensor was present. Mike, I would really try and get the rear O2 sensor in first before diagnosing any further to see what happens.

Nish, I had the secondary o2 connected but not in the stream due to stripped threads on the o2 so it was just basically hanging out in the open. Wouldn't it still read something even outside the stream, or does it absolutely have to be placed into the stream?


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[ms3blackmica]

It needs to be in the exhaust stream.

Having personally seen your car when I was out in Cali and going over the symptoms/issues with Bryce I will say that you definitely need to get that rear O2 in the exhaust stream and see if you get feedback.

[msantana101]

Alright sounds good. I'll give it a go and post up my results.


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[msantana101]

Originally Posted by ms3blackmica It needs to be in the exhaust stream. Having personally seen your car when I was out in Cali and going over the symptoms/issues with Bryce I will say that you definitely need to get that rear O2 in the exhaust stream and see if you get feedback.

So I had the opportunity to put the rear o2 in today and absolutely nothing changed. AFRs were still stuck at 14.85 and I even did a hard reset on the battery and reflashed my map as well. In all honesty I was kind of expecting this but it's better to know for sure than to wonder. At least this came in the mail today so hopefully this will remedy this issue:


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[msantana101]

So it came down to being a bent ecu pin that was causing my AFRs to stay stuck. Fucking wow. I'm extremely happy and relieved now but still cannot believe that was the issue and that it was overlooked for so long. Amazing...

[pdc001]

Do you have to have a pic of the bent ecu pin? I currently have the same problem.

[Boosted Beluga]

@msantana101;

[msantana101]

I don't unfortunately. But it was bent to shit and pushed down.


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[Rileymayo]

Sorry too reactivity this thread, But I seem to be having the exact same issue.. Just did a new catless DP install, And I’m new too the page also.. but my afr was stuck at 14.85, secondary o2 was on & snug and so was the primary but I’m getting a CEL P0134 which is the primary o2 sensor.. it all seems fine but is used and could possibly be dead.. cleaning out all connections & trying again but if this doesn’t work, where would I find a bent ecu pin? Before I go buying a new o2 sensor! Thanks in advance fellas all help is much appreciated

[Witness]

I'm also having the same issue. I bought a new NTK o2 sensor and installed it but my AFR's are still pegged at 14.85. Any way I can do a continuity test on the connectors for me to diagnose?

[MSMS3]

Originally Posted by Witness I'm also having the same issue. I bought a new NTK o2 sensor and installed it but my AFR's are still pegged at 14.85. Any way I can do a continuity test on the connectors for me to diagnose?

Check the part number on that O2 sensor. Gen 1 and Gen 2 are different. OEM is best for the primary O2. I posted a good source on your other thread.

Rock Auto is notorious for getting our parts wrong, often confusing with regular Mazda 3 or confusing 1st and 2nd gen MS3.

[Witness]

Originally Posted by MSMS3 Check the part number on that O2 sensor. Gen 1 and Gen 2 are different. OEM is best for the primary O2. I posted a good source on your other thread. Rock Auto is notorious for getting our parts wrong, often confusing with regular Mazda 3 or confusing 1st and 2nd gen MS3.

do you know what the part number for the OEM O2 sensor is?

[MSMS3]

Originally Posted by Witness do you know what the part number for the OEM O2 sensor is?

Really? I've been generous with my time and thoughts. Perhaps you might want to take the initiative and do a bit of investigating on your own. You can get the part number from any of the OEM Mazda parts stores. Many Mazda dealers operate on-line parts sales. It is easy to look up.

Also, I believe I recently posted a link to the Edge Auto Sports website with the part number. Its right there on your other thread.

Gee, at least try, please? Ok? We get tired of spoon feeding people who expect to have others do everything for them. That's not how it should work here. It's not unreasonable to ask someone to try to do a bit of their own homework, and then if they really fail, to seek help.