AFR Non-op

[Trekker]

Hi all, so my accessport almost always reads my afr as 14.85 but will jump to (no in-between) 29 and sometimes randomly displays 9. No o2 codes present and the only code I have is a p2507 which should not affect o2 readings. Car back obviously isn't getting any o2 reading and gets a loud exhaust pop sometimes. Idle sits at about 800 most of the time sometimes idles at 550-600. Anyone seen this before? Could it be a bad tune causing it? The tune was made for the previous owner and I don't think he ever revised it or anything. It was just supposed to be a safe to start tune. Car does make good power but I'm sure I'm missing some ponies. I should add the car also intermittently runs rough but that shouldn't affect afr reading, if anything it should make it move around more.

EDIT: I fixed the CEL the Engine battery positive fuse was blown so now there is no CEL but it still reads 14.85 constantly. Double checked with torque pro and it reads 14.85 also. No cuts found in the O2 wiring so I'm thinking that it is tuning related as there is no CEL for it and usually when they fail they read incorrectly, not defaulted to 14.85 on most cars i've worked on

[Speed3kid93]

Could be the o2 sensor, but the more likely option is that the connector going to the o2 sensor is bad, and therefore getting a bad reading. I would take the connector out and have the connection checked with a volt-meter.

[mituc]

Originally Posted by Trekker Hi all, so my accessport almost always reads my afr as 14.85 but will jump to (no in-between) 29 and sometimes randomly displays 9.

This is a classic symptom for the primary O2 sensor being shot. take it out, take a good piss on it and them just replace it.

Originally Posted by Trekker not defaulted to 14.85 on most cars i've worked on

Yeah, the mazda ECU likes to be a bit different... The car will still work though but it will entirely rely on the MAF readings (as well as IAT and BARO), so no AFR corrections (fuel trims) will be applied.

[SyntheticAtmosphere]

I 2nd. I had a bad 02 and the AP reading was static at about 14.85 (idr the actual number)

[Trekker]

Originally Posted by SyntheticAtmosphere I 2nd. I had a bad 02 and the AP reading was static at about 14.85 (idr the actual number)

Well I guess that's my first shot then. They are 220 at O'Reilly's which is a bit ridiculous. Found one for to on rockauto. I'll update the thread when I get it in. Do you by chance know if these cars have a problem with crank position sensors? I have a code that comes up randomly and it runs a little rough then goes away.

[Thor Hammer]

Originally Posted by Trekker Well I guess that's my first shot then. They are 220 at O'Reilly's which is a bit ridiculous. Found one for to on rockauto. I'll update the thread when I get it in. Do you by chance know if these cars have a problem with crank position sensors? I have a code that comes up randomly and it runs a little rough then goes away.

Unless the VVT/Timing chain was recently replaced...No.

Change the O2 sensor with the ATK one from RA and then see if the problem persists.