MatthewBouchard

iTrader: (2)

Was recently tuned a few weeks ago via uprev on a dyno. Since then I have been throwing p1273 every 15-50 miles. I have found that when data logging with cipher that the tune keeps getting richer. After I reset the ECU, the idle is 14.7-8 and runs great for a few minutes. Then the idle goes to around 14.4, then 14.1. Once the code pops it shows - 7-9% short term fuel. While the long term stays a 0% for Bank 1.

The shop that tuned me now whats to do a 2 hour diagnostic on my electrical system. I would like some opinions on what this sounds like, sensors,tune,leaks(shop checked for leaks already),ect.

0jiggy0

iTrader: (13)

Bank 1 air fuel sensor may be going bad and getting lazy sitting on the lean side. Making the car dump fuel since it thinks the car is running lean even though its not. Swap both banks air fuel sensors and see if the code changes to the other side.

MatthewBouchard

iTrader: (2)

Well, I was going to switch them today and before I did I checked the code(s) again. P1283 was also showing now. Reset the fuel trim, p1273 came up and after driving a bit more with p1273, p1283 comes up.

I have 2 short logs from a few days ago that may help with my problem.

bealljk

iTrader: (13)

I dont know your setup or how your ECU is reading O2 but is it possible that you have accidentally swapped the driver side and passenger side O2 harnesses? I only know this bc I did it and it really flipped out my data logging ... tip of the hat to Tcode Tomislav for helping me with this one.

MatthewBouchard

iTrader: (2)

Using the factory widebands to read a/f. I had a shop install the headers so that could be possible. I'll check/sway today and if that does not work, i'll just pay the shop. I'm going crazy with the strong gas smell and sluggish/no power.

MatthewBouchard

iTrader: (2)

Well, I feel stupid .

There was a leak on the pass side between the test pipe and y pipe. I Asked the shop that installed my headers to double check for leaks and had another shop check for leaks and found nothing. I went to test my a/f sensor and felt the leak right when the car turned on. Put in a new gasket and everything seems to be running much better now except B1 idle is richer and hitting high 13's at times(Seems I need the tuner to fix that).

MatthewBouchard

iTrader: (2)

Well, Code popped up again although it took a bit longer. I'm still having the same issue though.. Car gets richer the longer I drive it and once I reset fuel trims everything is perfect for some time. Gonna have a smoke test done and then have the shop recheck the tune. The A/F correction starts to go crazy all of a sudden and then its downhill from there.

Edit: Just looked at an older tune from seymore and the a/f correction were almost exactly alike the whole time. Right now the a/f correction is kinda going everywhere even at idle(and its gets worse as time goes on) after resetting ecu.

MatthewBouchard

iTrader: (2)

Well 99.9% I fixed the problem. I found this thread(thanks to a bump)- https://my350z.com/forum/tuning/5859...-question.html

I never checked the NB o2 sensors due to them being "disabled" but it seems only the 'monitor' is disabled so they don' throw cat related codes. Both sensors showed .28-.29 no matter what load/rpm. I have Berk test pipes that have the o2 extenders and an extra bung; so I simply switched them so the sensor is into the exhaust flow more. Just got back from a 20 min drive and the a/f looks good still.

MatthewBouchard

iTrader: (2)

Just an update if anyone else has an issue like this.
I ended up having a leak near the TB and a leak on the MAF gasket(No idea when they occurred as I switched my intake setup a few times, but they were there). Once those issues were fixed the issue was a lot better, but still there.Bank 1 would still constantly run .5 richer and would be everywhere at idle. Unplugging the 02 sensors in the cats fixed the issue completely.

Battmannes16

So just for some more clarification, You are leaving the downstream o2 sensors unplugged and no longer have been running richer or throwing any check engine lights for running rich? I don't care if this will throw a code for cats as long as my AFR's are normal.

05 35th anniversary with Berk HFC and this has been going on for awhile.

Also, how long has this been a solution for you?
Thanks.

MatthewBouchard

iTrader: (2)

That is correct. I unplugged the downstream o2 sensors and it fixed my issue. I have had no issues since that post with the car running richer/lean codes. Runs like a dream now. I do have 4 codes from removing the sensors(sensor heater), although they don't affect the performance. Hope it works for you as well.

Battmannes16

Just here to update, it seems that this has worked for me! Unplugging the downstream o2 sensors from the car brought the AFR's to normal. Car seems to be running much better now than it did before. AFR's would hang in the 13's after letting off the throttle anywhere in the RPM band and gradually make their way back to 14.3-14.5 at best. Now the response to my Innovate wideband is much snappier and the car finds it way back to 14.5-14.8 much more naturally. No more luggish feeling on/off the throttle and MPG's seem to be much happier. Engine feels overall happier and the car more responsive.

No more having to reset fuel learned fuel settings through uprev every couple of days!

I am also only getting two codes for the o2 sensor circut being low (one in each bank clearly) not four like you are experiencing.

Thank you Matthew!

Battmannes16

And just for anyone coming across this wondering, this has solved my P1273 code that I have been trying to find a solution to for probably around a year now after installing Berk HFC.

Cleaning the MAF, countless checks for vacuum leaks, making sure the exhaust manifolds aren't cracked, and triple checking exhaust connections never gave me any improvements. Do yourself a favor and try this first or at least before you give up. After countless dead ends and threads this seams to be the real "solution" for now.

unplugging the DOWNSTREAM o2 sensors (I just zip tied them up unplugged while leaving the sensors in the HFC) has solved this for now. While I am still getting a SES light for the sensors being unplugged, the car is running flawlessly now.

smellmyz

Does the car pass safety and emission inspections with the O2 sensors unplugged?

jhc

If your O2 sensors are unplugged your "Service Engine Soon" light will light up and that's an automatic Emissions fail.