i recently had my car tuned. my fuel trims were perfect as of a few days ago. now im back to throwin a p0712 - bank 1 too rich. there has been change in temps since ive been tuned, but would it make that much of a change in fuel trims? my stft are under 10% but now my ltft are at -25%. the only thing i can think of is that i just changed my manifold gasket, but i didnt have any leaks prior to my tune. i have no vaccum leaks, a/f sensor is brand new so that rules that out. im gonna try takin off my maf sensor and cleaning it since im now running a blow thru setup. other than that im stumped. do any of u think it could be the firmware on the fic by chance bc i was throwing some unusual dtc's and now im not anymore. i was getting a bank1 sensor2 high ckt, and a crank sensor code. idk, im pretty much scratching my head on this one and i really dont feel like driving an hr and half to the guy that tuned my car. could it have been the change in temps even tho it hasnt been that drastic of a change?

 

try this out for a sec...get the car fully warm (maybe drive it around for 10min), park it and let idle for a few min, watch afrs carefully and take note, shut car off and disconnect the batt for a min, unplug the primary o2 sensor,start her up and see what your afrs are.

 

What does this do? And am i unpluggin the primary w the car running or off?

 

Like I told you its going to take a lot of adjustments over time.
Get the car inspected when you can and stop worrying about it.

 

you unplug it before starting the car.

it will tell ya a few things really. If the primary o2 is a little fouled (not a dead sensor but its readings are a little off) and the tune is spot on (tuner tuned for stoich at idle) you should run at 14.7 or around that after unplugging the primary and starting the car.
If afrs instead are hovering around 10-11afr at idle after unplugging the primary then id start looking into the tune (since you said you didnt have any leaks).

you unplug it before starting the car.

 

^ correct

this is a faster method overall

unplug the primary o2 then tune the car to 14.7

plug it back in and the ecu shouldnt have to make any changes (fuel trim)

 

the car is already inspected mike. the only reason im askin is bc i wanna know more about how the fic works in conjunction with the ecu. i also wanted to know if it was possible for the trims to be off as much as they are due to the change in temps. i already got the car to pass inspection so thats not the issue. ill give this a shot and see where im at. if its spot on, ill just deal with the light bein on.

 

I honestly wouldnt worry about it

come buy the springs!

 

lol...dont worry mike...ill come thru for the springs man. i just gotta get some extra cash flow. i should be able to do it next week sometime for sure. even if i give u half this week and the other half next.

 

no doubt

I wouldnt worry about the CEL - you are going to be chasing it forever

 

yea i can tell. its prolly one of those things that will come and go depending on the weather. ill worry about it more next year when im up for inspection again. lol.

 

Ah trims, trims, trims......So much fun.

 

yeah tell me about it paul. could the slight change in temps have caused my trims to be off like this?

 

just get a scan gauge. no more CEL lol

 

temps play a huge factor but it depends on how big the temp change is. when you tune on 100f days then it turns into 40f days you can just hang up that summer tune and put on a winter tune. the fic cannot compensate for weather changes (including temps) that im aware of (and iv been tuning on the fic for over 3 years now if that tells ya anything). However small temp changes (say 5-10 degrees) you should not have a large fuel trim correction based off of just temp. Something else is going on I suspect and thats what im trying to narrow down.

 

Yes. Chris hits the nail right on the head. Temp and humidity will 100% change the trims and make for differences in your tune.

MAP based systems are very prone to this and need to rely on other sensors like baro pressure AND IAT to help in correction. MAF based systems can make changes based on the fly for these changes.

 

When I fouled my plugs I got this same code. It was a cold winters day and I let the car idle too long is my guess. I started driving and the code popped up, didn't think anything of it. Got home trims were off on my datalog, all readings were really rich. I pulled a plug, looked blacker than norm smelt a little gas. Changed the plugs reset ecm, took her for a test drive and did a datalog. Trims were back to normal. To be sure, I swapped out the old plugs again did it over again. Light came back on and the excessive trims came back.

Dang Toyota ECM gets what it always wants! I wish someone would hack it already and shut that dang box up already! The AEM fic piggyback acts like a foreign infection most of the time. I swear you have to have a tune for every temperature. Maybe, Paul can start a donation pool for money to pay a reverse engineer to get some real results out of this ECM!

I know I'm a dreamer but I like to dream big.

 

What I'm understanding from this is If you live somewhere even mildly climatic you need separate tunes based off the weather?


Sent from somewhere using Something.

 

correct.