Best to do one thing at a time.
See what B2 S1, new sensor does for you.

 

O2 sensor arrived, I did exactly what you said.

ALL back to normal, SUPER easy..!

$13 repair, 5 minutes. :grin:

 

The units on fuel trim values are percent, and can be positive or negative. Positive means it's adding fuel relative to baseline, and negative means it's reducing fuel. From what I've gathered, "normal" is up to +10 or +15% or thereabouts. A CEL gets set at around +/- 40%. They usually drift positive, meaning the ECU is adding fuel from the baseline value. This is usually due to un-metered vacuum leaks. Un-metered = leaks downstream from the AFM or MAF.

Edited: Add'l details

 

You have a rich exhaust, go lean command, eXtra fuel, out of ECU range (4CYL. is +/-20% not sure on V6) . You have a fuel problem if it isn't 02. I doubt both 02 sensors are bad, but they may have been ruined by the extra fuel dump. High fuel pressure, leaking fuel pressure regulator on rail, leaky injector. Work upstream (intake) easy part check and move down. After each check disconnect battery and wipe for KAM (keep alive memory) LTFT. Drive and look at trims, STFT is present, LTFT is over entire time.

Again 02s check since all codes relate to them. Also check connections. If it is your 02 what caused both to fail? And it's upstream 02 for Fuel trims.

Stft is + at initial startup, to warm engine. when closed loop engine is at operating temp only idle, full throttle open. Is your ect temp okay? May affect closed loop reason for extra fuel dump trying to "warm" engine. What's your idle.

All diagnosis before you condemn a part.

 

Wonder if it's a faulty fuel pressure regulator:
http://www.toyotanation.com/forum/1...2003/430702-1mz-fe-bank-2-misfires-p300-p302-p304-p306-solved.html#post12571130

 

I'm always trying to learn about and understand fuel trims. It seems more an art than science.

To my understanding a zero is perfect stoichiometric balance of air/fuel combustion based on factory baselines. If you see zero that's a perfect world. Fuel trims at + or - is the feedback to the ECU from the O2 sensors that the mixture is off and needs to be adjusted. Since the computer can only adjust fuel then adding or reducing fuel injection is the method to get to stoichiometric.

I have a scan gauge on my Ford Ranger. It gives me continuous LTFT readings on the banks. I hardly ever see zero. At startup you'll see a rich + mixture as you would in an old carburetor setup with the choke on. At acceleration you'll see + values because that produces better HP. My values vary on B1 and B2 most of the time, but can be the same depending on conditions - the values are constantly changing. I usually run about +/- 1 to +/-4 on each bank, independently. So for instance a common reading would be +.78 on B1 and +1.56 on B2 - but nothing to worry about.

The + or - 10% is, as I understand it is within range of a good running engine and allowable.

 

So your around 13% now for both banks LTFT?

 

Long-term for both, yeah, about 13, now.

Yeah, after I switched out Bank 2, O2 sensor 1 now that bank performance mirrors that of bank 1.

I suspect it's still high but NO CODES, and that's what I need to pass my smog in a couple weeks.

But after I pass the test I'm eager to swap out the upper and lower air intake gaskets.

And if you think I should also do other stuff to get both those LTFT down some more, then I'll do that, too.

I'm a noob but I like this very much, I find.

 

13 is OK but not great. add short and long terms together to get a more accurate number. if it's still > +10 do plugs/wires/rotor/pcv stuff as in normal maint stuff to bring it down, along with maf wire, intake, tb, iac and egr cleaning as applicable.
having no codes is only part of the equation. are all 6 monitors 'ready'? if any are incomplete, you still might not pass depending on where the check is being done and other factors.
tony

 

" ]if the fuel pressures you observe are] still > +10 do plugs/wires/rotor/pcv stuff as in normal maint stuff to bring it down,"

Hmmm..I understood almost all of that except for "rotor" --what is this..? :/

 

i dunno what ignition system you have but if you have a distributor cap, you have a rotor cap inside of the distributor cap. now, if you have coil on plug, you don't.
to cut down on confusion, just do a major maintenance service and replace all the stuff the glove box owner's manual says to replace, along with intake and egr cleanings (which there are multiple video's on and also stuff in the stickies on how to do these), that'll probably bring down the trim numbers to within normal range.
tony

 

I've been getting a steady 12-14 on my 1998 V6. I'm going to tear down it this week to do the knock sensors and spark plug misc stuff. I'm hoping this will lower the LTFT and STFT.

The car that the OP has is COP setup, no dist cap.