2000 solara se i4 (5sfe) oxygen sensors / fuel trims (obd2)

[frohboy33]

Congrats! Looks like you found the "holy grail"

[feniks]

Congrats! Looks like you found the "holy grail"

hehe, yes! thanks

[feniks]

you wouldn't believe ...

after 2 days of joy problem returned (LTFT +18%) and even replacing EGR modulator with a brand new one didn't help haha!

I did further testing and now it seems (i hope ultimately!) that the VSV for EGR is stuck. funny that ECU didn't pick it up and thinks EGR works fine, while it doesn't trigger when supposed to (exhaust gas not recirculating). that's probably the reason of my whoooping MPG (23 on highway after cleaning fuel injectors haha).

Will replace VSV this Saturday and hopefully this issue will solved finally and for good.

[feniks]

i will not update this thread until issue is resolved ultimately. issue is more complicated the deeper i dig into it.

active discussion on this topic takes place on toyotanation forums (camry gen3&4 section) right here:
http://www.toyotanation.com/forum/showt ... ost3208744

feel free to come over and join over there if you like. thanks.

[feniks]

abandoned the search for a root cause for now.

in the end I was able to beat down the Long Term fuel trim to around +10% (varies depending on weather and engine temperature and other conditions).
there is still a bunch of thing I haven't checked like micro-cracks in intake hose, mini exhaust leaks, internal valve leaks (I have a cam bearing noise on cold engine, maybe this is it).

last thing I did was replacing the timing belt tensioner and resetting the timing belt which slightly improved the fuel trims, but nothing crazy. Worst thing that all this Long Term fuel trim problem was (and still somewhat is) consisting of dozens of smaller issues, each one adding up like 1-2% to the trim .... very annoying.

probably time will tell more on that once the part (whatever it is) fails ultimately and obviously.

[feniks]

OK, 100 miles from replacing the timing belt tensioner (also weather got colder to around 50F during day) the fuel trims got improved significantly.

now reading around +5-6% on Long tTerm Trim and STFT varies (gets worse after driving). seems like new timing belt tensioner made quite a difference in fuel trims

it doesn't mean I have no minr vacuum leaks still haha! especially at idle, but hey, trims are good ... at least in cold weather, so I assume case closed for now. maybe I will think of installing a CAI on this car to keep it better in Summer too

[feniks]

so the Happy End to this thread finally

Car ('00 5s-fe 2.2L) is running back on regular 87 fuel, now running M1 FS oil 5w-30 (with Lucas Oil Stabilizer) and Long Term Fuel Trim at idle is at +5.5% right where it was supposed to be ... it's not ideally perfect, but oh well this car is not perfect either hehe. this is as far as I can make it better without doing valve clearance adjustment and looking for some vacuum micro-leaks around engine.

Took a lot of effort and cleaning/fixing a multitude of minor things to get there ...

here's a proof:


The whole story (39 pages!) has been described here if anyone bored enough to read it haha!
http://www.toyotanation.com/forum/showt ... p?t=333280

[solara90]

very nice, trouble shooting these conditions can be a real pain. What OBDII software are you using?

[feniks]

very nice, trouble shooting these conditions can be a real pain. What OBDII software are you using?

thanks

the software is called ScanMaster, running on a Chineese obd2 clone interface (generic ELM327 clone from ebay), connected via USB to a netbook.

[feniks]

updating as promised once fixed and confirmed

former fix was not holding and fuel trims were still fluctuating from being nice right after warm up and turning out awful after some driving. now it's all fixed ultimately and holding!

issue were fixed for good

it was a few more minor vacuum leaks (leaking distributor plug became a major one recently and went for so long unnoticed, also and few more vacuum hoses around engine were cracked at ends and required replacement) plus fuel system reacted nicely to 24oz of Techron concentrated cleaner in tank (must have been a tad dirty before reaching the injectors)

new LTFT is +3.1% and it holds at idle nicely for last 2 weeks