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

[frohboy33]

Let us know how it goes. From my research these are some things to check for your symptoms.

Intake air leaks
Incorrect Fuel Pressure
Injector valve defective or clogged
Engine Temperature Sensor defective
EGR valve defective
Secondary air leak
Fuel evaporation control system defective or leaking.
Air Mass Meter defective
Vacuum leaks
Oxygen sensor aging (slow response)
Clogged or damaged catalytic converter

[feniks]

ok, thanks man. it's a work in progress (since before winter), i see this car mostly in evenings and weekends so it takes time.

thanks for the list, i'm still looking for vacuum leaks and confirming some pressure readings. so far i found incorrect throttle linkage setting (throttle adj screw was touched in past) which causes the throttle plate to stay open at idle. will try fixing it today as well as making sure the throttle opener works (now it's too far to push the linkage after engine shut off).

rear o2 sensor is on its way. will change in a week or two.

one thing worries me, my car is supposed to be California emission specs, but my IAC valve does NOT have the port for Air Assist tube, at least i cannot see the tube, nor the port.
i need to check if back of cylinder head has the Air Assist port. so far seems like someone used wrong throttle body and IAC to rebuild the car after major accident in past (before previous owner).

despite that i think i will have to take a closer look at EVAP and EGR systems. my fuel cap no longer makes the "psssssst" sound when opening it (it used to do it in past). last time i fixed it by replacing only the fuel cap gasket, this time it might be something else ...

[feniks]

hello people,

did some more tests (after adjusting the throttle plate) and so far vacuum readings are ok. still situation with Long Term Fuel Trim is getting worse, highest readins of LTFT i've seen was +25% (now sitting at +19). total combined (short + long trims) i've seen highest at +30%, only 8% below triggering the System Too Lean error code (P0171). it happens only at closed fuel loop though.

also checked egr modulator filter, hoses and egr valve operation (car stalls at idle when i push the valve up).

i decided to replace both front a/f and rear o2 sensors.. i think both of them are shot as A/F stick to 3.23-3.29V range at idle and barely moves when i race engine (lowest i've seen it was 2.74, highest 3.74V at various tests).
and the rear one has a tendency to veeeeeery slowly fall into close to 0V values, so for most time (~90%) it sits at very low (lean) values just like there was massive amount of oxygen in exhaust pipe at idle.

pics, graphs and dataframes were all posted at toyotanation here in this thread (getting long and heavy):
http://www.toyotanation.com/forum/showt ... 280&page=6

on Monday (day off at work) going to the muffler shop to check exhaust for leaks (they did the flex pipe 3 months ago).

[feniks]

also, i'm still in deep woods with locating the californian Air Assist air tube on bottom of throttle body and cannot either find the other end (i cannot see the tube too) where it plugs into cylinder head by fuel injectors.

anybody has pics of Air Assist tube ('00 gen1 solara 5s-fe california emission) installed on back of the engine cylinder head ? where are the ports exactly ?

[feniks]

ok, some things cleared up. california spec'd 2000-2001 Solaras (and camry) have NO air assist tube connecting IAC valve and back of cylinder head like camry '97-'99 and '99 solaras used to have.

also it seems i got no vacuum leaks after adjustment of throttle plate position, so it fully closes at idle.

checked EGR and it works fine, EVAP is probably OK as VSV runs OK, no error codes.

checked all engine for air leaks when idling and spraying wd-40 al over air/vacuum connections and found nothing.

replaced both oxygen sensors (front a/f and rear o2), ran sea foam treatment through car and still same >+20% LTFT.

yesterday tested engine compression and results are not bad, maybe a little too much carbon deposits in cylinder #2 and a little weak cyl #4, but it looks good.
after cranking (with EFI fuse disabled and throttle jammed open) for about 7-8 revs (this is actually 4-5 secs) i got:
1) 202-203
2) 210-211
3) 205
4) 197-198

I think i will open the crankcase and meaasure valve clearances this weekend. perhaps i have an internal intake/exhaust leak on valves.

also I am planning to return to OEM fuel filter as since 8k miles car was running on crappy cheapo fuel filter from local shop (unknown brand, Champion probably). perhaps it is clogged a bit and is restricting fuel flow at idle ?

I may need to run another Chevron Techron treatment for injectors after replacing fuel filter.

I need to check the ECT as well, perhaps culprit is in electronics.

I hope to find it soon, as 20-22 MPG on mostly highways is killing me!

[frohboy33]

Seems, like you've checked almost everything. You said your year doesn't have a MAF but does have a MAP. I'm not familiar with the MAP readings, but have you checked to see if that is within spec?

[feniks]

yup, items on list are almost all checked.

recently i put some facts all together and it seems the culprit might be in fuel system and I even more suspect the cheap aftermarket fuel filter.


1) my MPG problems started a few weeks after first tune up on car (new plugs, wires, air filter, PCV valve from autozone and el cheapo fuel filter from local shop. since that time i replaced wires around 4 times (ending up with NGK TE58) and changed plugs again a month later to NGK too (former were Bosch).

2) initially let's say a month ago, LTFT was around +14% at idle

3) after using chevron techron for first time it got worse, going up to +18%

4) while doing the torture test on rear o2 sensor (3 min @ 4k rpm) i felt like something crapped out after 2 mins 15 secs (if i remember correct). I was racing engine with techron in gas tank.
it seemed like pressing on throttle was unable to maintain same engine speed, almost like a fuel cut. during that time engine was having hiccups which lasted a few seconds and almost stalled (i wasn't pressing gas pedal anymore). then all returned to "normal", however soon after i started noticing LTFT going up to 20-25%

5) I really have NOT found any air leaks (beside wrong throttle plate adjustment which i fixed already and a minor leak in valve cover)

after thinking about it i think some crap in fuel system started slowly blocking new (cheap) fuel filter. i made it worse by using techron, i'm pretty sure some crap got loose and clogged filter even more (confirmed twice with techron experiments). third time I used techron LTFT dropped to +14%.

replacing fuel filter with new OEM tomorrow. if that doesn't help at all, then i will start checking on fuel injectors.

as per MAP, i compared its readings (via obd2) with another driver's camry (same gen and engine) and they are almost same (difference of maybe 0.1 psi). i really found nothing that could justify such huge positive Long Term Fuel Trim. i also did some real world measurements with hand vacuum pump on various vacuum ports and it appeared all OK when comparing to other users on toyotanation. i think MAP is OK. may need to test it with multimeter to make sure, but i think it's fine.

[frohboy33]

Good luck, I have the exact opposite problem you do my LTFT is at -14% give or take 2%. I have lexus es300. I took my car to a shop and they tested everything they could. They had the car for over a week and couldn't find anything wrong. The guy said that its still within in spec at 14% and I shouldn't worry about it unless it gets into the 20 range. I still think its to low of number, but I don't feel like throwing money at it when I can't pinpoint whats wrong. Let us know if you resolve the issue.

[feniks]

Good luck, I have the exact opposite problem you do my LTFT is at -14% give or take 2%. I have lexus es300. I took my car to a shop and they tested everything they could. They had the car for over a week and couldn't find anything wrong. The guy said that its still within in spec at 14% and I shouldn't worry about it unless it gets into the 20 range. I still think its to low of number, but I don't feel like throwing money at it when I can't pinpoint whats wrong. Let us know if you resolve the issue.

yeah i feel you man. just returned home from 6hr workout on car - OMFG my back hurts!

BTW, the fuel trims "specs" for toyota are -38%/+38% of total trim (STFT + LTFT)

guess what i found on car this afternoon, nothing! hahaha

i replaced a cheap aftermarket fuel filter with brand new OEM, it took me a while as i had to remove air box (unplugging all sensors and crap) and move aside all the wires and hoses to get access to filter from top.
oh, my i4 has screws on both top and bottom so imagine how fun it was...
anyways new filter did not change anything at idle, however after sea foaming and several techron treatments i wanted to replace it regardless to be sure there is no crap in it.

then i pulled the valve cover and replaced the gasket (was leaking on 3 sides), replaced 4 nut seals, PCV valve and grommet with new OEM ones.
then cleaned top and bottom side of cover with sea foam deep creep to remove a little sludge residue (bottom) and some stains and dirt (top).

in meantime measure all valves (that took me a longest while LOL) and found ... all valves in specs hahahaha (i think i'm going crazy LOL)

after putting all together and warming up LTFT landed ... again at 14.1% funny

only reason still in play might be that fuel injectors are clogged a tad and require more fuel flowing through them at idle and not in open loop (under higher pressure).

i think i will pass on further search for holy grail LOL. everything is in specs or new, everything works like a charm (almost, but that's a matter of time). anyways i learned a lot about cars in recent months, that's a plus

[feniks]

i moved towards another option as the last resort. replacing ECT sensor for EFI.

i noticed some time ago ECU sees a coolant temperature increase at idle while my dash gauge indicator doesn't move up (stays at "norm" half way).

now i'm thinking it might be all caused by wrong ECT readings being fed to ECU at closed fuel loop. i heard it can lean out the mixture if too high ECT is detected. then oxygen sensors pick up lean condition and ECU starts administering "richer" by higher positive fuel trims. it makes sense now.

ordered OEM replacement online @ $47 shipped, this weekend will replace and post back if problem was ultimately solved or still persists.

time will tell. either way i don't think i will check any further on this.

[feniks]

unbelievable :headbang:

replaced that sensor and same thing happens. after a while at idle with fans turned off computer sees coolant temperature growing up until 214F (this i when ECT switch in rad turns on cooling fans), at same time dash sensor shows normal (basically same all the time) and when checking with digital thermometer i get around 184F... WTF ?

is this ECU bad or i got a short somewhere in wiring that occurs at idle ? unbelievable ... :facepalm:

i even went a step further and while cooling fans kicked in next time (ECU sees ECT at 214F), i unplugged the new sensor and checked obd2 to find it shows now -40F, so it MUST be the right sensor ...

any thoughts? i'm open to suggestions :confused:

why is this sensor reading a slow temperature incline (not really a spike) in coolant when all others don't ? i don't understand it. :headbang::headbang::headbang:

[feniks]

quick update. i tested ECU feeding resistors into socket on both running and shut down engine and ECU sees good temperature readings.

also took live measurements of new sensor installed and it matches the graph resistance/temperature for this sensor.

haven't tested the radiator fans switch due to hard access, but it's next on list.

also i have a strange pic of my dash (coolant temp gauge) sender (one with grey connector) sitting on engine right by ECT for EFI (the new one with green connector).

http://img188.imageshack.us/img188/6381/photo0013z.jpg


doesn't it seem like it was sticking out leaving a few threads below it ?

that gauge never shows any fluctuations to normal coolant temperature whenever in range of 180-214F. it does show higher and lower than that (outside that range). not sure if it is related to what you can see in pic.

next idea and also the last thing left on list posted before (regarding fuel trims) was checking the fuel injectors.[/img]

[feniks]

reposting results of fuel injector testing on live engine when using obd2 scanner (PC USB ELM327):
http://www.toyotanation.com/forum/showt ... ost3165904

i haven't taken any screen shots this time as my hands were freaking dirty. some time ago when i was looking for vacuum leaks i sprayed the back of intake manifold and cylinder head (including injectors). by now all that wd-40 turned into oily dirt ...

first of all i reset ECU by pulling 15A EFI fuse, waited around 5 mins and fired her up. i wasn't running the scan tool yet unfortunately but noticed that for good 2 minutes car was holding low rpm range like 400-600 and jumping from 400 to 600 and over over again. by the time i connected obd2 it all smoothed out and showed usual results (~700 rpms and so on).

0. this is sample data frame when running engine shortly (few minutes) after ECU reset.

04/20/2010 18:47:21
Calculated Load 27.45%
Engine Coolant Temp 177.8F
STFT 0.78%
LTFT +17.97%
MAP 3.92psi
RPM 699
VSS 0mph
Spark Advance 6.5 degrees
IAT 75.2F
Absolute Throttle Position 12.16%
O2 bank 1 sensor2 0.09V
o2s12 short fuel trim 0%
o2s11 equivalence ratio 1.00 lambda
O2 bank 1 sensor1 3.29V

1. after unplugging fuel injector #1

04/20/2010 18:50:14
Calculated Load 32.16%
Engine Coolant Temp 190.4F
STFT +17.19%
LTFT +25.78%
MAP 4.79psi
RPM 710.25
VSS 0mph
Spark Advance 5 degrees
IAT 71.6F
Absolute Throttle Position 12.16%
O2 bank 1 sensor2 0.05V
o2s12 short fuel trim 0%
o2s11 equivalence ratio 0.98 lambda
O2 bank 1 sensor1 3.15V

total fuel trim = +42.97%

2. after unplugging fuel injector #2, this one may be dirty

04/20/2010 18:54:23
Calculated Load 31.37%
Engine Coolant Temp 188.6F
STFT +7.81%
LTFT +25.78%
MAP 4.5psi
RPM 693.75
VSS 0mph
Spark Advance 5.5 degrees
IAT 69.8F
Absolute Throttle Position 12.16%
O2 bank 1 sensor2 0.02V
o2s12 short fuel trim 0%
o2s11 equivalence ratio 0.99 lambda
O2 bank 1 sensor1 3.22V

total fuel trim = +33.59%

3. after unplugging fuel injector #3, this one might be in worst condition. this one actually zeroed out STFT while holding LTFT at 24%. I understand this one may be the trim baseline for ECU forcing others to inject more because of this one condition.

04/20/2010 18:57:57
Calculated Load 31.37%
Engine Coolant Temp 194F
STFT +1.56%
LTFT +24.22%
MAP 4.5psi
RPM 694.75
VSS 0mph
Spark Advance 3 degrees
IAT 69.8F
Absolute Throttle Position 12.16%
O2 bank 1 sensor2 0.02V
o2s12 short fuel trim 0%
o2s11 equivalence ratio 0.99 lambda
O2 bank 1 sensor1 3.25V

total fuel trim = +25.78%

4. after unplugging fuel injector #4

04/20/2010 19:11:24
Calculated Load 29.8%
Engine Coolant Temp 208.4F
STFT +22.66%
LTFT +25.78%
MAP 4.5psi
RPM 684.75
VSS 0mph
Spark Advance 5.5 degrees
IAT 69.8F
Absolute Throttle Position 12.16%
O2 bank 1 sensor2 0.04V
o2s12 short fuel trim 0%
o2s11 equivalence ratio 0.99 lambda
O2 bank 1 sensor1 3.25V

total fuel trim = +48.84%

sounds like i really need injectors cleaning & flow test ...
also car went into vibrations (holding same engine rpm) after unplugging each of them. though only injector #3 didn't react almost all to unplugging which is reflected in fuel trims (this one mattered least).
reaction to unplugging injector #2 was weak IMO as well.
seems unplugging #1 and #4 caused most powerful effect in fuel trims, those are in good condition probably.

also this situation of having clean injectors # 1 & 4 means there is more fuel running through them as ECU adjust trims for all based on worst one (injector # 3). basically this way car is wasting fuel on 2 edge injectors (1 & 4)and barely meeting norms (if any) on middle ones.

based on above areas of valve cover and top of cylinder head above cylinder # 1 & 4 will be hotter than middle ones. that would explain why a valve cover seal started leaking in those areas recently (replaced already).
this might actually also explain why ECT is picking up higher temps a little too high maybe because cylinder #4 runs hotter (more fuel) ?
am i thinking right ?

let me know what you think, guys ?

i know now i made a mistake of saying that rich cylinder runs hotter. it's cooler in fact than normal (less air). it doesn't change fact that other 2 cylinders run hotter, making my ECT for EFI sensor see a bit higher temperature (upper norm edge).

anyways, decided to send fuel injectors for off-car cleaning and flow testing service in RC Engineering. will see how that turns out.

the rest seem logical. i hope it works out!

[feniks]

OK, quick update here (i kept posting on toyotanation only for some time).

First of all, RC Engineering confirmed injector #3 to be dirty and with dripping pattern (instead of nice spray). Balance between injectors before cleaning was almost 10% (worst #3 211cc/min vs rest at 230cc/min flow). so no doubts 3 cylinders were wasting some fuel afetr ECU was compensating for it.
Injectors after cleaning have 0.9% balance, MPG improved slightly since installation, but it did NOT heal my LEAN idle engine condition (LTFT +20% with regular fuel). i have to dig deeper.

I went ahead to the shop for a smoke test and to my surprise only smoking thing on my car was the EGR Vacuum Modulator, it was blowing smoke like crazy (nothing else did). now, since egr modulator IS supposed to smoke some and no one knows it the amount was right or not I ordered replacement of modulator only because there is a filter in it (was clean anyways) and i want to make sure it's working right.
I understand that actually VSV for EGR may be dirty, sticky and so on, so I will be performing Toyota FSM tests on it soon to confirm it's OK.

Soon I will be about to test the fuel pressure (unlikely reason in my case as trims go back to normal in open fuel loop), however i want to make sure.

Summary:
Intake air leaks - CHECKED
Incorrect Fuel Pressure - CHECKING SOON
Injector valve defective or clogged - FIXED
Engine Temperature Sensor defective - REPLACED
EGR valve defective - CHECKING EGR SYSTEM SOON
Secondary air leak - CHECKED
Fuel evaporation control system defective or leaking. - NO CLUE HOW TO CHECK THAT
Air Mass Meter defective - NO MAF IN MY CAR
Vacuum leaks - CHECKED
Oxygen sensor aging (slow response) - REPLACED
Clogged or damaged catalytic converter - POSSIBILITY

Soon I will run out of things on this check list!

[feniks]

LOL, i found out that someone before me installed filter in EGR modulator upside down. i flipped it over (coarse side up) and fuel trims went down
wrong filter orientation was allowing air to leak into engine.
I still need to check VSV for EGR to amke sure it works OK and doesn't cheat the EGR valve.

also need to replace 1 EVAP hose running from air cleaner box to charcoal canister, it looks bad.

now down to 8-9% on Long Term Fuel Trim. i guess problem solved (<10% is considered good), but i will replace modulator assembly anyways (i want new fresh filter anyways).

I will keep checking EGR and VAP sub-systems, maybe I will be able to optimize fuel trims further down