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

[feniks]

hi,

recently started to monitor my car using obd2 PC tools. i started having some doubts about oxygen sensors running right.

can someone name and locate the oxygen sensors on 2000 solara se i4 engine ?

i looked through camry gen4 factory manuals (SFI on camrystuff) and something is not right. is it different on solaras ? specifically i'm interested in type and location of bank 1 sensor 1, is this the one sticking out in the middle of exhaust manifold ?

does anybody know its working voltages ? also is this the one operating short fuel trim (when running closed loop) ?

thanks for help.

[frohboy33]

Not sure the location, but the o2 sensors should be at about .45 volts. What are yours reading? Yes they help control the short fuel trim along with the MAF and some other parameters such as fuel quality. What are your fuel trim levels?

[feniks]

i have no MAF, only MAP (5s-fe engine).

I'm worried about crazy positive fuel trim adjustments in closed loop (at idle or when crusing with a steady speed).

below are 2 examples of data i could log from ECU with Digimoto datalogging. i currently have LTFT at +11.7% after racing with some Chevron Techron in tank. LTFT used to be +14.8% and climbed even higher right after pouring techron into tank.

at idle, "Parked" (closed loop)

02/28/2010 6:31:36PM
Calculated Load 26.27%
Engine Coolant Temp 208.4F
STFT +2.34%
LTFT +11.72%
MAP 3.77psi
RPM 990
VSS 0mph
Spark Advance 10.5 degrees
Intake Air Temp 66.2F
Absolute Throttle Position 13.7%
O2 bank 1 sensor2 0.20V
o2s12 short fuel trim 0%
o2s11 equivalence ratio 1.00 lambda
O2 bank 1 sensor1 3.30V

at idle in "Drive" (closed loop)

02/28/2010 6:08:55PM
Calculated Load 35.69%
Engine Coolant Temp 203F
STFT +0.78%
LTFT +11.72%
MAP 5.37psi
RPM 701
VSS 0mph
Spark Advance 11 degrees
Intake Air Temp 55.4F
Absolute Throttle Position 13.7%
O2 bank 1 sensor2 0.02V
o2s12 short fuel trim 0%
o2s11 equivalence ratio 0.91 lambda
O2 bank 1 sensor1 2.92V

racing engine on "2nd" gear (open loop)

02/28/2010 6:16:30PM
Calculated Load 96.08%
Engine Coolant Temp 192.2F
STFT 0.0%
LTFT +3.13%
MAP 14.21psi (98 kPa)
RPM 5863.75
VSS 68.97mph
Spark Advance 16.5 degrees
Intake Air Temp 50F
Absolute Throttle Position 73.33%
O2 bank 1 sensor2 0.93V
o2s12 short fuel trim 0%
o2s11 equivalence ratio 0.82 lambda
O2 bank 1 sensor1 2.27V

i also suspect an air/vacuum leak from somewhere and maybe an IAC valve getting dirty again. not sure yet how to initially pinpoint it. thanks for looking.

[turboman412]

all camry and solara oxygen sensors are in the same place. open the hood and look at the exhaust manifold. there will be your first sensor there. known as bank 1 sensor 1. your next sensor is after your cat converter. and that is known as bank 1 sensor 2.

if that first sensor is an oxygen or air fuel i dont know, it depends on if your car is california spec or not. eatherway it adjusts your fuel mixture!!!!

Just fyi! if you come up with a lean code it is not always the first sensor. sometimes its the last one! the pezevs are alittle confusing to diagnose. becouse if the last sensor is off it will adjust your fuel mixture (thinking that sensor is correct) it will send the other sensors out of range and put on the check engine light.

v6's have 3 sensors total.

newer camry's called pezev have 3 sensors (4 cyl)

[turboman412]

almost forgot. to help diagnose what is both your fuel trims at?

[turboman412]

i beleave in closed it is running preset config, and in open it is using the sensors to make adjustments.

[feniks]

hmmm, as far as i know in closed loop the first oxygen sensor controls the trims mostly while in open loop there is much more to that.

at idle (closed loop) my trims are (per above datalogs):
Short fuel trim (STFT) +0.78%
Long fuel trim (LTFT) +11.7%

I have no idea what specs my car was built to as the first oxygen sensor sitting in the exhaust manifold looks like it was a Californian A/F sensor and my ECU identifies itself as "California II - ARB".

i compared my solara with both federal and Californian designs with ge4 camry factory manuals (location of sensors on both and air assist tube specific to California only) and it seems I should be federal specs (no air assist tube on TB) while first sensor O2S11 looks like (and behaves per voltage) like it was A/F one. kind of baffled with this.
the second one O2S12 tends to give very low voltage at idle (running lean).

on top of that i have zero trouble codes stored in ECU (not even pending).

i'd like to diagnose the first sensor (in the middle of exhaust manifold) with a multimeter, but first i need to know if that's the A/F or normal oxygen sensor as they give different voltages. i think normal oxygen sensor (non-california) was supposed to be mounted at bottom of manifold while Californian is mounted in the middle. really confused here.

[frohboy33]

Im not a mechanic, but the research I've done would indicate that voltages for your o2 sensor are off. The .20 volts is close for an o2 sensor (supposed to be at .45). This would indicate a lean situation and increase the fuel trim. An A/F sensor is suppsoed to be at 3.3 volts. So your on at idle with that.

[frohboy33]

i beleave in closed it is running preset config, and in open it is using the sensors to make adjustments.

Other way around.

[feniks]

Im not a mechanic, but the research I've done would indicate that voltages for your o2 sensor are off. The .20 volts is close for an o2 sensor (supposed to be at .45). This would indicate a lean situation and increase the fuel trim. An A/F sensor is suppsoed to be at 3.3 volts. So your on at idle with that.

voltage of the mentioned sensor o2s12 varies greatly. it can show as little as 0.01V at idle up to 0.76V at same idle. do you think it's the sensor shot ?

i also suspect having a vacuum leak somewhere, wouldn't it cause the sensor to read such condition if i had an air or vacuum leak ? trying to find some steps on testing all those ports and hoses properly... no luck so far.
i'd like to be sure that no other stuff impacts readings of that o2 sensor before i replace it.

also, you think that i got A/F sensor in front ? i know its location and voltage points to it ... but i thought my car was built to meet federal specs, not the californian ... still confused about it...

[turboman412]

i had a 00 4cyl that was fed and it had an oxygen senser not an a/f. if you pm me your vin i can look it up. here are some pages in a book i have i think you could get some use out of. let me know if you have any other questions. and no i do not think a small vacuum leak is your problem. what does your car idle at? and soap and water is your best option, i have used Windex before lol.

[turboman412]

Hope this helps!

[feniks]

i haven't read all you posted yet (pages).

usually car idles at (warm):

a) Park or Neutral at 1,000rpm with many accessories ON, around 900+/-50 with all turned off

b) Drive, R, 2, L at 700+/-50 rpm

until now I haven't figured out why its idling speed differ greatly on this car between driving vs non-driving gears.

i was trying to confirm oxygen sensor 2 fault as per P0136 Diagnostics troubleshooting (manual Diagnostics, page 77-78 ), no error/trouble codes in my ECU though, i simply don't like its voltage readings in obd2.

this is what i did, i hope i didn't blew up anything (all works still hehe).

...

now, i tried to test oxygen sensor 2 (after catalytic converter i believe) as per Diagnostics manual, page 77 and 78.

CHECK:
Read voltage output of the heated oxygen sensor when the engine suddenly raced.
HINT:
Perform quick racing to 4,000 rpm 3 min. using the accelerator pedal.

OK:
Heated oxygen sensor output voltage:
Alternates from 0.45*1/0.40*2 V or less to 0.60*1/0.50*2 V or more.

now i understood that i was supposed to race the warm engine at 4,000 rpm constantly for over 3 minutes and take oxygen sensor readings with OBD2. well readings for the time of test (around 2 minutes) were not like described. should i assume it is faulty then ? why no error code then ?

now more important question (flame me if i'm dumb), after 2 minutes of racing (park gear) engine started loosing rpm even though i tried pushing gas pedal further to maintain it. it was like it was cutting fuel (sounded more like rev limiter). why did it do it before 3 minutes elapsed ?

was it because the Engine Coolant Temperature ? or maybe fuel pump failing ? no trouble codes displayed as usual (it starts to piss me off, i want an error code!).

test started:
03/01/2010 22:51:39

test finished:
03/01/2010 22:53:45

here are readings before engine started slowing down:

03/01/2010 22:53:45
Calculated Load 23.92%
Engine Coolant Temp 212F
STFT +3.13%
LTFT +7.81%
MAP 3.48psi
RPM 4025.5
VSS 0mph
Spark Advance 41.5 degrees
Intake Air Temp 59F
Absolute Throttle Position 19.61%
O2 bank 1 sensor2 0.58V <- per specs its supposed to alternate between <0.45V and >0.6V (california)
o2s12 short fuel trim 0%
o2s11 equivalence ratio 1.02 lambda
O2 bank 1 sensor1 3.37V

tell me if i misunderstood toyota diagnostic instruction (racing for 3 minutes). anyways as i do not understand WHAT cut the fuel after 2 mins 5 secs all i can say by looking at further datalogs (rpm dropping at same throttle position) the only difference is that mentioned O2 sensor started reporting 0.00V for next 30 seconds - could it be the cause of fuel cutting I experienced ? so is it a faulty oxygen sensor then ?

...

I am also having a thread in toyotanation about my hopeless efforts in order to get the Long-Term Fuel Trim down to reasonable bracket at idle:
http://www.toyotanation.com/forum/showt ... p?t=333280

guys over there are leaning towards a vacuum leak.

[frohboy33]

I am also having a thread in toyotanation about my hopeless efforts in order to get the Long-Term Fuel Trim down to reasonable bracket at idle:
http://www.toyotanation.com/forum/showt ... p?t=333280

guys over there are leaning towards a vacuum leak.

Could also be an exhaust leak. How quite is your car? Are you getting bad MPG.

[feniks]

I am also having a thread in toyotanation about my hopeless efforts in order to get the Long-Term Fuel Trim down to reasonable bracket at idle:
http://www.toyotanation.com/forum/showt ... p?t=333280

guys over there are leaning towards a vacuum leak.

Could also be an exhaust leak. How quite is your car? Are you getting bad MPG.

I had the flex pipe replaced about 3 months ago as well as engine/tranny mounts. it doesn't sound like there was an exhaust leak, but i may take to the shop to get it checked (flex pipe is still in warranty).

my current MPG on this 10 year old 4-banger engine is worse than most V6 engine get. My wife gets now around 19-22MPG while driving mostly on highways (~75%). i believe this number should be around high 20's or even low 30's when only cruising on highways.

transmission was flushed completely at the dealer 6 months ago at 64.5k miles (first time in life of this car).

also the timing belt, water pump and oil seals down to oil pump were replaced with OEM parts about 5 months ago (water pump was leaking). the thermostat is also new (replaced at WP job time).

engine runs a little louder than in past but this could be because of motor oil switch from dino oil to synthetic 6 months ago or maybe i need a valve clearance adjustment job (will try checking that when fixing valve cover in a few weeks). I have minor oil leaks from side and rear of the valve cover, nothing serious. all filters, plugs and wires were swapped with new ones (NGK) less than a year ago.
all works great with this however it still has terrible gas mileage that some times gets better but recently only gets (or stays) worse/bad.

today after work i will borrow a vacuum pump from AutoZone to get vacuum readings of E,P,R ports on Throttle Body at idle and at 2,500rpm.