Emissions FAILED: HC CO NOx CEL

[pillowmaster50]

Long time lurker, first time poster! Big thank you to everyone who contributes to this forum!!!!!!!!!!
Down to business:
My poor 2002 outback just got an F- at the emissions testing place.
Colorado says your check engine light cant be on, and
HC limit is 1.2
CO limit is 15.0
NOx limit is 1.5.
My readings were:
HC = 3.1058
CO = 31.1971
NOx = 1.6596
CEL codes:
P0130 — FRONT OXYGEN (A/F) SENSOR CIRCUIT
RANGE/PERFORMANCE PROBLEM (LEAN)
P0031 — FRONT OXYGEN (A/F) SENSOR HEATER CIRCUIT LOW
INPUT
P1507 — IDLE CONTROL SYSTEM MALFUNCTION (FAIL-SAFE)

It has thrown a plethora of codes throughout its life, but these were the ones it had when i drove it home, after they cleared it at the emissions place. unfortunately, i cant remember any that its had in the past, but i know its never been anything too serious, and never any misfire codes.

I replaced the oxygen sensor, and the neutral switch. (checked and the old switch was faulty, manual transmission, thanks again everyone on this forum!)

I don't have a CEL now for the first time in a long, long, long time. (i always reset the ecu right before i bring it in for testing, but this time it turned on during the test i think because the heater code). the car runs better now than i ever remember! and the exhaust smells like regular subaru exhaust now, instead of burning rubber- horray. plugs were replaced maybe 3000 mi ago.

anyways here's what worries me:
my poor suby uses oil. sometimes a lot, sometimes a little... e.g. sometimes it will be 1.5 to 2 quarts low in a week, then it will be fine...fine...fine... for a month or two, then it'll be a quart low in a matter of days, then fine...fine..fine... uses a quart in a month... fine...fine...fine... for another month or two...yadda yadda.
needless to say, it's really inconsistent. note also that i put the same amount of miles on it every week. and never drive it hard.
there's no noticeable loss of power, it runs really smooth from idle on up. there's no oil on the ground or burning on the exhaust. once, i took the rear passenger side spark plug boot out (cyl #3 i think). and it had maybe 2 oz of oil on it. never before or since have i seen that though. puzzles me. there's no awful noise coming from the engine, maybe a slight tick on the passenger side, but i have to stick my head way in there to hear it.

been maybe 1000-1500 miles since last oil and filter change and its already due for another; oil on dipstick is filthy yuck yuck. ill change the filter and oil as soon as the freezing wind dies down.

do you suba-gurus out there think that i have a good chance at passing then? my readings seem inconsistent with the cel codes? anyone have experience? ive searched and cant seem to come up with any similar issues on my mechanical problem(s).
looking for feedback/thoughts/opinions.
thanks in advance
p.s. a couple months ago, i followed my sister while she drove the subaru; when she shifted, i noticed black smoke out the exhaust, no white smoke ever... i should follow it again after the o2 sensor change...

[ETC]

If by mechanical problems you mean the fact that it's losing oil, there are quite a few threads on it.

Where yours is going I couldn't say but, it's either leaking out or getting burned through the motor. The smoke could be oil in the cylinders [worn rings or valve guides] or, could be the fact that you were running with a bad o2 sensor which puts the car in a "limp mode" which makes it run really rich. Just the bad o2 sensor could cause those readings so it's possible that the car will pass fine but, it is impossible for us to say for sure without seeing the car.

The oil on the plug boots is common, the valve covers start to leak after 100k miles or so and need to be replaced. Oil on the plug boots for a long period of time will degrade the boot and can cause misfires.

Clean out the PCV valve to make sure it's not sticking and allowing excess oil to be sucked in to the intake and burned off.

If it doesn't pass again or it codes again, post back and let us know what's going on.

In CA you can't reset the codes before you take it in because the car will not show ready for testing, I'm surprised they ignore the ECU telling them that.

[pillowmaster50]

going crazy now
update: (sorry its long, crux is at the bottom)
was driving to the emissions (literally on my way there) place back in nov. (reg. expired 11/10) when the cel came back on, p0420. cleaned pcv, amongst other things-- checked for leaks in intake/exhaust, etc... broke down and got a rear o2 sensor. p0420 comes back. grr. tried everything under the sun while saving for a new cat... finally got a new cat last week which i put in yesterday. check out the old one-- the tube shows just how uncatalytic it really was and explains why the efficiency was below threshold lol--thank god the new cat purchase was justified:



there were zero traces of any of the valuable metals that were once in there; no rattling, no dust that i could shake out, nothing.

so here's whats up now:
yesterday, before i started the cat replacement, i checked the codes for the **** of it and pulled (not in order): p0172 system too rich, p0420, p0456 very small evap leak... (and something else too) darn it!
also i was surprised to see the exhaust system was extremely sooty. like i havent even seen more carbon on a 2 stroke...

crux:
i havent really got the chance to drive it since i put in the new cat, but the little i did, it had much more pickup and power it was really amazing. it was still running rich, so i checked the sensor data w/ my laptop and found two things i didnt like: the coolant temperature was like 190-194F, but the dash gauge was right where it always is.
and:
my spankin' new front o2 sensor is crazy! most of the time, its at 7.995 volts, but sometimes it dips down to 1.4 - 1.5 volts. at idle, while its at 7.995v i can feel it loping a little, and then when it goes down to approx 1.4v the idle noticeably smooths out for like two secs, then it goes back to 7.995/lopey/roughish idle for maybe like 5 more secs before going back down etc. i noticed it develop this behavior while driving the last few weeks..
hmm. so all of that and here's my questions: should i worry about my coolant temp? seems kinda high. and whats the deal with my o2 sensor? has anybody seen/heard of anything like this? whats a normal voltage reading? i thought it was supposed to be like .1 - .9 volts, but then also my rear one is > 1 v (steady) so im confused.
AND WHERE DID ALL MY EXPENSIVE PLATINUM AND WHAT-NOT PRECIOUS METALS GO? i do not want that to happen to my $1000 new oem cat.
thanks for your replies

[pillowmaster50]

bump

[subiesailor]

Originally Posted by pillowmaster50

going crazy now
update: (sorry its long, crux is at the bottom)
was driving to the emissions (literally on my way there) place back in nov. (reg. expired 11/10) when the cel came back on, p0420. cleaned pcv, amongst other things-- checked for leaks in intake/exhaust, etc... broke down and got a rear o2 sensor. p0420 comes back. grr. tried everything under the sun while saving for a new cat... finally got a new cat last week which i put in yesterday. check out the old one-- the tube shows just how uncatalytic it really was and explains why the efficiency was below threshold lol--thank god the new cat purchase was justified:



there were zero traces of any of the valuable metals that were once in there; no rattling, no dust that i could shake out, nothing.

so here's whats up now:
yesterday, before i started the cat replacement, i checked the codes for the **** of it and pulled (not in order): p0172 system too rich, p0420, p0456 very small evap leak... (and something else too) darn it!
also i was surprised to see the exhaust system was extremely sooty. like i havent even seen more carbon on a 2 stroke...

crux:
i havent really got the chance to drive it since i put in the new cat, but the little i did, it had much more pickup and power it was really amazing. it was still running rich, so i checked the sensor data w/ my laptop and found two things i didnt like: the coolant temperature was like 190-194F, but the dash gauge was right where it always is.
and:
my spankin' new front o2 sensor is crazy! most of the time, its at 7.995 volts, but sometimes it dips down to 1.4 - 1.5 volts. at idle, while its at 7.995v i can feel it loping a little, and then when it goes down to approx 1.4v the idle noticeably smooths out for like two secs, then it goes back to 7.995/lopey/roughish idle for maybe like 5 more secs before going back down etc. i noticed it develop this behavior while driving the last few weeks..
hmm. so all of that and here's my questions: should i worry about my coolant temp? seems kinda high. and whats the deal with my o2 sensor? has anybody seen/heard of anything like this? whats a normal voltage reading? i thought it was supposed to be like .1 - .9 volts, but then also my rear one is > 1 v (steady) so im confused.
AND WHERE DID ALL MY EXPENSIVE PLATINUM AND WHAT-NOT PRECIOUS METALS GO? i do not want that to happen to my $1000 new oem cat.
thanks for your replies

Could have saved your self about $500 by just having a local muffler shop weld in a new cat but I digress

[lndshark]

Have you checked for any gross vacuum leaks in the intake tract (i.e., between the air cleaner and throttle plate, intake manifold, vacuum hoses)? Any un-metered air, that is, air that the ECU doesn't know about (leaking) will wreak havoc with the engine management system compensating.

[pillowmaster50]

yeah checked w/ propane for intake leaks.
its interesting that the front o2 voltage (measured by scan tool) does the same thing (fluctuates b/w 1.5 and 7.995 volts) whether or not the o2 sensor is hot or not, and regardless of whether or not the sensor is plugged into the harness or not--this led me to believe its not the sensor, so i checked the harness b/w the sensor and the ecu: no shorts or open circuits. i cleaned the battery terminals and cables and the two negative ground leads.
im starting to think the ecu is bad
any other ideas? anybody ever heard of this happening before?

[pillowmaster50]

does anybody know what the voltages should be (with key on or off) checked at the harness side of the front o2 connector? i cant find any really useful info in the service manual (2002 2.5L outback)
thanks.

[ETC]

This is a pretty good writeup on 02 sensors.

Oxygen Sensor Information

Generally you'll have a heater circuit [2 black wires 12v or batt voltage], a signal wire [may have a .5v signal when sensor is not up to temp] and a signal ground wire [no voltage].

The voltage range should be between .1v-1.0v but when at operating temp it will be in the upper end of the range and will be constantly changing [millivolts] from a fairly fixed point. Meaning, the voltage might be just under .9v to just over .9v.

You had mentioned oil loss and you never commented further on it. If it's not leaking out, it's burning through ... burning oil = soot. Burning oil also can mean destroyed Cat and damaged sensor after enough miles.

If the "new" 02 sensor is also completely black and covered with soot, it may not be functioning properly and causing the ECU to run a rich fuel mixture which just makes the whole thing worse ... burning oil and too much fuel.

Varying oil loss is usually something like a stuck PCV valve, other than that you go to worn rings, valve guides/seals. You can try a heavier oil and some additive to try to reduce that.

Good luck

[pillowmaster50]

Today I got a new o2 sensor (warranty) and got a loaner ECU from a subaru repair place. same deal; the o2 sensor voltage (as per my scan tool) reads normally, but then it will jump up to 7.995 volts eq ratio .999 and then it will go back to reading normally. same behavior with my old ecm and the new oxygen sensor. the folks at "super repair" said that they've never heard of an ecu going bad, for my car, but they also said they'd never seen this behavior. they said sometimes the ecu needs to be reflashed after an o2 sensor replacement (due to o2 codes), and they wanted to charge me $96 to do it. i said no; im a programming major and this seems ridiculous to me.
maybe this is normal? has anybody seen this before? ye olde google turns up very little on this... i guess ill just wait and see if it throws more codes it now.
it sucks when you're tags are expired and you're waiting for your ecu to go to "ready" because every car in your rear-view has a roof-rack and may be a cop.

ETC, i am very grateful for your input

please please let me know if anyone has seen this behavior before!!!!!!
thanks