hello,

i bought the car in may, 2009. i tried twice and failed twice on my emissions here in houston area, last week & this week.

before the 2nd test, i changed
1) oil, oil & air filter
2) replaced flame trap
3) checked and replace most vac hoses
4) cleaned tb & iac
5) checked for vac leak from manifold & injectors by squirting fluid around them.
6) blocked off vac hose to car interior
7) checked & metered air temp sensor, map ssensor
8) pulled off o2 sensor to check engine idle when plugged back in.
9) checked for exhaust leaks up to cat & at o2 sensor.


my first readings:
high standard/actual low standard/actual

hc (ppm) 120/19 pass 124/82 pass
co(%) 0.67/0.10 pass 0.69/.29 pass
co2(%) na/14.3 na/14.1
nox(ppm) 848/1520 fail 937/1984 fail
dilution >6.0 /14.4 pass >6.0/14.39 pass


2nd test
hc (ppm) 120/19 pass 124/25 pass
co(%) 0.67/0.10 pass 0.69/.13 pass
co2(%) na/13.9 na/14.0
nox(ppm) 848/1554 fail 937/1533 fail
dilution >6.0 /14.0 pass >6.0/14.13 pass

bottom line, after 2nd try,
1) my nox went up on high speed, but down on low speed,
2) nox now about the same for high & low speed.
3) both are a little less than double the limit.

the previous owner had been using the k&n air filter. when i pulled the tb off, it was tons of oil junk on there. but i figured what little oil there is, it's burned off.

i just bought a new cat. i didn't see how i could measure the o2 sensor, since it has that special clip and the pins are sealed in the connector--can't reach the pins to measure with my volt meter.

i'm

My '94 944 Regina car also had High N0x readings like yours. The catalytic convertor needed replacing. that solved the NOx problem. However, the old CAT died from carbon build-up from a long standing rich condition. That problem was mostly solved by replacing the 02 sensor, the water temp "sensor" and water temp "sender" (2 different things). There is still an issue with the sensor that I need to fix. Still running a little rich. You will be surprised on how far the NOx fall when a new CAT is installed.

HTH

-Keith

hello keith,
thanks for your reply. forgot about this--i'll put the water sensor (ecu) and sender (gauge) on the meter.

i was afraid that an original rich mixture from a bad o2 or something may have buried the cat.

i went ahead and bought a cat from fcpgroton & an o2 sensor from amazon, an nkg 25003 direct fit for $109 + free shipping.

along with the new cat, is coming an intake manifold, just in case to replace something else.

also to note, the last 2 exhaust bolts in the head are sheared off, but i don't feel by hand anything leaking from the last exhaust port (by the firewall). so, i assume it's sealed.

regards,
byron

thanks & regards,
byron golden
86 245
92 245
94 944

Hello Byron
im guessing the o2 sensor has that funky brown connector, well it comes apart ofter you slide the connector lock thing sideways, might take a little messing with.
that is if'n its the one i think.
good luck
MIke

hello mike,
thanks for your reply.

question: if the o2 sensor is not doing it's job, why am i not getting a check engine light or codes indicating an o2 failure? maybe the obdI is not too accurate? not sure.

i didn't check it, but i went ahead and bought a ngk o2 sensor for the regina system and bought a cat also. hate paying for this stuff.

i'll put them on and try a third time.

regards,
byron