ls1tech.fan

iTrader: (6)

So I went to get a smog check (test only station) and all levels were great except the NO measurement:
15mph max 414 I got 880
25mph max 701 I got 825

then on the way home got a p0137 code.

Is it my cat or o2 sensor, egr?
Anyone have a quick fix for this? car is stock except for a lid and I don't have the cash for a new converter.

JohnnyWarfare

idk which level it helps fix but i know a few of my friends have ran race fuel to bring numbers down to pass a smog test

Marc3.4V6

iTrader: (1)

High NO I think may be either cat or 02. Hit your cats with a rubber mallet and see if it vibrates like it has sediment in there, if so the cat is probably bad. You can also try a "guaranteed to pass emissions" bottle (it's in a box) found in a parts store to lower your numbers, it has helped me before.

ROCNDAV

iTrader: (100)

Also drive around for 30 minutes or so before going to get tested so your cats are nice and hot. Cold cars run much richer.

mannyman84

iTrader: (2)

What's the year make model?

mannyman84

iTrader: (2)

P0137 HO2S circuit low voltage- bank 1 sensor 2

this shouldn't cause NO to go high, since it only monitors the CAT.

Reason 1: Lean mixture.

Reason 2: defective EGR.

Reason 3: Bad cat

reason 4: bad front O2 sensors

reason 5: a high mileage engine with lots of carbon build up.

XpEdItIoUs

iTrader: (44)

P0137 is saying the output voltage on the driver rear HO2S is reading low voltage (Lean). Causes for this code could be shorted wiring, exhaust leak near the sensor, open in the wiring, high resistance, bad sensor or Plugged catalytic converter. NOX levels are high which is caused by high exhaust temperatures.

Restriction in the exhaust will cause high exhaust temps.

I would first address the code the car is throwing and then address the sniffer problem if still present after the MIL is off. Since know you will fail the obd2 part of the test.

ls1tech.fan

iTrader: (6)

p0137 may be solved:
took the car to get the exhaust checked for leaks (smoke machine)
flange at the end of the cat on drivers side had a small leak
this may have caused the issue with the rear o2 ?

Still wondering about the high NOx when everything else was great (real low)
Wouldn't that mean the cats are ok if only the Nox is high?
Going to do a seafoam next

code came only only the once and after I cleared it has not come back

XpEdItIoUs

iTrader: (44)

You have to drive the car a few cycles for the obd2 system test to complete. Give it a day of driving the car to confirm that the code has cleared. Then check the EGR for clogged pipe or broken vacuum lines. You can take it apart and clean it then do the seafoam. If you have access to a scan tool that can look at PID's, Look the the fuel trims for signs of vacuum leaks that will cause lean fuel mixtures which will cause high combustion temps.

mannyman84

iTrader: (2)

OP if you are around the Hawthorne area I'll be more then happy to scan the monitors and check the fuel trims to see how the car is running.

XpEdItIoUs

iTrader: (44)

Unless the code comes back don't worry about the catalytic converter unless it's clogged or the car is EGRless. Cars with EGR systems don't rely on catalytic converters to reduce NOX levels, only if the car was not equipt with a EGR system from factory it would rely on a 3 way catalytic converter for reducing NOX levels.

musclehead

iTrader: (2)

EGR is emissions related. It's main function is to reduce NOx along with lowering cylinder temperature. If you have high NOx readings I would suggest you look at EGR first.

ls1tech.fan

iTrader: (6)

Just seafoamed the car and added some b12 gas additive
(plugs changed prior to smog test)

Pulled the egr vavle and the pindle moves freely
cleaned it up a little but how do I test it?
I can't find any info on testing the egr


Car used to have a "gas" smell here and there thats gone except for at start up

ls1ya

iTrader: (2)

Let me know if you wanna pass in the mean time.

ls1tech.fan

iTrader: (6)

Just curious:
When I did the seafoam I got smoke from the engine bay also.
Can't remember if it ever did that previous times I did seafoam.
Is that normal or a vacuum leak or something thats causing the high NOX?

musclehead

iTrader: (2)

Your best bet is to find someone on here who has a scan tool.
You can check EGR and O2 sensors. If you are near long beach and available at nights I can help you out with the scan tool. PM me if you are interested.