daddysvet92

I have a 92 auto, and I took it for an emmissions test and it "failed" the NOx ppm.
My car did have a 64 code which I believe is a "lean right oxygen sensor"
First is the code 64 - a lean oxygen sensor?
Second will this effect my NOx ?

The Seven possibles are:
-Inoperative/ineffective EGR system
- Excessive lean air/fuel ratio
-Maifunctioning cats
-Excessive spark advance
-Faulty Thermostatic Air Cleaner system
-Engine deposits or mechanical defect
-Faulty cooling system

Any help would be appreciated!

Thanks
Chris

OkieC4

Yes - Code 64 is the right O2 sensor sensing lean and it can affect your NOx readings as the ECM will try to adjust the injector pulses to enriched the mixture.

Before you start chasing your listed possibilities, you might determine if the O2 sensor has failed. You can do so by swapping the O2 sensor with the left sensor and see if you now throw a code 44 or just replace the right O2 sensor which is not expensive.

Also, check the O2 sensor connector for dirty pins/sockets. The O2 sensor sends a voltage signal from .10 volts (lean) to 1 volt (rich) to the ECM. Any resistance in the wiring or connector will affect the voltage the ECM sees.

UNCLEBILL

Welcome to ONTARIO rules. I just failed the E Test on my 1990. I know my reason...took the precats off and put on a cheap hi flow cat. Just got the new Y pipe with precats and a main cat from C.Central.
To try and help you out; what did you blow on HC and NOX. Since we are both in Ontario; I might be able to help you out. Also how were your idle and 40 km/hr results ?
Bill

Sidney004

This is good advice but having just been through this crap in California, it may be the cats. Post your exact HC and NOX readings.

OkieC4

I'm not discounting a cat problem, but if the right O2 sensor is constantly throwing a lean code, the ECM will widen the fuel injector pulse to give more fuel resulting in an overrich condition, especially at idle... With the ECM dealing with millivolts, it's an easy "first step" check.

daddysvet92

These are the results from the last 3 test:

2007:

ASM 2525 Test
Limit - Reading - Results
HC ppm 57 - 11 - Pass
CO% 0.32 - 0.02 - Pass
NO ppm 421 - 123 - Pass
RPM - 1180 - Valid
Dilution - 14.7 - Valid
Curb Idle Test
HC ppm 200 - 91 - Pass
CO% 1.00 - 0.64 - Pass
NO ppm N/A - N/A - N/A
RPM - 634 - Valid
Dilution - 14.9 - Valid
Overall Test Results = Pass
Gas Cap - Pass

2009:

ASM 2525 Test
Limit - Reading - Results
HC ppm 57 - 0 - Pass
CO% 0.32 - 0.02 - Pass
NO ppm 421 - 132 - Pass
RPM - 1183 - Valid
Dilution - 15.1 - Valid
Curb Idle Test
HC ppm 200 - 56 - Pass
CO% 1.00 - 0.51 - Pass
NO ppm N/A - N/A - N/A
RPM - 679 - Valid
Dilution - 15.3 - Valid
Overall Test Results = Pass
Gas Cap - Pass



2011:

ASM 2525 Test
Limit - Reading - Results
HC ppm 57 - 1 - Pass
CO% 0.32 - 0.00 - Pass
NO ppm 421 - 442 - Fail
RPM - 1203 - Valid
Dilution - 14.8 - Valid
Curb Idle Test
HC ppm 200 - 56 - Pass
CO% 1.00 - 0.51 - Pass
NO ppm N/A - N/A - N/A
RPM - 679 - Valid
Dilution - 15.3 - Valid
Overall Test Results = Fail
Gas Cap - Pass

I hope you can understand this!
Thanks again...
Chris

UNCLEBILL

I would go with the above comment of switching O2 sensors first....reset codes and then see if the right side still persists. A "lean" condition will make the NOx reading go up. Your HC readings are low and if it were the Cat this reading should be high also.
As suggested above; go with the simple check first...switch sensors
Bill

OkieC4

After comparing the 3 test results (07, 09, 11) it appears the emissions have been relatively stable over the past 4 years..

Between 07 and 09 there was a good drop in HC (unburnt fuel hydrocarbons) - did you do a tune up prior to the 09 test? ie. spark plugs, etc?

With the 2011 test, the HC shifted slightly, but the NOx jumped 300. The lean sensing r/h O2 sensor could very well be the culprit for the HC shift by adding a little more fuel and due to the Code 64s I would still change it, but from what I have learned, NOx is driven by higher combustion temps creating nitric oxide.

This large NOx shift could point more in the direction of carbon buildup/sticking of the EGR valve or loss of vacuum to open the valve. After seeing the numbers, I'm leaning more toward the EGR and I would check it as well before the retest.

hooked073

generaly speaking bad nox reading are a failer out the egr system, sure other things can effect it but i would look hard at this system.

daddysvet92

To think back, I did change my plugs as well as put in a new MSD Opti with the vents. So maybe this may have been the result of that. I'm not sure if I had the vacuum line hooked up properly at that time.
Last year my Opti went bad and I sent it back and it was rebuilt. I did change a few things while I was waiting for it to come back.
New in 2010:
- new spark plug wires
- new Knock sensors
- new oxygen sensors on both sides
and I did hook up the vacuum lines to where it showed on the block under the plastic fuel rail covers where the EGR valve lines attach to the block.
Do you think that with the vacuum line hooked up with the same lines as the EGR could this be the result of the high NOX because it might be getting more air from the vacuum line attached to the air intake, thus making it seem like it has a vacuum leak?
I do have a new Oxygen sensor and a new EGR valve as well as a new Coolant tempature sensor too.
With this new info where should I start, I don't mind putting on the new parts but if they are all not neccassary than money saved is money earned.

Here is a picture of what I'm talking about! Hope this helps!



Any further suggestions?

Thanks
Chris

daddysvet92

I did change a few things today before I go for another Emmissions Test!
I tried to change the Right oxygen sensor because of the Code 64, but after I took out the oxygen sensor, the one the store gave me was too short and after screwing it in I culdn't tighten it because the heat sheid around the boltpeice was to high and I couldn't get a wrench on it. So I cleaned both the right and left and put them back in and I'll wait to see if there is another code resulting in an Oxygen sensor.
I changed my Coolant temparture sensor, because the person who did the emmissions test said my car seemed it was running alittle hot.
I also changed my 19yr old EGR valve, looking at the picture I think it was well over do, and because the EGR valve plays a big part in the NOx, maybe this may have been the problem ( I'm hoping ) only another test will determine if this was the culprit, I'll keep you posted on my results after the test.
I also disconnected the Opti vacuum line that tied into the same spot on the block where a line from the EGR selanoid ran into. ( just in case )

I also cleaned all the connectors where sensor plugged into just to be safe while it was apart anyway!

The New EGR valve on the rightand the old EGR valve on the left: The old one was difficult to push in the plunger from the back and seemed to have limited motion.



Wish me luck on my next Test! I keep you posted!
Thanks to everyone so far that gave an opinion or suggestion...

Chris

daddysvet92

Well I went back for a retest and the NOx was lower and the car PASSED ! I also talk with a mechanic at the garage I took it too, and he also suggested to check for a vacuum leak or a intake gasket leak and gave suggestion on how to do this!
Also I did explain to him that for the first time I did use SEA FOAM in my tank of gas and ran it down to almost emty before adding some new gas and bringing it in for the emmissions test. He said that even the SEA FOAM may have played part in the high NOx.
He added that if the car is running fine and without any codes that it isn't something to worry about and he wouldn't suggest spending money to have the garage run a dianostic test for only having a high NOx number - it passed so just check for any leaks and if there isn't any, don't loose any sleep, it's only an emmissions test!
So I got my sticker and I still will look for a leak, but I haven't lost any sleep yet!
So for all those who had sggestions, thanks for all your help!!!!!!

Thanks
Chris