failed state inspection....WTF????

[jova1993cb]

well, I went to have the good ol' texas state inspection done today and damned if I didn't pass. everything passed except the nox test. the test results say on the high speed nox part failed cause the current reading was 1695 ppm. the standard reading is 910 ppm. she passed last year with flying colors. I figure the O2 sensor and/or the coolant temp sensor is to blame. I am gonna check tomorrow to se if there are any cel's popping up. anyone have this happen and if so got any ideas?

[TypeG]

try cleaning the egr ports. later.

[10thcb7]

you must live near a big city or something ive never had to get the nox test

[ATS666]

High Nox means combustion temps are too high.
egr is not working or running lean or timming is too far advanced.

What were the other readings?

[92bently]

all readings are really needed to be able to help....prolly an egr issue thou...

[YK86]

I would place my bet on clogged egr ports as 4th gens are bad for that. We have emissions testing here too and every 4th gen that I've worked on that failed (including mine, probably 6-7) had badly clogged egr ports.

Example (my 90 EX-R)
failed nox 5 years ago with a reading of 1620ppm (max allowed 1089ppm)
after cleaning egr ports, I took it in right away and passed with reading of 380ppm.

Every year after that, it's had anywhere from 7 to 40ppm.

Friend's car was almost identical. Failed with 1400, after cleaning, passed with 620ppm.

[radiuslight]

try cleaning the egr ports. later.

Clean The whole EGR system....EGR valve...EGR ports.....trottle and cylinders....seafoam dat motha!

High Nox means combustion temps are too high.
egr is not working or running lean or timming is too far advanced.
What were the other readings?

I would place my bet on clogged egr ports as 4th gens are bad for that. We have emissions testing here too and every 4th gen that I've worked on that failed (including mine, probably 6-7) had badly clogged egr ports.

Example (my 90 EX-R)
failed nox 5 years ago with a reading of 1620ppm (max allowed 1089ppm)
after cleaning egr ports, I took it in right away and passed with reading of 380ppm.

Every year after that, it's had anywhere from 7 to 40ppm.

Friend's car was almost identical. Failed with 1400, after cleaning, passed with 620ppm.

Well I took the clean air car coarse and did smog testing on my CB.....trust me my EGR was bad and it still passed.......it was close to the limit!
Probably with time a bad EGR will make residue build up and that will make it fail!

I recommend before a Smog test always.
Get a major tune up and service the EGR system!!
Spark plugs,distributor cap,rotor,oil change and pump 91+ gas and run it on the freeway awhile then when your about to get it smogged ......go around the block in second gear at 3000-4000 RPM....your converter will heat up and burn more emissions.
There is one last thing I want to recommend.....if there was high nox and carbon flowing by the o2 sensor it is probably dirty as hell and its readying slow and at higher temps...so service it by cleaning the tip by removing it!

[jova1993cb]

ok, here are all of the readings on the result sheet;

Standard Current Reading Result

HC (ppm) 127 15 Pass

CO ( % ) 0.71 0.01 Pass

CO2 ( % ) 14.5

O2 ( % ) 0.2
Nox (ppm) 910 1695 Fail
Dilution ( % ) >6.0 14.5 Pass

These are the readings for the high speed emission results.

[93F22A6]

take put premium fuel in her a octane booster and it should pass it worked on a 85 cutlass but who knows

[jova1993cb]

I almost forgot the low speed emission results so here they are.

Standard Current Reading Result

HC (ppm)132 20 Pass
CO (%) 0.73 0.03 Pass
CO2(%) 14.6
O2 (%) 0.1
NOX(ppm)1006 997 Pass
Dilution(%)>6.0 14.6 Pass


and today I replaced the O2 sensor and the coolant temp sensor. I am hoping that helps some and as soon as I get time I am going to clean tne egr valve ports. I did a recent tune up so I believe I am good on that.

[jova1993cb]

I filled up with 93 octane and a bottle of seafoam tuesday. that was also the day I had the inspection. I kinda think that helped it fail before I worked on her today I jumped the cel connector to see if any codes would pop up. the check engine light stayed on and didn't flash. I disconnected it and tried again and the same thing happened.

[93F22A6]

well shit then, you could possably get a new cat but that would cost a lil

[radiuslight]

I filled up with 93 octane and a bottle of seafoam tuesday. that was also the day I had the inspection. I kinda think that helped it fail before I worked on her today I jumped the cel connector to see if any codes would pop up. the check engine light stayed on and didn't flash. I disconnected it and tried again and the same thing happened.

Well I meant to clean out the EGR Ports,EGR Valve,Throttle and cylinders with seafoam.......not pour it in the gas tank!

I think your gonna have to get in there with a tooth brush and seafoam!

[jova1993cb]

I know that much. I figured that putting it in the tank would be fine for now. I guess I have a job this weekend.

[helofast]

When I had to see the state referee I had the same problem.

What I did is changed the thermostat (because the inspector said that the engine seemed to overheat at the higher temp)

And I cleaned the EGR ports

I also used some additive called "Guaranteed to pass" im not sure if this really helped tho

It passed with flying colors