Failed NJ State Inspection, need some help

[EMBPilot]

Hey Guys, heres the short version of the story....


two years ago the inspection was a breeze no problems. This year, not so much...

Drove the car to stretch her legs, did about 10min of highway driving at about 75-80, and another 20 minutes of normal driving. Waited only for about 10 min at the inspection station, cycled the car on and off once while waiting. Car was warmed up well within normal operating temp (about 1/4 up the scale). idling normal steady at 900RPM

This year everything was fine EXCEPT NOx
NOx limit is 1323 the cars reading was 2991 (ouch)

rest of the readings were...
HC 147 limit 173
CO% 0.80 limit 0.98
CO2% 13.3 no limit
O2% 0.7 no limit


well guys.....where do i start....

[Techno Duck]

High N0x is a result of running lean (high combustion temps), which is usually a vacuum leak somewhere. The other possibility is a bad cat, but depending on the mileage you put on the car since the last inspection, its probably not likely. You really need to get the cat hot before it starts working effectivley. Drive the car on the expressway for a good 30 minutes or so prior, then bring it right in for inspection. Dont shut the car off and the faster they inspect, the better.

Dont feel so bad, my 951 failed emissions by about 9x the limit due to rich running conditions.. .

[EMBPilot]

I was hoping youd see this Jon, thanks.
Mileage since the last inspection two years ago is just under 2K, a new cat was installed that year just prior to inspection.

Since that inspection, i redid the vacuum lines, hoses, Fuel pressure regulator, damper, and other intake issues, injectors come to mind... im relatively sure there shouldn't be any vacuum leaks but i certainly will give it another once over.

I just changed the oil, and air filter a week or so ago, fuel filter was done about 18 months ago.
Is there an additive i can add into the tank to assist with the readings? right now its about 1/3 full with high octane fuel
plugs were last done 3 years ago, history of the 02 sensor is unknown.

[Techno Duck]

Ive never used those fuel additives but many seem to have good luck with them. Give all the lines and hoses a good once over. It could also be something like a blown out intake manifold gasket or one of the hoses under the intake. If you have anyone with a smoke tester, that is the most easy way to check for leaks.

[EMBPilot]

Checked all the vacuum lines everything looks secure, even under the jboot.

i wanted to take a look at the O2 sensor to preemptively familiarize myself with it in case someone here brings it up as a possibility.



The O2 sensor wire comes up to the barrel connector that is on the same bracket as the speed/ref sensors. It comes up on the drivers side, RED arrow, then attaches to barrel, and goes into the giant main wiring harness thats secured with the big metal strap, Blue arrow to blue arrow.




Heres the strange part... the O2 sensor white arrow, but running right next to its wire is this connector with 3 pins shaped like a triangle , yellow arrow. I have no clue where it goes or what its doing there.







Im not sure if i should put additive in the tank and drive the car on the highway for 30min and try again. Or replace this O2 sensor, change the plugs and wires and try again. If theres a vacuum issue im stumped because i honestly feel that all vacuum issues are squared away.

I have no reason to believe this is an O2 sensor issue, i simply wanted to post these photos with my findings.

[hpservertech]

Where does that connector go to?

3 years isn't old, but it is cheap to replace, and wont hurt anything by replacing it. Get one for a ford taurus, it's the crossover for these. You will need to cut & splice though.

[EMBPilot]

I ordered Lindsey 1200 wires, 4 bosch plugs (with resistors), and a new O2 sensor bosch from Pelican...

I do not know the history of the wires, plugs or 02 sensor. Except that none of them have been changed during the 3 years ive owned the car. So i figured it wouldnt hurt to get these changed out.

anyone else have ideas here....

[VINMAN]

Funny, I had mine inspected in Freehold this past Fri, and failed for the same thing.
My NOX was in the 1600s didn't get a chance to check anything yet.

I failed for the same thing 2 yrs ago. I tossed that additive in, went back 2 days later and passed.

[EMBPilot]

thanks Vinny, which additive did you use? where did you pick it up?

[EMBPilot]

Few things for today.

I added the CRC Emmisions additive to the fuel tank i'll drive it for a few days...

I changed the wires to the Lindsey 1200 ones they seem like a good product, the ones that i took off looked like the expensive bosch ones as well.

I installed the new plugs, i got Bosch ones but they were only single tipped. the ones i took out look pretty fancy. they seem pretty good, little brown, with some white. These plugs are most likely only 3 years old i think...

can you tell anything by the photos? My uneducated guess is they seemed fine. They all looked identical.

Cylinders 1 and 2


Cylinders 1-4

[Techno Duck]

Plugs look okay, but stick with regular copper, single electrode plugs.

[EMBPilot]

Thanks Jon,
The new plugs i installed are single tipped Bosch super plus.

im going to drive this chemical through the tank on the old O2 sensor. once its through i'll change sensors, take it back over for the inspection. i dont want to risk gumming up the new sensor with the additive....

for conversations sake, why are the 4 tipped plugs not preferred?

[Techno Duck]

My '87 had them for a few months and the car just never ran well with them. They work great on some cars and not so great on others. I personally feel the 944 is one of the later.

They are even more of a problem for turbo charged cars because they retain alot more heat and can cause pre-detonation.

[VINMAN]

Kev, you just need to put in some fresh fuel after you run the cleaner through. Thats the same stuff I used.

[EMBPilot]

thanks guys!
the new o2 sensor arrived today from pelican, i'll swap them out tomorrow and let you guys know the results.

[EMBPilot]

tried heat, tried PB break free.... using a 22mm 02 socket, tried wrenches, I CANNOT GET THE F&(*&$*@# O2 sensor out!

any tips?

next step is to take it to a muffler shop have them remove it.......

[Techno Duck]

I have always had good success running the car up to temp, then trying to remove with a hot exhaust system still. Just be careful you dont burn yourself. I usually cut the wire so i can slip a boxed end of a wrench over it..then give the wrench a couple good hits with a dead blow hammer.

[EMBPilot]

thanks jon, it's warming up now

[EMBPilot]

That worked, warmed it up then hit it again with torch. thanks guys!

[EMBPilot]

one thing i thought of.... if i unplugged the O2 sensor wont that cause the car to ENRICH the mixture, thus increasing CO and DECREASING NOx?! which should balance me out? no O2 being sensed the car will run in a open loop mode, thereby the DME will give it more gas?

i changed the sensor out, got a retest today, and it failed again. However i did not finish the fuel additive, still have 90% of a tank to burn off.

i checked the temp sensor resistance on the outer two pins of the AFM, read 1.65, which is good.

leaves me to
- my unplugging the O2 sensor and returning for another test...
- checking the injectors that were just redone last year by Witch Hunter
- Throttle position switch check? - i checked it per clarks at the DME harness and it checked good.
- ISV is new as of last year...
- i checked the voltage at the AFM, it was good, i did not check the voltage change related to swinging the barn door.

ps. i was told by a friend of mine the state of NJ will discontinue dyno testing next year? not sure if thats true or not...