North American Turbocoupe Organization



Need help passing emissions test
BIG VAM Offline
Member
#1
My TC failed the new TX emissions test -

They now have a dyno test at 1500 RPM and 2500 RPM.

I failed on the NOx - 1350 ppm (1000 std) at low speed, 1810 ppm (1100 std) at high RPM.

Before the test, I installed new Motorcraft plugs, wires, cap, rotor, and fresh oil. Car runs fine.

Any clues on how to get the NOx down so I can get the MAN off my back? I have run one tank of s. unleaded with a good fuel injection cleaner, but have not gone back for the retest.

Thanks, all.

Mike

------------------
No trees were harmed in the posting of this message, but several hundred thousand electrons were terribly inconvenienced...
No trees were harmed in the posting of this message, but several hundred thousand electrons were terribly inconvenienced...
Reply

Pete D Offline
Administrator
#2
See these posts
http://natoubb.turboford.org/Forum1/HTML/004433.html

and see this link; http://www.autoshop101.com/forms/h56.pdf

Other things that may help pass the test are run regular fuel. Cut the timing back to 6-8*


------------------
NATO Member. it's not a vice, it's an obsession
"The nice thing about each new day is nobody ever used it before" Barnaby Jones
88 TC X 2, 86 SVO, mods list at
http://www.turbotbird.com/showroom/pd_88tc.htm
Pete Dunham


Reply

SacsTC Offline
Junior Member
#3
Don't know about TX but in Cal you cannot have timing variance of more than 2* from factory spec and they do check it. Run your car over to Midas and have them check to see if the Cat is heating up properly. Supposedly they will do this for free and it will rule out one BIG possibility. We have the same two speed dyno test and mine also failed miserably on nox

Hey Dan, Have you tried to pass since you got the vam replaced?

[This message has been edited by SacsTC (edited 07-19-2002).]
Reply

Jeff K Offline
Administrator
#4
In order to pass NOx at engine speeds above idle, you MUST have the EGR system operating correctly, and the cat must be in decent shape also. Last year, they added NOx testing to the HC and CO testing here that is done IM240 style on a roller dyno, and LOTS of people have been flunking the test due to old, partly bad cats, and f***ed up EGR systems.

Do you see the EGR diaphram move when you rev the motor when it is warmed up? You should. Apply a vac to the EGR valve at idle, diaphram should move, and motor should run real rough, or die out is system is operating correctly.

------------------
Jeff Korn

88 Turbo Coupe: Intake and exhaust mods, T3 turbo at 20 psi, forced air intercooler, water injection, bypass valve, Ranger roller cam, subframes, etc., etc.. // 86 Tbird 5.0 (original owner): intake, exhaust, valvetrain mods, 100 HP nitrous, ignition, gears, suspension, etc., etc.... // 91 Escort: Bone stock winter car // 00 Windstar (wifes vehicle)
Jeff Korn

88 Turbo Coupe: Intake and exhaust mods, T3 turbo at 24 psi, forced air IC, water injection, BPV, Ranger cam, subframes, etc., etc.
86 Tbird 5.0 (original owner): intake, exhaust, valvetrain mods, 100 HP N2O, ignition, gears, suspension, etc., etc.
05 Taurus SEL Duratec daily driver
04 Taurus Duratec (wifes car)
02 Pontiac Grand Prix GT
95 Taurus GL Vulcan winter beater
67 Honda 450 Super Sport - completely customized
Reply

MUSTBeOffMyBIRD Offline
Junior Member
#5
NOx is heat related and can be caused by higher than normal compression. So go as early in the day as possible for your emissions test. When the ambient temp is 72 and above the inspector is supposed to place a fan in front of the vehicle being tested on the dyno. Make sure this is done.

Vehicle condition is critical. This is the toughest emission to pass because it happens to vehicles that otherwise run well. So make sure your the EGR system works properly and flows. Valve timing or timing belt off marks will hurt. Run higher octane fuel. Set switch to regular. Check cooling fan operation and coolant temperature. An O2 sensor that is slow switching will also cause this failure. The catalyst needs the proper rate of sensor response to provide the cat what it needs to reduce NOx. Lastly I doubt anyone on this board has a problem with carbon build up in the combustion chamber, but if you have higher than normal compression you will have more NOx to reduce.If all this fails to help the cat is needing to be replaced. Good luck and feel free to ask for clarification on any statements.
Reply





Users browsing this thread:
1 Guest(s)



Theme © iAndrew 2018 - Software MyBB