Grrrr, Failed Smog after turbo swap! Help!

[KenneBell]

Grrrr, Failed Smog! Help Please!

Put the 88 Turbo coupe motor into my 92 stang. I put on a new cat. The guy I went to is pretty cool, he said he would disregard whatever was under the hood if I passed the sniffer. Well Shiitte, I passed everything except NOx. What causes that? Anyone fail before because of NOx, what did they change to pass? Thanks!!

 

[BELL]

how bad did it miss? i'd start with a good tune up with motorcraft parts, plugs, dist cap and rotor. Check the timming and egr valve. CA smog in the bay area sucks. mine failed the other day on HC's (cat is probably shot)...

 

[Dan P.]

might want to get the cat good and hot before you have it tested next time

 

[BELL]

hmmm good and hot means i can go really fast...right...

 

[KenneBell]

Good and Hot, just how I like my women, lol! I think it is the EGR, the the EGR has a restrictor if I remember right. It narrows the egr inlet to about 1/8 inch hole at the back of the manifold. I figure this hole is plugged with carbon and maybe if I clean that out it will do the trick. Already have complete tune up done.

 

[Brantley]

NOX is a byproduct of high cylinder temperatures... make sure your EGR is working.. I know y'all know what EGR does, HOW it reduces NOX is by effectively reducing the cylinder's displacement with unburnable exhaust air.. there is no/very little oxygen left in the exhaust after combustion, so it won't reburn. Less burnable mixture = cooler temps = lower NOX. So... I'd just make sure the whole EGR system is in good working order with no restrictions, and I would think you should be ok.

 

[towbar]

I dont know what the min standards are in Ca, but here i passed without the egr even hooked up. It is on the car but only the exhaust pipe is connected. Not saying that this is not the problem. The first time i took it the car failed big time. I didnt check the timing before I went, but somehow my timing got to around 15*. I adjusted the timing back down to 10* and took it back and the car passed with ease. Too much timing will cause combustion temps to go up creating more NOX.

Just from my experience.

 

[65ShelbyClone]

I can't really add anything to the EGR recommedation.

The emissions limits for this wonderful state are:

15mph: HC 138ppm, CO 0.85%, NO 1148ppm
25mph: HC 113ppm, CO 0.65%, NO 978ppm

The only part mine was borderline on was HC. Mine just squeeked by at 138ppm.

 

[KenneBell]

I PASSED!! WOOHOOO! I cleaned the egr and disconnected the spout so the timing stayed at 10 degrees, disconnected the FPR so it would run rich and cool the cylinders, and passed with flying colors! Thanks for everyone's help.

 

[65ShelbyClone]

Really? What were the measurments?

 

[KenneBell]

15mph C02=15.2 02=0.1 HC=14 CO=0.01 NO=240

25mph C02=15.2 02=0.0 HC=62 CO=0.05 NO=81

 

[65ShelbyClone]

Damn, thats a clean car!