Help! 72 duster 318 Wont pass emissions!

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Dusty17

Dusty17

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NJ, USA
I know it doesnt exactly sound surprising, but regardless i need to get my Duster through inspection. Its a 72 318 with a 4 barrel. The legal limit for hydrocarbons in jersey is 500 units. My car failed with over 1500! Originally my engine had just 2 breathers and no pcv valve so i got one and installed it right and it worked great. Did a spark plug, oil, oil filter change and ran it a few times over the course of a week, then went back and as it turns out my emissions got WORSE. Any suggestions? Thanks in advance.
-Joe
 
might sound silly but i used a small HHO system to get my buddies 83 toyota fj60 to pass. Pior to that he had to buy stickers.
 
Turn down the idle mixture screws until the engine starts to run rough, then back up a quarter turn. Then try the inspection again. If you fail, take it outside in the parking lot and turn the screws another 1/8th closed and retest. You may have to do this a few times. Watch which direction the emissions are going with each adjustment and adjust the screws in or out based on results. You should be able to pass. Good luck!
 
Arent 72 models emisson exempt? 68gtx did you buy wheels from me?
 
tekslk said:
Arent 72 models emisson exempt? 68gtx did you buy wheels from me?
Click to expand...

Yes I did. I love the wheels! Thanks!

No, even my 1967 Barracuda had to do the emissions test. But if it fails miserably, I could just get QQ plates and then be emission exempt. But then NJ would limit the cars usage to just car shows and repair stations. NJ used to have a a triangle shaped inspection sticker that would do all inspection items except emissions, as long as you drove the car less than a certain mileage each year. I don't know if that program still exists since the only inspection item left is emissions.
 
Retard the timing a few degrees, that is take some advance out of it. Make sure it has no misfiring going on. Take caution when adjusting the carb. If you lean it out too much you will cause a lean misfire & the emissions will go up. Adjustment should be made(for emissions purposes) on a Exhaust Gas Analyser for best results. Find a local shop that does exhaust gas analysis emissions testing.
 
Does your car have a bigger cam in it? I would say advance the initial timing some, raise the idle and lean the mixture screws. Does nj do a two speed test, 2,500 rpm and idle, or just idle emissions? I would do a compression and leakdown test if nothing you try works.
 
When CT used to do the sniff test my basic routine to get my well worn 318s and /6 was:

a) Lowest octain possible.
b) I container dry gas.
c) Run on the road for 1 hour before testing.

This all assumes:

a) non-vacuum and vacuum advance spark curve where set correctly.
b) car was running on the idle circuits.
 
It is very hard with the new standards to a 1996 or older vehicle to pass in New Jersey, that is why I have QQ plates on my Duster. No inspection required
 
If it is stock and in good condition a 318 should have no trouble passing emissions. When you install a big cam and aftermarket carb is when it gets tough. I tested my 72 318 challenger with 120,000 miles it had way less than the 220 ppm hydrocarbons allowed for 1982 cars when emissions just got started here in pa.
 
Advancing the ignition timing may contribute to higher HC & CO readings. If anything, assuming it's set at least near correct, You want to RETARD the timing a little to get the exhaust gases hotter. High HC readings is an indication of unburned fuel & can be caused by a mixture that's too RICH or too LEAN, or a misfire. High CO levels indicate incomplete combustion from an over-rich mixture. To accurately diagnose the problem you need to post the complete report including: HC, CO, CO2 & O2 readings. You need to know what's going on before just diving in & making adjustments. Otherwise you may make several trips to the test facility.
 
I'm in Sussex, NJ and work in Ogdensburg. Where in NJ are you? I have access to a 5-gas here at work and would love to help you get it to pass.

Mike Holler
[email protected]
 
Thank you guys, DFX340 i think i might try that out if i cant find a big fix because i do realize that a carb adjustment is kind of a longshot for a problem 3 times above the emissions limit. Thanks all for the responses. ill get back to the thread as soon as i get to re-inspection. wish me luck!
-Joe
 
I just went thru NJ emissions today. Failed the first time and passed after retarding the timing about 5 degrees. Here are the numbers for my 1967 273 engine with about 100K miles:

Fail:
Timing = 8 deg BTC
Idle = no tach, so can only guess. Just above stalling out.
HC = 2,434 (Pass <1,400)
CO = 1.52 (Pass <8.50)
CO2= 7.6
O2 = 9.1


Pass:
Timing = 2.5 deg BTC
Idle = no tach, so can only guess. Just above stalling out. Added a few RPMs from previous.
HC = 1,089 (Pass <1,400)
CO = 0.98 (Pass <8.50)
CO2= 9.9
O2 = 6.6

Maybe this info will help one of you.
 
Yup. One big recurring factor with all the "smog" engines was RETARDED SPARK timing. Some were initial AFTER TDC!!
 
When my brothers car had to do one of these, we ended up leaning out the idle system to a point where it barely ran and they were happy with that - go figure. It was a Holley carb, depending on how they do it where you are - get a smaller carb, little jets, make it run a bit lean - should be good.
 
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