Not Passing Smog Need Help Please!!!!!!!!!!!!!!!!!!!!!!!!!!

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805moparkid

805moparkid

Slant and AFX Guy
Joined
Oct 29, 2008
Messages
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Location
Anthem AZ
so being my day off i welded in my new cat and prove the piss out of it to get it smogged... cuz i have to here in az!!grr. so anyway it wasn't even close to passing
@ a loaded 30mph roll
HC 349 actual - 450 Max Pass
Co 10.29 actual - 3.75 Max FAIL!!!

@ Idle
Hc 593 Actual - 450 Max Fail!!!
CO 1.46 Actual - 5.00 Max Pass

so short of paying to dyno the car and tune it then throw alcohol thru it im stuck...

its a slant six with
.510 cam 246 dur @ .050
9.3:1 comp
heavily ported head
.080 overbore
600dp holley on clifford manifold
hooker super comp headers with (2) 2 1/2" collectors "y" into single 3"

i think it was running 67 or 68 primary jets
 
Weve been without emissions testing here since 2007,and now they are bringing it back.Before tests,I use to change the oil,plugs,pcv valve,air filter and drove it around or take it on the highway to really warm it up.Dont let the car idle before taking it,i mean really open it up on the highway or a country road for awhile.I would also try to find a shop with a exhaust analyzer and see if tweaking your carb well help.Your numbers are not too bad,but high HCs at idle versus low HCs at load.Combustion temps are lower at idle,which explains the higher HC readings since HCs are unburned fuel.Try looking into new plugs,plug wires,a cap and rotor,maybe check your float settings and leaning out the carb a bit.
 
the cam 246 @ .050...going to have problems getting it to pass
 
man oh man I love detroit my car is originally from cali so its hooked up with all that smog BS
 
Your carburetor is way, way too big for your engine. Even once you put an appropriately-sized carburetor on the engine and get it dialled in, even though your '68 is subject to very lax limits, you'll still be hard-pressed to pass emissions with that cam. It sounds like the build was not planned with real-world street driving in mind; you'll have to make some changes. The good news is once you've done so, the car will be much more drivable (and less costly to run) on the street.
 
slantsixdan said:
Your carburetor is way, way too big for your engine. Even once you put an appropriately-sized carburetor on the engine and get it dialled in, even though your '68 is subject to very lax limits, you'll still be hard-pressed to pass emissions with that cam. It sounds like the build was not planned with real-world street driving in mind; you'll have to make some changes. The good news is once you've done so, the car will be much more drivable (and less costly to run) on the street.
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we go thru this every time... so im not going to go there but i just moved to a different state where i have to smog it.
 
1BadDodge71 said:
Weve been without emissions testing here since 2007,and now they are bringing it back.Before tests,I use to change the oil,plugs,pcv valve,air filter and drove it around or take it on the highway to really warm it up.Dont let the car idle before taking it,i mean really open it up on the highway or a country road for awhile.I would also try to find a shop with a exhaust analyzer and see if tweaking your carb well help.Your numbers are not too bad,but high HCs at idle versus low HCs at load.Combustion temps are lower at idle,which explains the higher HC readings since HCs are unburned fuel.Try looking into new plugs,plug wires,a cap and rotor,maybe check your float settings and leaning out the carb a bit.
Click to expand...

all is new, the motor only has 6K on it. but i think some 5 gs time is in order
 
805moparkid said:
so being my day off i welded in my new cat and prove the piss out of it to get it smogged... cuz i have to here in az!!grr. so anyway it wasn't even close to passing
@ a loaded 30mph roll
HC 349 actual - 450 Max Pass
Co 10.29 actual - 3.75 Max FAIL!!!

@ Idle
Hc 593 Actual - 450 Max Fail!!!
CO 1.46 Actual - 5.00 Max Pass

so short of paying to dyno the car and tune it then throw alcohol thru it im stuck...

its a slant six with
.510 cam 246 dur @ .050
9.3:1 comp
heavily ported head
.080 overbore
600dp holley on clifford manifold
hooker super comp headers with (2) 2 1/2" collectors "y" into single 3"

i think it was running 67 or 68 primary jets
Click to expand...

Okay lets look at the readings one by one and what you can do to help it pass. Lets start with loaded. High CO (partially burnt fuel) means it is running on the rich side of things. Lean it out by putting a smaller jet in it. I would lean it out till it starts to get a little pop out the exhaust on cruise then move up a couple of sizes. DO NOT DRIVE IT FOR EXTENDED PERIODS THIS WAY it will probably damage a piston. If it misses under load your HCs will go through the roof.

Next Idle
The HCs are high which is unburnt fuel that the CAT isn't taking care of. The Cat is designed to be close to the header and can be too cool. Your COs are low which indicates its pretty lean. I bet the cam is what is causing the low speed miss which would drive the HCs through the roof. Since its a Slanty I guess its a solid lifter cam. I would loosen the lash to mellow out the cam. I cant tell you how much because it will be up to you and how big your sack is. I also would run the timing a little retarded that will cause the exhaust to run hotter and hopefully get the cat up to operating temp.

Once you get to the station ask the Mechanic if you can run it around the block and start the test immediately when you return. Then run it around the block in first or second with the RPMs up to heat the cat. I hope this helps. When I used to have to go through this in Ca when my turbo Dart was runnning I would put my stock 273 back in it for the test. It was about 4 hours worth of work but it worked every time and was really less stressful.
 
turbodart68 said:
Okay lets look at the readings one by one and what you can do to help it pass. Lets start with loaded. High CO (partially burnt fuel) means it is running on the rich side of things. Lean it out by putting a smaller jet in it. I would lean it out till it starts to get a little pop out the exhaust on cruise then move up a couple of sizes. DO NOT DRIVE IT FOR EXTENDED PERIODS THIS WAY it will probably damage a piston. If it misses under load your HCs will go through the roof.

Next Idle
The HCs are high which is unburnt fuel that the CAT isn't taking care of. The Cat is designed to be close to the header and can be too cool. Your COs are low which indicates its pretty lean. I bet the cam is what is causing the low speed miss which would drive the HCs through the roof. Since its a Slanty I guess its a solid lifter cam. I would loosen the lash to mellow out the cam. I cant tell you how much because it will be up to you and how big your sack is. I also would run the timing a little retarded that will cause the exhaust to run hotter and hopefully get the cat up to operating temp.

Once you get to the station ask the Mechanic if you can run it around the block and start the test immediately when you return. Then run it around the block in first or second with the RPMs up to heat the cat. I hope this helps. When I used to have to go through this in Ca when my turbo Dart was runnning I would put my stock 273 back in it for the test. It was about 4 hours worth of work but it worked every time and was really less stressful.
Click to expand...

thanks for breaking it down for me! and i was thinking of just a swap to a stock motor.
 
Get collectors car insurance, if you can. Pretty sure AZ has an exemption in the Smog laws, if you have collectors insurace on it no smog test necessary.....
 
inkjunkie said:
Get collectors car insurance, if you can. Pretty sure AZ has an exemption in the Smog laws, if you have collectors insurace on it no smog test necessary.....
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yea but its my daily driver... and dont they have milage limits?
 
Wow! You have to smog test a car that old in AZ. Boy I thought Mass was bad for that stuff but 84 and older is exempt from emmissions, 85-95 they put on the rollers and 96 and newer they just check for OBD diagnostic codes.
 
Change your cam to a smaller one re jet your carb leaner or replace with a smaller one and you should be good to go.
 
you would think,( or I would any way) that it would only have to meet the standards of the year of the car, ie. the old diesels are exempt from the new standards, so if they want to smog check a 1909 model it shouldn't have to meet 2010 standards, as if it could any way.
just my 2 cents.
 
805moparkid said:
yea but its my daily driver... and dont they have milage limits?
Click to expand...
Some do, some do not. But they all require having another vehicle as a dd.....AZ does offer a 1 year exemption, so at least you would not have to deal with it right now.....I had a truck that would not pass the idle test, took it to my nieghbors friends shop, that jacked around with it until it passed. Cost me $40, but it beat the hell out of going back several times. In the past I also registered a vehicle out of Maricopa County. Back then Prescott did not have emission laws. Was able to use a Mail Boxes Etc as my address as it was a physical address. MVD, form what I remember, will not register a vehicle to a PO box. Mail Boxes Etc has a regualr address, followed by a Box #, hopefully that made sense because I just confused myself.......
 
inkjunkie said:
Some do, some do not. But they all require having another vehicle as a dd.....AZ does offer a 1 year exemption, so at least you would not have to deal with it right now.....I had a truck that would not pass the idle test, took it to my nieghbors friends shop, that jacked around with it until it passed. Cost me $40, but it beat the hell out of going back several times. In the past I also registered a vehicle out of Maricopa County. Back then Prescott did not have emission laws. Was able to use a Mail Boxes Etc as my address as it was a physical address. MVD, form what I remember, will not register a vehicle to a PO box. Mail Boxes Etc has a regualr address, followed by a Box #, hopefully that made sense because I just confused myself.......
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haha i think i got u! i need a physical address, not a po box
 
Find a shop that takes tips. $50 cash should do it. :mrgreen: It has worked for me in the past.
 
Badart said:
Find a shop that takes tips. $50 cash should do it. :mrgreen: It has worked for me in the past.
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i would do 100 but here they are all state run, they wont even do a pre-test! they told me people got hurt?!?!
 
so passed with fly colors!

Loaded
HC 36
CO 00.00

Idle
HC 137
CO .49

so next yr im not going to quite go extreme on the smog tune haha
 
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