passing emissions?

SteveMelchiorre

SteveMelchiorre

Well-known member
Here in British Columbia all cars need to pass "Air Care"
I took in my 69' Mustang - Stock 250, Carter RBS, Stock Dizzy.....and I almost passed (or if you prefer - I failed)

I passed the Idle test for HC and CO easily.

..and I passed the NOx in the Driving test but failed the:
HC - allowable 294 - reading 378
CO - allowable 3.09 - reading 8.83

I've been doing a bit of hunting around this site and other and it seems that in order to bring these numbers down I need to retard the timing a bit. I'm currently running at 15 degrees.

Is this correct?
Steve....

--and I recently changed the oil and checked spark plugs #2 and #6 they were both a light tan.
 
Change your car's oil before scheduling an emissions test. ( you did that)
Fill your tank with premium gasoline. ? it burns cleaner
Drive at least 20 miles before having the vehicle tested

Tips for Reducing HC during Emissions-Testing
http://www.426-hemi.com/auto/emiss/testing/tips/#HC


Tips for Reducing CO during Emissions-Testing
http://www.426-hemi.com/auto/emiss/testing/tips/#CO

alot of good info below
http://www.426-hemi.com/auto/emiss/testing/tips/
http://www.aa1car.com/library/2000/ic60032.htm
 
I knew a guy that would retard the timing to around 0* BTDC to pass emissions on his big full size truck. Try knocking it down a bit more from 15* and it may help.
 
I've tried to pass Air Care 3 times now. Each time I get closer but I'm still failing the Driving test for
HC - allowable 294 - reading 332
CO - allowable 3.09 - reading 6.53

Oil is new, Spark plugs all have a nice tan colour, Timing is at 6 degrees, Vacuum holds at 20 nicely, Idle RPM is about 650 in Drive..... the only thing I have yet to dig into is the distributor and check the points.

So my questions are:

--Do I try setting the timing to 0 and increase the idle RPM up to 1000 or so as Mr Hemi suggests?
--Take it to a local garage and have them tune it up to pass?
--Check and change the points in the distributor (I've never done this)
--Purchase a DUI or DSII ignition -- I am planning on doing this -- just wasn't planning on it right now.

Thoughts?
Steve....
 
SteveMelchiorre":1f2m0ipj said:
Check and change the points in the distributor (I've never done this)
Click to expand...

That's certainly worthwhile IMO. I'd also make sure the pcv system is maintenanced/operating properly, and use a heavy weight oil, straight 30w.

Both HC & CO being high would seem to indicate running rich, but your plugs don't seem to indicate that :hmmm:
Radical solution (probably frowned upon): plumb a catylitic converter in place temporarily for the test, then remove it afterwards and save it for next time :twisted: Ignition tune-up & pvc definitely worth attending to...too much blowby would run your numbers up me thinks.
Good luck!
 
not to familure with your emissions,,on my set up I cut a notch in the hose that goes from the bowl vent to the canister,,so it sucks more "clean"air in.... it flys thru emissons,,,,bottom line though is that something is wrong and needs to be fixed
 
He's ok on NoX and high on HC and CO, that means it's probably ok to run hotter; I would try a 205º thermostat and some heavily oxygenated fuel (add some gas dryer if necessary). Make sure it is thoroughly warmed up.

And yes, do the points. Side gapped plugs won't hurt a thing either.
Joe
 
Also, try to retard the timing a little more, even if you do it in the parking lot outside the emissions test and reset it after. Used to have to do it on a friends big K1500 chevy. We retarded the hell out of the ignition to get it to pass.
 
I'll check my points later tonight after work and reply back with what they look like.

I'll also check what kind of plugs are in my Mustang right now.... perhaps they're too cold.

The air filter only has about 1000 miles on it. I might just take it out for the test and see if that helps.

Re: side gapping - I'm definitely going to try that as well.

Thanks for all the advice.

Steve...
 
Ok... so a few more observations / questions....

I'm running Autolite 46 spark plugs <-- Is this a good plug for a 250?

Under the cap all looked relatively clean but I couldn't help but notice that the rotor had about 1/4" of free play in it when turned by hand. Is this normal?

The breaker points are aligned and appear a bit worn but not what I would call excessive. I was reading in my shop manual on how to set the gap but honestly it seems a bit confusing. I'll go over it again in the morning and see if it makes more sense.

Steve....
 
Just a thought and it can pass just as quickly, but have you thought about installing a Pertronix? It idles more efficiently and burns the fuel more completely during operation. You can retard the timing and clamp down on the idle mix, leaning it out significantly.
 
There is supposed to be a spring clip on the rotor shaft to hold the rotor fairly firmly. With age they either break or get lost. They seem to be one of those parts that never existed. I have used several wraps of teflon thread tape to keep em snug.

If the points are not in good condition and properly gaped you will get an inconstant weak spark. They are cheap enough and new points can be set fairly accurately by the gap method. Its best to confirm them with a dwell meter. With a dwell meter you can also get an idea what sort of shape the bushings are in. When the bushings wear the distributor shaft floats around based on rpm and changes the dwell.
 
The air filter only has about 1000 miles on it. I might just take it out for the test and see if that helps....
Click to expand...

Don't run it without the air filter :shock: it needs to be tuned with the air cleaner on with a filter and the hot air pipe hooked up too! :hmmm:
 
bubba22349":1cz1c6j1 said:
The air filter only has about 1000 miles on it. I might just take it out for the test and see if that helps....
Click to expand...

Don't run it without the air filter :shock: it needs to be tuned with the air cleaner on with a filter and the hot air pipe hooked up too! :hmmm:
Click to expand...
Agreed you don't want to run very long without an air filter, but in a desperate attempt to pass an emissions test it just "might" help to lean it out that tiny fraction by which it is currently failing, also cooler air would be more dense and perhaps help a bit as well.
I'm just guessing though :hmmm:
Joe
 
Thanks for all the thoughts.

I'll keep the air filter in.

Regarding the Pertronix, that's the one upgrade I'm on the cusp of right now but I don't want to throw good money after bad -- Meaning that I am going to upgrade to a DUI or DSII and don't want to "waste" the cash.

Could/would changing over to an electronic ignition make the difference I'm looking for?

Steve...
 
My opinion is that it would help some :hmmm: though you should be able to do it without as Joe said lean it out. Also as was said reduce inisal timing setting. In Ca. we used to have a system that was mandated to be installed on the older cars (pre 1966) it was called a no nox kit :roll: before that was to also install an aftermarket PVC system. :mrgreen: (a good thing) Basically with the no nox kit timing was set to 0, vac advance capped off, and carb leaned out, also came with a decal warning not to drive at higher speeds. :shock: Performance suffered so of corse after passing smog test would set back again :nod:
 
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