85 GT fails Emissions AGAIN!

[sscherin]

Well this time I thought I had it.. I hardly made a dent..

Fails with 81gpm CO and 7.9 GPM HC

Thats only 5gpm better on CO and 1gpm better on HC than last time.

What did I do to get readysince the last test?

replaced the Acell super coil with a new stock type
set timing to 10deg
replaced the 160 tstat with a 192
leaned out the carb again with .092main /.086 secondary jets .071x.047 rods
4hg springs (Edelbrock #1406 performer carb)

replaced fuel filter.
striped down the carb and cleaned it inside and out

re-routed all the vacuum lines to the correct locations (almost nothing was hooked up including the diverter valves for the air pump)
1/4 tank of 93 octane with a bottle of heat in it.

I'm thinking of really making a big jump leaner by trying a .086 jet on the primaries.

Some time soon I'll have to face the fact that the cats are probably toast.

One good thing.. they did it for free even though I was 16 days past the last test.

[Marz]

You can have an exhaust guy you trust look at the cats to see if they're still good.

The Coil and the T-stat shouldn't matter.

I know that here in Cali that carb would make it fail... just be the visual. Who know's how it'd do emissions wise.

What are the Co. smog guide lines/rules?

[85 Notchback]

I'm so glad I don't have to worry about emissions.

[sscherin]

It's passing visual just fine..

They dodn't even notice that teh whole EGR system is missing
It has a Weiand Stealth Intake on it.

If it fails with new cats I'm going to find a stock intake & carb or maybe just burn the car in a fit of anger.

[Zap's 85 GT]

Hmm. I passed even with a B-303 cam. I have no EGR system either. I routed tha vacuum lines to the air diverters to give the exhaust full time air. Leaned the snot out of the carb until it was running like crap. I also added a bottle of the "garenteed to pass emissions" stuff from NAPA.

[GT350R]

1/4 tank of 93 octane with a bottle of heat in it.

Still dont believe me about the lower octane gas?

[noslofiveoh]

i don't know if it's tru...just what i heard is it'll help make the numbers look better if u have a vacuum leak..like say pull the egr tube off the carb before pulling into the emissions place....would this help? or did i ingest worthless info? also, the lower octane gasoline makes sense to me...it burns hotter(faster) maybe theres still residue of unburnt fuel running thru the xhaust system setting off the emission machine...although i've never done testing tho, we don't have those tests here...as long as theres no smoke of anykind in the xhaust...ur good to go lol

[sscherin]

The first time I tested I had a tank of 85 octane..
This time with 93..

diffrenece?? not much.

[roller4v]

I really don't think your gonna get that car to pass with all the emissios stuff off of it. I could be wrong but I don't think so.

what you want to shoot for is a perfect 14.7 to 1 A/F ratio. If you run richer than that the HC will increase if you run leaner the CO2 will exponentially increase.

You can knock the CO2 way down by dumping a gallon of Isopropyl Alchohol in the fuel tank with 5 gallons of unleaded. Don't know if you can nock it down low enough.

The EGR is probabably going to need to be hooked up to get the HC low enough to pass.

Make sure you drive the car a long distance before you get it tested. You need to get the Cats good and hot. they'll work better that way.

Once again a LEAN A/F mixture is not nessesarily a clean mixture. Good Luck.

Oh.. one more thing. Clean oil will actually cut down on the emissions slightly.

[Southern_Pride]

Man am i glad we dont have emission. maybe if you cleaned the carbon out of the engine? I know nothing of emission. Just dump a little bit of water down the carb and listen real close. Do it very slowly. If ya got efi just take the aircleaner off and stick a glass next to the throttle body and open it up. Itll suck the water out of the glass.

[Boss 429]

You wont pass with that carb jetted that large! Why such large jets? A mega powerful engine? you should be much leaner than that, What is your Elevation? Can you borrow a 600 CFM Holley? They have "64" jets in them stock.It will be fine for the "part thottle" Dyno sniffer test. You are shooting your self in the foot with that Carb setup. Trying to help you. Gregg/Ohio

[sscherin]

Well an Edelbrock Performer carb isn't an Holley.. It's an AFB.. comparing jet sizes does no good because they work completly diffrent.

On an AFB you have a rod that sticks through the jet to resrict fuel flow.

These rods are steped so you have a cruse section of the rod and a power section.. the movemnet of the rod is controled through changeable springs..

this whole convoluted power/cruse system serves the same function as the power valve in a holley carb.

The advantage is you can tune the fuel enrichment and a backfire won't kill it.

Honestly I'd rather have the stock holley carb, egr and intake but I have to deal with what came on the car when I got it.

[Whtstang]

Just because your emissions systems are hooked up doesn't mean they are working right. Tailpipe HC & CO emissions are controlled by the Thermactor(smog pump), cats, PCV & heated air intake system. Mostly the cats & Thermactor which work together. A failure in either of these systems can push your emissions over the max allowed. Of course, they will never override an overly rich A/F ratio which will also eventually mess up the cats.

[Marz]

Just because your emissions systems are hooked up doesn't mean they are working right. Tailpipe HC & CO emissions are controlled by the Thermactor(smog pump), cats, PCV & heated air intake system. Mostly the cats & Thermactor which work together. A failure in either of these systems can push your emissions over the max allowed. Of course, they will never override an overly rich A/F ratio which will also eventually mess up the cats.

Don't forget that the EGR palys a major role in that too.

If the EGR isn't working it wont pass either. And... with that stealth intake on there... that EGR isn't working.

[Whtstang]

EGR mainly controls NOx emissions. I didn't say much about it because NOx was not mentioned in the original post.

[lt_dan]

When my '85 failed with over 4500 ppm unburned HC, I found an EGR line under the carb heat plate that had burned thru. Replaced it and it passed fine. Also, my needle and seat in the stock carb would wear out every few years. Raw gas would come out the tailpipe and the giant single cat would glow red from the gas burning in it. Replaced the needle and seat for about $28 (carb kit) and that would fix it. That happened twice.

Since my conversion fo Mass air EFI, I no longer worry about it. Smooth idle at 500 rpm and cold starts every morning, not that it gets very cold here in FL.

Dan
'85 red GT T-Tops, too many mods to list.

[Whtstang]

When my '85 failed with over 4500 ppm unburned HC, I found an EGR line under the carb heat plate that had burned thru. Replaced it and it passed fine. Also, my needle and seat in the stock carb would wear out every few years. Raw gas would come out the tailpipe and the giant single cat would glow red from the gas burning in it. Replaced the needle and seat for about $28 (carb kit) and that would fix it. That happened twice.
Dan
'85 red GT T-Tops, too many mods to list.

That's Interesting. I passed my '05 smog test with my EGR valve vacuum line disconnected & plugged because of driveability problems I get with it hooked up. Even though my NOx emissions were a little high{786ppm)they were still under the max allowed(1258ppm). My HC's on the other hand, were down on the low end of the scale at 28ppm with 174 allowed. I figured this was probably because of engine wear, the plugs I had in it at the time & a couple of degrees of timing advance. When I first tested in 1999(when the car was completely stock), HC was only 9. Unfortunatly, they were not checking for NOx emissions at that time, & I didn't get any NOx numbers for comparison.

As for as an out & out vacuum leak, well, thats another story.