Suggestions to help me pass emissions test

[rockytopmark]

I was sent the Illinois card showing my 1970 GT requires an emissions test. I can't imagine it will pass, but I'd like to ask everyone for any tips on what I can do to increase my chances.

Should I test with car cold or warmed up?

High octane fuel or lower octane?

Fresh oil or oil with some miles on it?

Hot day or cooler day?

Other suggestions?

I used a product once in a 1987 Mazda called Motor Medic that got me a pass after 1 failed test. Any other good oil additives that may help?

Thanks in advance...

[hrcollinsjr]

Simple things I used to have to do to pass before they started doing visual inspections and I just couldn't bring myself to weld on dummy cats on a vehicle with headers and duals.

Tune engine
Set timing at zero initial advance
Plug vacuum line going to valve cover and remove larger hose to valve cover so that it isn't sucking fumes from engine.
I picked the cheapest octane booster I could find that contained alcohol and added it to an almost empty tank of gas. Drive just enough to mix the gas before going through testing. After passing hopefully, immediately go to the nearest gas station and dilute the fuel mixture as too much alcohol can cause problems.
You may also want to pull the air filter element just before being tested.

Harold

[baronbors]

I was sent the Illinois card showing my 1970 GT requires an emissions test. I can't imagine it will pass, but I'd like to ask everyone for any tips on what I can do to increase my chances.

Should I test with car cold or warmed up?

High octane fuel or lower octane?

Fresh oil or oil with some miles on it?

Hot day or cooler day?

Other suggestions?

I used a product once in a 1987 Mazda called Motor Medic that got me a pass after 1 failed test. Any other good oil additives that may help?

Thanks in advance...

Simple solution- move to Texas. No emission test on cars older than 25 years.

[rockytopmark]

Must be 40 years here... the State's emission testing web site says 1967 or older are exempt. I may have to re-tag as antique, but that would restrict my driving to weekends. Right now the GT is my daily driver... 25 MPG or better helps the wallet stay fat!

[GTJIM]

the State's emission testing web site says 1967 or older are exempt.

Buy a 1967 Kadett Rallye .. or re-VIN your GT as one ......

Surely a 1972 GT would only have to meet the emission requirements that were in force when it was made ?? Anything else would be a bit impossible.

[lewdawg]

Here in Utah, Autozone, Checkers and all the other parts stores sells this stuff called "gauranteed to pass". Now I don't live in the valley so I am not required emissions but have been told by several that this stuff works. Just follow the directions and you should be good to go. The other suggestions in previous posts would no doubt also be helpful.

[manta73wi]

In southeastern Wisconsin, cars with "collector" plates (more than 20 years old) only have to be tested when you register them the first time after purchase. My '73 Manta (wtih Solex carb) passed the first time through and I didn't do a thing to it. My '75 (fuel injected) did not pass the first time through. I replaced the air filter with a fresh one, adjusted the fuel/air ratio for the FI to burn leaner, and put in a bottle of isopropyl gas line anti-freeze, and then it passed after doing this. These were all suggestions from folks here on the site and locally, so thanks! Engine should be warm from what I've been told. I would also recommend keeping an air filer in place as here they do check around to see that controls/equiptment are present. Good luck!
-Jeff W.
'75 Manta
'73 Manta

[tekenaar]

Simple things to do so you won't have to mess with it again. Some questions first:

Is Weber re-jetted for your engine, i.e. not just "out of the box"? VERY IMPORTANT!!, especially on primary as this is where you operate ~75% of the time and where you'll be tested! If "out of the box" jetting, I guarantee it's rich! This is a "do once to get it right" process and, once done, shouldn't have to touch this again, so it's definItely to your benefit. Lots of threads on this subject!!

Is your choke adjusted properly for summer? In your climate it may be necessary to adjust for summer and winter separately. Choke is only on primary and should be completely open when engine is warm. If in doubt, adjust fully open for test! This will also help your overall gas mileage if kept adjusted properly.

Engine should be at normal operating temperature and preferably have test done on cool day.

[rockytopmark]

Is Weber re-jetted for your engine, i.e. not just "out of the box"? VERY IMPORTANT!!, especially on primary as this is where you operate ~75% of the time and where you'll be tested! If "out of the box" jetting, I guarantee it's rich! This is a "do once to get it right" process and, once done, shouldn't have to touch this again, so it's definItely to your benefit. Lots of threads on this subject!!

The Carb is in need of a rebuild, so I was planning on doing that and re-jetting in the off-season, as I don't plan on driving this car after November. I'd guess it is out-of-the-box at this point. The re-jetting might also help solve the seemingly sluggish response during acceleration. With all the mods I have, I don't feel I am getting much more than normal power, IMO.

Is your choke adjusted properly for summer? In your climate it may be necessary to adjust for summer and winter separately. Choke is only on primary and should be completely open when engine is warm. If in doubt, adjust fully open for test! This will also help your overall gas mileage if kept adjusted properly.

The Choke is water variety and doesnt work. Rebuild will also include replacement with Electric choke. I believe it is always wide open while underway, so I think I am fine there.

Plug vacuum line going to valve cover and remove larger hose to valve cover so that it isn't sucking fumes from engine.

Makes sense to pull and plug the smaller line, but wouldn't leaving the larger line connected at least force some clean air in?

I am not very knowledgable about carb adjustments, but I have read various posts about setting the idle and mix and whatnot. I assume there is a way to lean the mix without re-jetting, so I will do that. I will test with car warm and try to make it a cooler day.

Would putting the Stock Air Cleaner stuff on instead of the Weber air cleaner (just open on top of carb) help pass the test? I have all of the parts and the adaptor as well... just hadn't gotten to it yet. Would I leave the filter in or take it out?

The for all the ideas, everyone.

[tekenaar]

The Carb is in need of a rebuild, so I was planning on doing that and re-jetting in the off-season, as I don't plan on driving this car after November. I'd guess it is out-of-the-box at this point. The re-jetting might also help solve the seemingly sluggish response during acceleration. With all the mods I have, I don't feel I am getting much more than normal power, IMO.

The Choke is water variety and doesn't work. Rebuild will also include replacement with Electric choke. I believe it is always wide open while underway, so I think I am fine there.

Makes sense . . . ?

I am not very knowledgable about carb adjustments, but I . . . will test with car warm and try to make it a cooler day.

. . . ?

Thanks? for all the ideas, everyone.

Doesn't work or just "adjusted" to be open all the time? Though this inside choke pic is a Solex choke, looks and works same on Weber. Electric choke differs only in method of heating bimetalic choke spring. Choke housing mounting screws are loosened to adjust choke by rotating housing . . . same on Solex and Weber.

[RallyBob]

Run the lowest octane fuel you can find, and one or two bottles of 'dry gas' additive (achohol).
Run the ignition timing 'straight up' at zero degrees, do not advance it.
Set the idle mixture screw until you achieve the highest possible vacuum reading, and at the lowest smooth idle speed you can attain.
Make sure you run through the test with the vehicle fully warmed up, and make sure the choke is OFF.
About 10 minutes before you go through the test....drive your car semi-hard. That is, keep the rpms up, and put a load on it while driving to the testing station. Just trying to keep everything 'clean' before they test the car. Fresh plugs help too. When you're done testing, go fill the tank with some high octane fuel to dilute the alchohol.

The emissions standards for 1970 are ridiculous...something like 6% CO and 750 ppm HC. If you can't pass this test, something is wrong! You should be able to get a stock Opel to idle smoothly at 1.75-2% CO.

If all else fails, I once ran an Opel through smog with a cheap ($59)aftermarket catalytic converter. This was in 1998. It passed 1998 standards!

Bob

[hrcollinsjr]

Makes sense to pull and plug the smaller line, but wouldn't leaving the larger line connected at least force some clean air in?

Would putting the Stock Air Cleaner stuff on instead of the Weber air cleaner (just open on top of carb) help pass the test? I have all of the parts and the adaptor as well... just hadn't gotten to it yet. Would I leave the filter in or take it out?

The larger hose pulls in crankcase fumes. Before emissions the valve cover was vented to the atmosphere. Air filter removed lessens resistance and hopefully increases air flow to the engine leaning it out.

Harold

[calvin]

In mo it is 7hc and I think it is the same for you folks over the river in IL.

If you change the oil and put a brand new front to back exhaust sytem even a 2.4 with dual webers and 1.50 out and 1.72 in valves will make it under 7 hc. having the clean pipe helps.

[Geek]

My wifes uncle used to say "make 'em run like your old girlfriends - Hot, lean and retarded". In other words, what Bob said.

[deaner]

My wifes uncle used to say "make 'em run like your old girlfriends - Hot, lean and retarded". In other words, what Bob said.

That was great!!! Thanks for the afternoon laugh.