ok i have a 91 firebird with a holley 600cfm carb the only thing on my car for emissions is the cat, the motor is not computer controled in any way... i have heard about leaning it out and turn down the timeing 4º and then add in the crap in your fuel.... but i need to know something will work.... i understade that its hard for a carb to pass emissions but i know it can be done.. i know for the later years its EZ for cards to pass but in 91 its very hard.

anyone have any idea's???? would jetting the carb help??

 

what you want to do is run the car real hot before you go to the emo station. take it for a ride up and down the high way or something, just get it hot. i used to run it for like 45-hour. and when you get to the station, dont turn the car off. let them do the whole safty test and everything with the car running if they do safty 1st... ive had 6 3rd gens and live in MA where emo is real strict. 5 of those cars had failed or no cats and i passed every time using that trick. the guy at the emo testing actually told me to do that before getting the sticker the 1st time. lol he knew it wasnt passing either

 

come on i know there has to be more tricks then that

 

I'll post back later this evening. Gotta run out the door right now. I've got some procedures that enable my 10.3 CR , 780Holley VS car to run cleaner than a 1991 FI car. My case is exceptional ( carb heavily modified ) but I do have a rather detailed list of things that definately help.

I'll see if I can sget my scanner up and running to scan my emissions test page.
L8R

 

Have another car run the test in its place.

 

just open up a small vacuum leak, like pull the plug off one of the small ports around the base of the carb, and lower the idle speed screw to compensate accordingly. Most states require an idle speed under 1000.

don't drive around like that. Pop the port open around the block from the sniffer. If you don;t pass, pop open 2 small leaks.

 

A good, clean carb(freshly rebuilt) with proper jetting(stock if your engine is stock), and a good idle circuit is a good start.

New cat(s) will knock emissions down as well, assuming the carb is good and your car is all tuned up. If you haven't taken care of your ignition stuff in a while (plugs, wires, cap and rotor) may as well change those.

 

did all that still failed

and that was with a 305... the new motor is going to be a 350 stock displacement it will have NGK plugs, MSD Wires 8.8mm , MSD 6AL box. i have a holley 600cfm carb that will be on the motor for the sniffer test and i'm going to jet it. the carb only has 3,000 miles on it. i think i'm going to put my timeing at 6º at idle this time last time it was at 8º i have a high flow magnaflow cat wityh only 3,000 miles on it. i'm going to put in a 195º t-stat in the car for testing but what else can i do? again this motor will be NON-Computer controled. again thie motor has to pass 1991 emission for the state of IL. i believe it has to be under 0.81

i still don't have the casting number for the new block and heads but i believe its going to be pre 86 becuase the dip stick is on the driver side.

 

I just passed here in GA on the dyno test, only emissions device on the car is a catco 3" cat that is a year or two old now. (setup is a 350 with Vortec heads, CompCams XE262 Cam, Performer RPM intake, 750 vac sec Holley, Edelbrock headers, etc) With it tuned like it runs well, it blew about double the limits on HC and CO. Limits were 144 HC and .92 CO% on the "25/25" test, mine blew around 250 and 1.92 respectively. Limits on the "50/15" test were 148 HC .83 CO, it blew around 200 HC and 1.75 CO or so.

All I did was lean the car way out to pass, lowered the float level way down to where you couldn't see what level it was at, put in the smallest jets I have (65s, usually running 69s), retarded the timing down to 4 degrees (from 8) and disconnected the vacuum advance, and turned the idle mixture screws in to the point where the engine started to stumble and left it like that. Like that the engine didn't run well, stumbled trying to gently pull away from a stop, idle was rough, etc. Obviously lean as hell. I turned off my fans and had the temp sitting around 225-230 degrees for the test, and it came in and blew 28 HC, .64 CO on the 25/25 test, and 13 HC .25 CO on the 50/15 passing with ease. (numbers very close to what my 305 TPI with all emissions except smog pump blew, my HC was actually lower significantly...)

Just did this today, very happy that I can tune this thing to pass and then go straight home and tune it back up to run right (and thus back to gross polluter status, lol). Screw the Eco-*****.... Unless your allowable levels are way lower than ours here I can't imagine you not passing. Oh, I forgot to mention they did test for NOX here, but mine was passing the first time around, and passed again with it all leaned out. Don't remember what the levels were before, but this time I only read 24 NOx ppm on the 25/25 test (allowable 1014, lol) and 36 on the 50/15 test (allowable 1110).

Good luck with yours. BTW here they do no visual check to make sure the EGR is there or anything (other than checking for a cat), so you may run into trouble there if they visually check for crap in your state.

 

jester, what exactly does that do to lower emissions? create a lean situation?

 

1) A brand new Cat works wonders. I have one that has flanges welded on. Only comes out once a year for Emissions testing. Otherwise I use a " Test pipe ". I do a lot of testing BTW

2) Gasoline with alcohol blend ( Ethonal ). Up in Canada we have Mohawk gas. 94+ octane with 10% Ethanol blend. The Ethanol really knocks down emmissions. 20 to 30 percent by some claims. It really does work. Lower grades usually has less alcohol added....so go with the Premium stuff. Lots of fuel companies in the states have Alcohol blends. Works a charm on carbed engines. ( FI too BTW...but not as noticable )

3) Fresh oil change and filter. Old oil will raise Hydrocarbon readings. Can make the difference between a Pass or Fail if you are close.

4) On older engines...pull the PCV valve out of the valve cover and tuck it away where it's getting clean air. Will really knock the Hydocarbon levels down if the engine is a bit tired and burns a bit of oil. Naturally only good if no underhood inspection is done.

5) Some of the " Pass Emmissions in a bottle " do work. CD-2 makes some good stuff. Not necessary with this car but I have used it in the past and it does work. Normally a crutch for some other problem though.

6) Enter a short line-up, directly after a good run. Or park the thing off to the side and run it up to 2,500+ for a few minutes with the hood up.. Get the Cat stinking hot....but the underhood cool. If you have to wait in a line for more than 10 minutes...abort the test. Fuel heating will play havoc with Hydrocarbon levels. Particularily noticable with open element air cleaners. Generally not a problem with Factory air cleaners and a Q-jet ( Factory calibrated to run stinking hot )...but a Holley and open element air cleaner are very sensitive for underhood temps. I always run with my cooling fan manually turned on. If coolant temp rises above 185 to 190 degrees, I abort the test.

That's the only " Tricks " that I use.

I find that when my car is running the " happiest " that's when it runs the cleanest. I run 14 deg of static advance, full manifold vacuum for distributor ( 15 deg in vacuum canister ), idle mix set to lean best ( 14.7 or lower...right down to 16 to 1 at idle ), idle speed at 1,000 RPM. With a good Catalytic convertor, timing retard is not needed. In my case it is detrimental to the emissions results.


Ignition must be in top notch shape. Wires, Cap, Rotor ...all must be 100%. A fresh set of plugs will usually help.

Brand new Air filter of course....and if you have a factory GM air cleaner ( LG4 cars ), replace the little Oil breather felt inside the air cleaner. An oil soaked felt will raise Hydocarbons.

Proper thermostat...180F should be fine.


-----------------------------------------------------------------------------------

355 CI, 10.34 to 1 CR, Holley 780VS ( Heavily modified...Annular boosters and Weber Power plate ), 218\228 @ .050 HR Cam 112LCA .500" lift, Hedman headers, Cowl induction hood with sealed AirBox for carb

 

BTW...here are the results from my test. Haven't got my scanner up and running, so I'll just have to print the results.

These are from our Provincial Emissions program called " AirCare"

Test consists of tailpipe check only. No underhood.

Gotta love that. They don't care what you have under the hood...as long as it passes the sniffer. Imagine...a Goverment program with common sense!!!

First they do a loaded driving test at 40KPH ( 25mph ) in 2nd gear ( Drive with autos ) to warm the Cat. About two minute test. Then an idle test.

1986 Camaro with 780VS Holley and 355 ci.

Driving test:

Maximum allowed.......Vehicle reading.......Average Pass Reading

HC (ppm) 206.00 .......6.00..........................36.50

CO ( %) 1.41.............0.00..........................0.13

NOx (ppm) 2072........370.00........................817.00


Idle Test:

HC (ppm) 339................44.............................101

CO (%) 3.91................0.00...........................0.44




Now that's pretty darned clean!!! Not a typo on the CO....all zeros'.

All I change from my day to day running is that I lean out the idle mix a tad...only about 1\2 to 3\4 turn in from best rich idle

 

ohhhh all they do there is just rev the motor in park???? here they put it on a damn dyno. that will go from 35mph and then go to WOT and don't let off till you hit 57mph

 

Unfortunatly they dont use the 25/25 or the 50/15 in illinois. We have the older version of the california test here. It a little harder to fool.

One thing i would suggest is changing from a 2 way to 3 way cat. They get rid of the nox too. That way you can lean your car way out and still pass the nox.

 

I you're referring to my post, no the test is done on a dyno ( Loaded test as mentioned ). They only need to go to 40kph ( 25mph ) because they test in 2nd gear which will give an engine rpm equivalent to highway cruise in top gear.

After about two minutes at steady cruise to check Highway emissions, they then put the car in neutral and let the car idle to establish idle emissions.

Cars built in 1992 and newer under go a much more rigorous test. This test takes about four minutes and uses a commute program with varying speeds and loads ( hills simulated by dyno ), coming to a full stop and acclerate to 50kph ( 30mph ) and includes both a freeway cruise mode ( 90kph or 55mph ) and on ramp acceleration mode. Very strict standards for 1992 and up.


For older cars 1982 thru 1991 they have slightly less stringent standards and these are adjusted year by year according to the model ( Fuel injection or EFI ) and total milage on the car. Cars with heavy miles get a bit of a break.


Here's a link to the site that you can look up the standards for your car. Compare an input for a 1986 vehicle to a 1991 vehicle for example.

Note for weight of vehicle use 1320kg. That is the registered weight of my 1986 Camaro. Use 5.0 liter engine displacement.

http://www.aircare.ca/inspinfo-standards.php


here's a link that shows all standards for all model years tested ( PDF format ):

http://www.aircare.ca/pdfs/AirCareStandards.pdf

 

go to the local farm supply store or a drug store and purchase 1 or 2 gallons of 99% pure isoproyl alcohol. mix this with the gas. you can put up to about 2 gallons with a nearly full tank. 1 gallon if you have half a tank should be fine. this stuff works awesome. it leans out the mixture and prevents it from detonating.

in Canada, it costs about 15 bucks a gallon. well worth it.

 

brad can you tell me how well that would work in an EFi with the injectors abd stuff?

 

It would help to know which part of the test you're failling? What are the numbers?
You can fail from too lean just as easy from too rich.

 

i would have to dig out the paper... but that paper is going to be useless as i'm putting in a new motor and i haven't had it tested yet

 

Pretty much a wasted post then.
If you don't know if or what you failed, then there's really no fix.

 

In illinois they only test two things. Hc's and Co's.

 

cerate a hidden vacuum leak, retard your timing, lean your carb.
have only a few gallons of gas in the tank and pour in a bunch of acohol.

 

Gumby-
About the vaccum leak-
What vaccum line should i disconnect on a TBI? The cruise control line? And will this mess with the ECMs scatter brain processing, sending codes or cause other problems?

Red HEET or yellow heet? red is methyl alch. yellow is iso alch.
Which is better in this situation and how much is too much?
I don't want to burn a valve or worse.

 

All of these are just for the test. You want a manifold vac leak so the car is sucking more air than the computer knows about. But it must be hidden and not loud so they can't track it down.

I guess iso as most people say just buy the 97%+ stuff at walmart. big *** bottle is 88 cents.

You may want to have just a gallon or two in the tank "watered" down with acohol and then soon as the test is over. Drive to the nearest gas station and fill your tank, while its filling pop the hood and un-do your vac leak.

You can also retard your timing a tad. Say your at 10 inital, go to 8. if your at 12 go to 10.

all of these are for the test only, should only be done right before the test and soon as it done, undo them.

 

Still puzzled as to which vaccum line to pull on the TBI unit that the comp. won't read. (therefore setting trouble codes)

 

yank the blub if it matters.

Just make a leak off the back of the manifold. There should be T fitting. Car will run a tad funky too.