I went to inspection a few days ago. And of course with my luck i failed! The standard "HC" is 500. My result was 4250. Talk about astronomical. I have a zz4, with a HOTCAM, and 750 edelbrock carb. A 74 had no emissions equipment on it as far as i know. What can i do to possibly get it through??
Thanks in advance.
Chris


[Modified by 74VETTE, 12:54 AM 8/28/2001]

 

Adust timing, run lean and get better cats.

 

thanks Rhys,
Im gonna try to lean her out, but my initial timing is 10 degrees. What should i go to?? 6 or 8? 74 never had cats, thank god, but not in this case...lol
Thanks again....
any other opinions
Chris

 

If all else fails, take it to a shop that has an exhaust tester.
Have them tune the timing and mixture so that the exhaust sniffer will not fail you next time.

It may even run better.

 

74vette - What did you do to get by the previous inspections? Or is this type of smog inspection new to your area?
Whatever the answer is, you still need to get your car to pass inspection. First of all, how much time do you have before you need to re-test? Knowing this will allow you to do some research. Find out what the law requires for smog equipment.
I don't think they can make you add anything that didn't come from Chevrolet in 1974.
That HC number sounds high, but I don't think that cam has that much overlap.
Make sure the motor is fully warmed up before any testing (at least 30-40 minutes of highway driving). Also, if you are using Super to keep from pinging, you may want to switch to a low or med grade of gas for testing purposes. Premimum has more additives to bring up the octane, but it tends to be on the sooty /oily side. (at least it does in California)
Probably the best thing to do is what Bseery reccomends. Find a shop that has a gas analizer that will work with you. Make a note of all of your settings before you tweek anything.
Let us know what happens. :seeya

 

The best way is to pay the tester to time the engine until it passes, if he will do it. You will need to retard the timing allot. You should start at 0 degrees and will probably have to go to ATDC. You car will have no power but shoul pass the test. Bring a wrench so you can fix the timing around the corner.

 

Don't know what the law is in New Jersey... But here in California you must return your vehicle to it's original configuration. Engine, wires, hoses, smog pumps, catalytic converters... even the gas cap is checked.
The law is for all vehicles manufactured after 1973. It cost me more than 500 dollars to pull that off and 3 visits through the inspection before they signed me off. -Good Luck-

 

Chevron claims that all major car manufacturers use Chevon gas to pass emission tests. You might try it.

 

Having lived... and failed emissions in NJ....
The NJ inspection stations are not equipped and are not allowed to do any work on a car going through inspection. The people working there have no mechanical ability other than doing inspections by the book. I didn't know they checked the gas cap for the unleaded nozzle restrictor, and they flunked me because the gas cap was locked. I had to get back in line and wait another 1.5 hours just because the gas cap was locked and they were too lazy to ask me to open it. Can you say "OBNOXIOUS" ?? They didn't tell me until AFTER the failed sticker was on the car. So... don't expect any favors at those inspection stations. Next point... the equipment at those inspection stations is not maintained properly... I have driven my car through one station where it flunked, and then driven it to another one where it passed. I have, at times, leaned out the mixture, dropped the timing back, and turned up the idle to pass, but if the idle is too high, they will nail you on that as well. I am currently having trouble with a Chevy Silverado 305 here in NC, and I looked into a 2 gas analyzer. The best deal I found was about $2800 (new). That would be nice to have, but not very cost effective. If you adjust your specs lean and still fail, you may have no choice but to take it to a shop with an analyzer and have them set it up for you. Also... make sure you have fresh oil in the pan... the vapors get burned via the PCV, and dirty oil vapors will reduce your chances of passing.

 

'74 did have AIR and PCV valve did it not? Other than that, I don't think it had anything. 4250 seems REALLY high though. Lean it out as much as you can and retard, retard , retard until it passes. It'll run like crap but once you get it past, you can re-tune it back to where you want it.

Some states (I know Pennsylvania used to, but not New Jersey) have inspections done at local shops, so those shops can tune it until it passes, but NJ has state inspection stations that will not work on your car.


[Modified by 79MakoL82, 9:45 AM 8/28/2001]

 

PCV: yes. EGR: yes. AIR: all but the federal L-48 automatic (mine! ). They also had TCS (transmission controlled spark) and/or thermo-override system, but these guys at inspection stations usually don't know/care about them.

-Pedro

 

I'm surprised that your car even runs. It's just got to be spewing black smoke. I used an Edl 750 on a 355 for about 10 years. A hot rodded car in proper tune and relatively new will make nearly it's most power and still pass a sniffer. It would fail because of visual and no cats, but the hydrocarbon and CO, CO2 levels of a dyno tuned motor will pass or be right on the edge of passing.

To get it to work I'll ask you a few questions what is your idle rpm and your inches of vacuum? What is the max rpm for idle testing and min & max for higher rpm sniffing - here it's 2200-2500 for 60 seconds? Max low is 1200 rpm.

What are your jet and rod sizes? what color vac. springs are you using? I will tell you the quickest way to tell if your jetting is way rich is to just pull the full vacuum line off the front of the carb. If you’re idle speeds up and smoothes out your way fat.

I will assume all the normal things. That you have all new, PVC, air cleaner, plugs, wires, cap, rotor, oil change, and motor is hot

 

Try adding some methanol (avail. at auto stores as gasline antifreeze), ethanol (pure drinking alcohol-avail. at liquor stores-a bit of a waste to burn in your car), or other oxidizing additive such as MTBE (avail. at auto parts stores). These additives add oxygen to the fuel to complete the combustion of the gasoline & in the right proportion should help without a converter & are added to reformulated gasoline in parts of the country requiring it. You'll have to play with the proportion to add--do this with only a little gas in the tank so you don't have to add too much.

 

As far as gas analyzers are concerned, get in the phone book and call some local "environmental" firms, the ones that specialize in storage tank removal, site assessments, etc. They have confined space gas analyzers that read hydrocarbons in the ppm range, and will probably sniff your car just for a ride around the block. Some of these meters are very accurate, and the cost new about $1500-4000, depending on the brand and amount of sensors. They usually read ppm (or % LEL), O2, CO2 and CO.

 

In NJ if I am correct you can also get your car inspected by a gas station. And if that is still the case you slip the guy a couple extra bucks and suddenly you have a legal car :cool: If they are still allowing the gas stations to do inspections pay the extra $$$ and you dont need to do anything to your car.

 

I've been thinking about picking up a used gas analizer myself.
I worked in a garage a few years ago & they had an old one in the back they never used - probably about 25 years old. I asked them about it & at the time they didn't want to give it up.
Try a local college with an auto shop course. When I was going to their tune up class, I would use the analizer several times a week. - it's a great tool for tuning :yesnod: (you may need to sign up for class to get access to their equipment.)

 

Chris -
A few thoughts on your dilemma....

Hydrocarbons are primarily an indication of ignition problems. Generally, hydrocarbons will go down when timing is retarded. Hydrocarbons go up with bad spark plugs, bad plug wires, misfire, or advanced timing.

How was your CO level? Generally, Hydrocarbons and CO will go opposite as you make adjustments. In other words, if you CO was low, you can richen the carb up just a tad to increase CO, and this will bring HC down.

Did you get a reading on the HC at elevated rpm? Generally, as rpm goes up, HC goes down.

So here is what I would do if I were you:

Change plugs. Make sure your vacuum advance unit is not hooked up to direct manifold vacuum (thereby pulling in a bunch of timing at idle). Drop your timing back to about 8 degrees.

Find out what the upper rpm limit is for the test at idle. It's usually about 1200 rpm-or-so. Get your idle rpm right up against the limit without exceeding it (give yourself just a tad of margin so you don't fail the test for excessive rpm).

If you were okay on CO, turn your idle mixture screws out (richer) about 1/4 turn.

If this still fails, you have some tuning and tweaking to do. There are quite a few independent shops around that have old emissions testing machines that they use for tuning purposes (I even have one in my garage). Emmissions testing places are usually prohibited by law to allow you to tune the car on their machines, so you can give up on that approach. But you should be able to find an independent shop that will put your car on their machine and tweak some of your variables while producing a real-time display of the results. I used a couple of shops in the Denver area for this purpose before I bought my own machine, so I'm sure there are places in your area that can do the same. I used to offer the shop owner anywhere from $20 - $50 just to plug his machine into my car and allow me to "play" with the adjustments a little.

Good luck with the tuning. Let me know if you need any assistance.

 

74VETTE
The answer to this problem is very simple.
Register your car as a historic vehicle, In NJ any car 25years or older qualifies and there is no more inspection.

Gary

 

Dosen't Historic Plate's have limitations on vehicle use?

 

Thanks everyone for some advise....
Here are the exact results of the test:
Tested at 900 RPMs, even tho my idle is at 750, they revved it till 900
HC: Standard = 500, Result = 4250
CO%: Standard 5%, Result = 2.15
I drove about 20 mins on the highway before i got there, but idled for maybe 15-20 mins.
Previous inspections i had a weak 190HP motor in there, but recently added whats listed in my signature. Im pretty sure the inspections have gotten much stricter around here anyway. I have about 40 days left before i MUST go back.
Here are a few question tho,
1. A few people are contradicting each other about rich and lean. One guy said to lean it out, and another said to richen it to raise the CO%, but lower the HC. Which will send me in the right direction??
2. What if i were to use regular gas, but throw in some kind of additive like 75 Hot One suggested? Is there truth in a lower octane will help?
3. We seem to all agree to retard the timing down a lot...is it unsafe to do this as low as even ATDC??

Historic would be great, but you need 10 years of driving expereience, and with me being only 20 theres a problem.

I really appreciate everyones help, i sure hope i can get it to pass. Quite rediculous i have to go through all this trouble with a car older than 25 years old.
Thanks again,
Chris