I just put a catalytic converter on my car. Went to get it inspected and I did incredibly worse than when I didn't have one. I'm trying to set my carburetor (Holley 4160) up so I'm not reading 1100 on CO2. I have smaller jets already. What would be a good suggestion about the power valve? I have no idea what those numbers mean. This is the first carburetor I've ever dealt with so I'm a complete rookie when it comes to it. I know the idle screw and (whatever they're called; probably something simple) the screws on the sides of the front bowl. I've gotten this car to pass before but for some reason, I bombed completely. I noticed when the inspection was being done, revving the engine made soot come out the back. It was minimal but I know it's running rich. I read the tuning carburetor thread and understood some of it.

 

i just got through inspession last week, first time was pretty bad second time they shut it off and then it wouldnt even idle so lean it was third time was a perfect run, i got 66 jets on the primaries, 12* advance cat converter borrowed from a Hemi truck, the idle at 1000 and as lean as possible new plugs and oil, i couldn't believe, no EGR no air pump nothing

 

That's awesome! I've got almost the same setup; no EGR or air pump either. Just a carb and a cat. I know it can be done, I just don't know where to go from what I've got. I have a 65 primary power valve but not sure how much to change it. I need to get a vacuum gauge and get a reading. I'm still in shock i read an 1100 on CO2...ridiculous.

 

power valve has nothing to do with it they only rev the engine to 2000rpm not enough to activate the power valve, its all in the idle circuit lean it as much as you can one 1/8 of a tourn at a time give it a few seconds an put the transmission in drive with the breaks on, if it doesn't stall with the load do it again untill it does then go back 1/8 and you're as lean as it can be, check for driveability also your plugs must be black now with all that CO2, clean them up or put new ones, use regulas gas not premium, thats what i did on mine

 

I'm sure you've misstated that.

What were all your numbers?

 

WITHOUT CAT
IDLE
HC ppm: 173 (standard 220)
CO%: 3.91 (standard 1.2)
CO2%: 11.9
O2%: .9

HIGH IDLE
HC ppm: 894 (standard 220)
CO%: 1.97 (standard 1.2)
CO2%: 12.6
O2%: 1.5

WITH CAT
IDLE
HC ppm: 267 (standard 220)
CO%: 7.37 (standard 1.2)
CO2%: 10.0
O2%: .5

HIGH IDLE
HC ppm: 1110 (standard 220)
CO%: 1.55 (standard 1.2)
CO2%: 14.1
O2%: .5

 

now that i looked at my report CO2 it's aroud 12, not in the thousands, HC ppm is the highest number and the standard is 220 in NJ

 

Much better... high CO2 is a good thing, but since it's expressed as percentage, it would be remarkable if it was 1100.

You're running obscenely rich, which isn't the cat's fault.

I'm surprised they even let you test with visible smoke. That's usually an automatic fail since it's very hard on the calibration of the test equipment.

 

wow do you have vacuum advance?

 

There was no smoke though. That was the kicker. The idle on the car is ridiculously high. I need to mess with it.

 

For numbers that bad, it's a fuelling issue, not a timing issue.

 

Haha if there were awards for emission failures, I'd have an acceptance speech. Vacuum advance?

 

Yeah that's what I gathered from it. HC is unburnt fuel. I need to check my plugs and lean the thing out.

 

It needs repair, not tuning.

 

What kind of repair?

 

Don't know, have to figure out why it's running rich to see what needs to be fixed.

 

Well...I ran a vacuum check anyway just to be safe and it turns out I need a different power valve. I had a steady 16" Hg. However, I did what you suggested and did the leaning out combined with putting the car in drive and got it as lean as possible. I need to pull a couple plugs to see how bad they are. Once my headers cool off I'll do that. I run regular as it is so that won't need to change.

 

Power valve won't be in effect at idle unless it's too large (unlikely) or blown.

Didn't you have a problem in your other thread, where the choke was sticking closed? Was it like that when you did the test?

 

I'm going to replace the power valve anyway; it's another thing in itself. I opened the choke completely (no restrictions) and it was fine. Also when I took the bowls off the carb, the fuel line that connects the 2 bowls was sitting weird in the gasket and restricting fuel delivery to the bowls. Whatever happened with that fixed the issue I was having. Still not sure exactly what it was but all is fine now. It didn't do it at inspection.

 

dont they do a visual on cars in NJ? how do you get away with a holley?

 

They recently changed procedure where cars '06 and newer get a 1 year extension or every 2 years. The first time I got it inspected after the swap, they opened the hood but only to use a sensor for something. They shut the hood and it was never an issue. That was the first time I've ever had my hood opened. I know the most serious thing they check in my car is emissions. They've never asked about it and as far as I know, it shouldn't ever be an issue.

 

they did open the hood on mine too to plug in the rpm sensor from the emmisions computer but they didn't say anything, they dont look for missing emissions parts or nothing, if you can pass the test without them that's because you dont need them and you can tell that mine has none of the factory smoog parts and has a open element air filter wich it was a no-no years ago

 

It's because the test doesn't reproduce the conditions which those components address.

 

The power valve won't be a factor for idle unless the throttle blades are open too far at idle. Since you said "The idle on the car is ridiculously high", then maybe that is the case.

The type of distributor and timing can affect these things. What type of distributor do you have? Where is the timing set? How was it set? If you can't answer these questions, then we can't really set you on the course to correct correct your problem.

As for smoke, you also said, "...revving the engine made soot come out the back". That's smoke. Most places would fail you for that regardless of what readings they got from the machine.