Emission help!

[Txchevy18]

Ok guys Im looking for some ideas to get this thing passed.

Specs: 85 chevy 3/4ton 4x4, 40's", 9" lift, 4.10's till it passes( 5.13's are on order), 700r4 ,np208, sbc 350, shorty headers, holley truck avenger 670, holley red electric fuel pump, air pump removed, brand new high flow cats, 2.5" dual exhaust all the way back to glasspacks and turn downs.

First inspection try
High Speed
Standard Reading Result
HC(ppm): 220 92 pass
CO(%): 1.20 1.43 Fail
CO2(%) 13.7
O2(%) 0.2
Dilution >6.0 15.13 Pass

Low speed
Standard Reading Result
HC(ppm): 220 595 Fail
CO(%): 1.20 6.96 Fail
CO2(%) 9.9
O2(%) 0.5
Dilution >6.0 16.88 Pass

Timing was way off on this run, Starter would hangup but I gave it a try anyway. Fuel Pressure at 6psi, idle screws unadjusted from factory, Primary jet 68 , Secondary jet 89

Second try today
I played with the timing at work and now remember why i never set it, the previous owner never installed one. I just retarded it until the idle was at 650rpm's and it would start on one revolution of the starter. Fuel Pressure dropped to 3psi after a suggestion from a friends dad. Started tuning carb with vacuum gauge 16" before adjustment afterwards 19" , Changed primary jet to a 64, and put the 68 in as a secondary. Also removed electric choke. now pulling 20-21" of vacuum. Truck ran much better but was lacking being very responsive at high way speeds..

High speed
Standard Reading Result
HC(ppm): 220 34 pass
CO(%): 1.20 0.18 Pass
CO2(%) 14.6
O2(%) 0.0
Dilution >6.0 14.78 Pass

Low speed
Standard Reading Result
HC(ppm): 220 1376 Fail
CO(%): 1.20 3.96 Fail
CO2(%) 12.0
O2(%) 0.2
Dilution >6.0 15.96 Pass

I was driving back and it started dying as i was trying to take off. Bumped Fuel pressure up to 6 psi again, problem seemed to go away. I'm not sure what direction to go next. I talked to the mechanic there he suggested advancing the timing 4* and increase the fuel pressure back to 6 psi or more. He also asked about the charcoal canister and whether it was working. I know its there but i don't believe its hooked up. As soon as it passes I'm installing a 20 gallon fuel cell under it due to the leaking dual tanks.
Any ideas guys?

THANKS,
Txchevy

 

[rcamacho]

The Holley Truck Avenger carburetors are not intended for a smog legal application but they like most Holley carburetors can be made to serve. Here's a few suggestions:
Fuel Pressure: <= 5.5lbs in a street application. Should eliminate risk of blowing fuel past the inlet needles.
Choke: Ensure choke is fully dis-engaged when warm- both flapper and fast idle cam.
Idle mixture adjustment: Set warm, highest vacuum reading and then turn in 1/4-1/8 turn. Back out a bit if it starts to miss. This will give you the best lean idle. Set idle speed to spec.
Idle Fuel Restrictions: If the low speed test is running off idle - ~2000 RPM the air/fuel ratio is largely controlled by the idle fuel restrictions/transfer slot circuit. If it still does not pass you will likely have to lean out this circuit by inserting ~ 0.015in wires into the IFR's located in the primary metering block. If you're running a mild cam, this is a good idea anyway given the price of gas. Most of the IFR's I've seen in non-emissions carburetors run 0.033 to 0.035". Check out the forums on Innovate for some light reading if interested (http://www.innovatemotorsports.com/forums/index.php). I've recently taken 20% of the fuel out of my carburetor's idle circuit with no ill effects other than +mileage.
"The low speed jets are usually pressed in the block on either side of the power valve area. Little brass nubbins with a .030” to .040” hole in them. A strand of copper wire .018” to .024” can be found in telephone cable or a multi-strand 8 or 10 gauge. A piece 5/8” to ¾” long bent in a “V” so that one leg can go through the hole in the jet and the other leg into the adjoining passage into the main well to hold it in place is the deal. When the carburetor is assembled the wire can’t go anywhere. It’s just a little metering rod in a jet."
Timing: Make sure to check initial, total mechanical and vacuum advance. You'll want 32-36 degrees of total mechanical and 52 degrees w/ vacuum. If timing is off, emissions and power will likely be off as well.