Emissions problem here...

[xtreme80]

I know I know, most of you country boys out there don't have to bother with emissions, or any of that crap. Unfortunately, in the big city, I have to deal with it. It sucks, but that's life.

Anyways, here's my problem.. I need help figuring out why I'm failing. 1980 C10 350/edelbrock 600cfm carb. New engine, carb, manifold, fuel system, and ignition system. All OEM parts.

First, if anyone could get me a vacuum routing diagram for the evap system, I'd appreciate it. I think there's one floating around here somewhere, and I'll look for it, but if you got it handy, post it up.

Second, I'm failing on Hydrocarbons and Carbon Monoxide at Idle. Standard idle for HC's is 220 PPM, and I'm at 423. Standard for CO is 1.20%, and I'm at 2.34%. Kinda high. Both of those pass with flying colors on a loaded runout, but at idle it's ****.

I've already leaned the idle mixture alot, to the point where it was running like crap just to get it leaned out. But I really don't know what else to try other than dumping the happy juice in it.

If nobody has any suggestions I guess I'll have to buy some denatured alcohol. Anyone know where I can get that stuff?

Thanks for any help or advice.

[78chev]

Denatured alcohol can be bought by the gallon at any paint store ie. Sherwin williams, Dunn Edwards.

[Yankeelights]

How hot of a cam are you running?

[xtreme80]

Here's the specs on the engine. It says it's a 222 degree duration, but doesnt specify lift.

Specifications:
# Horsepower: 290 HP @ 5,100 RPM
# Torque: 326 FT/LBS @ 3,750 RPM
# Max. Rec. RPM: 5,100 RPM
# Compression Ratio: 8.50:1
# Heads: Cast Iron, 76 cc
# Camshaft Lift: Flat Tappet Duration @ 0.050'': 222° I, 222°
# Lifters: Flat Tappet
# Connecting Rod:
# Powdered Metal
# Block: 4 Bolt Main
# Pistons & Pins: Aluminum
# Crankshaft: Cast Iron Nodular, 3.480'' Stroke
# Rocker Arm: 1.5
# Ignition Timing: 34° BTDC total advance.
# Fuel: 87 Octane

Edit: Here's the quote for the lift.

The camshaft has .450'' intake and .460'' exhaust lift with hydraulic flat tappets.

[Yankeelights]

Wow, I completely missed the specs on your signature. Guess I was pretty tired lat night. Anyways, I'm puzzled because that's not a bad cam for emissions. At this point I'd be taking shots in the dark.

Autozone's web site has the diagrams that you're looking for.

~ Dave

[68GMC454]

hope you get it figured out..i dont have to deal with emmisions, thank god...i dont understand how it passes when reved up, and not pass at idle....good luck

[xtreme80]

Originally Posted by 68GMC454

hope you get it figured out..i dont have to deal with emmisions, thank god...i dont understand how it passes when reved up, and not pass at idle....good luck

The fuel being delivered to the engine at idle is using a different circuit. The idle circuit. If an engine passes on a load, but fails at idle, this means that it "should" be as simple as carb and timing adjustments.

[xtreme80]

Done. I passed.

On the way back from emissions testing though, the truck started heating up REALLY bad. It's never done that before.

Could this be because the timing was retarded alot, it was leaned out alot, and the gallon of denatured alcohol I dumped into the gas tank?

I havent had time to mess with it yet. I'm still letting it cool down.

[Eyegore]

I only added a pint of alcohol to my tank when I go through, and yes the timing could have an effect espically when its a 112 degrees and they constantly started and shut-off the engine during testing. Glad to hear it passed.

[Yankeelights]

Glad you passed. Thankfully in my part of Pa, the emissions components don't have to work; they just have to be there.

[xtreme80]

Technically they don't actually "test" the evap canister to see if it works, or the egr for that matter. I know my EGR probably doesnt work, but if they don't work, it's usually harder to pass. As long as it looks hooked up, I'm fine.

[Yankeelights]

They don't even test us here in the hills. They just look to see if the stuff is there and hooked up. I don't see the point, but I'm not complaining.

I wonder what the alcohol does to make things pass.

~ Dave

[raiders3581]

scuse me . what does the denatured alcohol do , new one one me.

[xtreme80]

I tried doing a quick google search on it to see if I could find anything that explained it better but Im not seeing anything.

Basically it drops your hydrocarbons and carbon monoxide down significantly and makes the engine burn alot cleaner. I can't explain why, but I know that's what it does...

At least it worked for me.