Off the charts HC - California Smog Fail (1 Viewer)

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CruiserStuff

CruiserStuff

Joined
Oct 9, 2008
Threads
97
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Location
Lake Arrowhead, CA (was), Rocky Top, TN (is)
Hey Guys and Gals -

My 40 has been badly neglected over the last couple years and now I find myself having to pass smog in order to register it in Kalifornia.

To start, I have a '76 with a '79 engine. It is set up with the dizzy/igniter from the '76 (vacuum retard) and just about all of the stock smog goodies intact.

Before taking it for the smog test, I changed the oil (10-40) and filter (Napa Gold 1773), replaced the spark plugs (NGK BPR5EY-11) and plug wires, put in a new air filter and dumped a quart of denatured alcohol into a tank full of premium gas.

The old plugs don't look awful, but may have some evidence of burned oil on them. I get some smoke out the tailpipe at times, too, when it sits for a while.

Anyway, at the test I maxed out the machine on HC....over 2000! :doh::crybaby: The CO was at 3.19 (which should be around 1.80). :bang:

I came home and adjusted the valves (which hadn't been done in a LONG time) and took it back. Still no good. Came back home and did the following:

1) Checked that the smog pump is working
2) Did the lean-drop method of idle adjustment on the carb
3) Verified that the idle solenoid was "clicking" when key turned (though weakly, it seemed)
4) Checked vacuum at the intake (brake booster hose). Had 24" with a bit of a flicker (I'm at about 4000' elevation)
5) Checked the dizzy alignment. Don't have a timing light (yet) so just adjusted by ear.

I'll take it back tomorrow to see if I've made any headway, but I'm thinking with super high HC like this, I'm probably looking at burned valves or.....

Depending on what happens tomorrow, I'll do a compression check and start from there.

Any other tips, advice or opinions out there? Thanks in advance....
 
Evey two years when I have to do smog it takes me a weekend worth of work to install my cats back I use dropouts most of the time..

I change the carb back to stock put timing back to 2 degrees add all the pollution gear back them drive it for 30 minutes on the freeway to get hot, it squeaks by every year so far..
 
So, I'm not an expert on the earlier systems, but you might want to check if your air injection system is working. Also did your model come with a cat? That may be bad now. I guess I'm ignorant, 24" of what? What is that in PSI? How are the rest of your vacuum hoses?
 
It passed last time it was required....it wasn't pretty, but still made it through.

Since then, though, I've replaced the head and the head gasket. I should have been better about valve adjustments since then.

I'm pre-cat, but may need them to push this rig through. Hopefully there's a better/cheaper option...

24" of mercury (Hg) for vacuum reading...
 
Look for something causing a rich air fuel mixture.
 
CruiserStuff said:
Something like what exactly? Any ideas/thoughts?
Click to expand...

So, I mentioned it above, but your AI is pretty important to HC. You need to go through your entire emission system and try to ferret out the problem. Get a timing light and time it very well. I'm at 5.2k feet and I put my BB right at the edge of the window. Is your dizzy vac advance working? Have you tested it with a mighty vac? You set the timing with the vac port plugged.

Also, 24" of Hg is about 12 psi. Which isn't bad, but I know most rigs run more.
 
Get an emissions manual for your year from SOR and follow it to the letter. Do a wet and dry compression test to see what your compression is and whether the rings are OK. Is your choke adjusted properly? A sticky or improperly set choke vane can make your rig run rich. Set your timing with a timing light and make sure your plugs are new and gapped correctly. I keep a new stock paper air filter just for smog tests and afterward go back to my regular one. Your engine must breathe easily to get the CO down.

Good luck.
 
Your HC is stratospheric, while CO is close to passing, so it isn't running rich. It is either misfiring or it is blowing by a burned exhaust valve. It is unlikely to be an air injection problem because that system isn't designed to deal with HC concentrations that high. A compression test would be informative. Also: Is it flunking at idle or cruise RPM?
 
ColonelMustardFJ40 said:
An engine that is consuming oil can influence unburned HC. You mentioned oily plugs.
Click to expand...

Yes, that was my thought. Does your vacuum gauge bounce at idle or is it steady? Bouncing could indicate valve issues.
 
Thanks for the input from everyone. I took the truck back over to the smog station this morning and my CO was down to 1.0, so we're good there. The HC, however, remains unchanged and is still maxing out the machine at 2000...who knows how high it would go it the machine would go higher!

Chamba: The vacuum gauge flickers, but is not a bouncing wildly.

Pinhead: It is failing at idle. What would cause misfire and how would I diagnose that?

I have been noticing blue smoke from the tailpipe (especially when it sits at idle for a time and then I rev the engine) and the mechanic at the smog shop mentioned that he saw it, too, when I drove away yesterday. I'm thinking that I'm looking at (at least) some burned exhaust valves.....maybe in need of rings.

I'm gonna get a compression test done and will report back with some numbers. I'll also post pics of the spark plugs I took out to get your take.

Thanks again, guys, I really appreciate the help! If you have any other things to consider/check, please chime in.
 
I remember a rig... can recall who's... but it was good at CO and horable in HC... it was a bad valve at one of the cyls

its a PITA but maybe time for your head to be redone

had it ever been done before?
 
Fluckery vacuum needle may indicate a bad valve or simply the need to set them. A puff of blue smoke after idling for a bit is often valve seals.

Very easy to replace valve seals and you can set your valves then. This would be my first course of action if she were mine and I was unfortunate enough to live in California.
 
2 1/2 years ago is not a very long time... and build by mark i would say its fine machining wise... but as chamba said could be as easy as valve guide seals

i'd hate to see a bad valve on such a newly rebuild head... but... it does happen
 
To have that much HC is either misfiring or a bad valve. Misfire at idle is often from a lean mixture due to a manifold vacuum leak. If you can screw in the idle mixture screw all the way CW without stalling the truck and if you can see fuel dripping from the primary nozzle at idle, then these are signs of a manifold vacuum leak.

A bad exhaust valve would also do it as would low compression and blow by in the engine.
 
Pin_Head said:
To have that much HC is either misfiring or a bad valve. Misfire at idle is often from a lean mixture due to a manifold vacuum leak. If you can screw in the idle mixture screw all the way CW without stalling the truck and if you can see fuel dripping from the primary nozzle at idle, then these are signs of a manifold vacuum leak.

A bad exhaust valve would also do it as would low compression and blow by in the engine.
Click to expand...

I'm pretty sure I can stall the engine with the idle mixture valve screw, but will confirm today or tomorrow.

I've looked to see if I can see fuel in the primary nozzle at idle and have not seen it.....will double check though and report back.

Thanks Pinhead!
 
CruiserStuff said:
How would I determine if the valve guide seals are bad?
Click to expand...

With the smoking it's either head (too new of a rebuilt for that IMO) or rings or valve seals

Valve seals are easy for you IMO ... Use the rope method to keep the valve from dropping down ... This I have heard people use with great success

Also newer valve seals from what I remember are better than the older 2f style ... Can't recall the years to get ... Somebody here should know
 
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