NEED HELP PASSING ARIZONA EMISSIONS 1977 CHEVY K20 WITH REBUILT EDELBROCK

[oldeagle1]

Failing = Hydrocarbons(HC) Reading:   1st Idle Reading: 641, 1st Idle Standard: 350
                                                              Precondition Reading: 346, Precondition Standard: 300
                                                              Final Reading: 605

Does Pass Carbon Monoxide (CO):  First Idle Reading: 0.62, Idle Standard: 4.00
                                                        Precondition Reading: 0.87,  Precondition Standard: 3.00
                                                         Final Reading: 4.00
                                       
Helping my son (16) out with his "New Truck".  Has been to emissions 2 times, failed all 3 tests first round, 2nd time passed 2 out 3, getting better.  Has a v-8, 350, small block rebuilt Edelbrock crate engine with Edelbrock carb. with around 1,000 miles.  Adjusted the main screws in carb, new air filter, new muffler & exhaust (no cat), oil changed, new PCV valve, plugs checked and looked good (checked gaps too), put premium fuel, still not passing.

He's getting a little stir crazy and wants to drive this beast legally.  Where to go from here? Not sure if this post will send me a notification of a response will give my e-mail below.

mziccardi@cox.net

Thanks a million,

Dad Z.

[jaredts]

What is your idle rpm? How did you adjust the idle mixture screws?

[roundhouse]

There are some tricks
Retard the timing
And ethanol fuel will help
Don't idle the engine while you're waiting in line

And did your truck come from the factory with a cat?


Sent from my iPhone using Tapatalk

[Don5]

The only advice I can give you is to repeat what someone else says. Someone else recommended that you drive the truck for like an hour and get it nice and warm. Blow the carbon out of it. You do not want to go in with a cold engine. Sorry that is the best I can do.

[Irish_Alley]

hows your timing advance set up? (ported or manifold)
do they just do a idle emissions or do they do a high idle?

[oldeagle1]

Irish, Don5, Roundhouse, Jaredts,

Thanks a million for the responses.

1.  Sorry to be so new at this, however at 53 I have learned a few things, it's better to admit my ignorance up front.  I generally know what the timing is, yet know nothing about "timing advance setup".  Just learned what rejetting is and how to do it, have not done it yet.  I have been told by Edelbrock to rejett and by another reliable source to rejett.  However, the timing may be an issue too.  Does the test results from the emissions test tell us where to start:

Failing = Hydrocarbons(HC) Reading:   1st Idle Reading: 641, 1st Idle Standard: 350
                                                              Precondition Reading: 346, Precondition Standard: 300
                                                              Final Reading: 605

Does Pass Carbon Monoxide (CO):  First Idle Reading: 0.62, Idle Standard: 4.00
                                                        Precondition Reading: 0.87,  Precondition Standard: 3.00
                                                         Final Reading: 4.00

2.  They put it on the rack and run it at different RPM's.  I can not remember if they put in gear or not and went up to different speeds though.  They definatly tested it at differing RPM's.

3.  No Cat from factory, just had new muffler installed and they told my son it did not need one, so he went without it.  I think it's better without because we want to get it to pass emissions and register it in Maricopa county.  As I understand it we had a Cat and it was running rich it would fill up quick anyway and become ineffective.

4.  We adjusted the front idling screws by closing them completely down till it almost stalled out then opened them about a 1/4 turn.  I think that helped us pass some portion of the testing.

5.  I do not know what the idle RPM's are at idle, because it does not have a tachometer.



mziccardi@cox.net

Matthew Z., Scottsale AZ.


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