I have a completely stock 84 fb 5spd with a new cat from magma flow, newer plugs,cap am rotor. I am failing California smog. Here's the issue I pass if the guy takes the air cleaner lid off the carb but fail when he puts it back on. Any ideas?

 

How dirty is your air filter?



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Ok so we tested the cr without an air filter even in it and it failed but would still pass without the air cleaner lid on it. But the smog guy won't test it without the lid.

 

Oops *car not cr

 

then the engine is needing hot air to complete combustion, ie it's a hair too rich. lean out the idle mixture screw(bottom screw, center of the carb on the driver side) about 1/4 turn clockwise and see what happens.

 

Leaned it out to just above where the car would die and it gets closer put still the same condition

 

can you list what the car is putting out emissions wise from the test sheets?

 

15 mph- hc max 104 measured 160. Co max .89 measured 2.03 No max 834 measured 43
25 mph- hc max 86 measured 69. Co max .69 measured 1.64. No max 715 measured 39

 

check the smog pump and ACV.

 

Ok what the heck, took it to a guy to do a test run and diagnostic. He hooked it up an passed with flying colors. No issue what so ever. Nowhere near the last guys numbers.

 

could be a number of things that control the smog pump circuits, that somehow weren't giving you issues during that last test.

i would remove the ACV and try to clean out some of the carbon.

 

That I will do just to be sure, it passed smog but I want to be sure everything is right if possible. The numbers were really low on the test.

 

Thank you for the help