77 FI Bug Emissions

I failed for hydrocarbons. So I turned the adjustment screw on the flowmeter one way and it went high. So I tried turning the other way and the reading was even higher. ( I went 3 times through inspections, after making adjustments) What else should I check? What about the air filter ? Will removing it affect the HC's?

HC is unburned fuel. Have you changed your oil and filter just before the test? If no, do it. How old is the CAT? Did you get it darn near red hot before the test? How is your coil? A weak spark will raise HC.

That screw only affects idle mixture; if they tested at other RPM or under load it will have no effect.

Things that might be at fault: Pressure regulator Injector leak #3 cyl head temp sensor Weak spark/misfire Timing/advance Vac leaks (hoses)

These things are not easy to track down without exh analyzer.

Speedy Jim

also - try taking the air filter out for the test - more air , les unburned fuel !

If it was close, try an E-10 blend. Dennis

Is this in California? How is this emission testing done? At idle & fast idle, or simulated driving conditions?

What is the compression of all of the cylinders? Tune it up with new points plugs wires cap and rotor. Change that air filter. Adjust valves properly Make sure that the timing is not too advanced. Make sure that there are no vacuum leaks especially those fuel injector seals. Fresh oil change

Running some SeaFoam either in the fuel tank for a slow cleanup, or let it enter the engine slowly through a vacuum lead will allow for a faster cleanup of the valves and piston tops.

Yes find an exhaust analyzer to help determine what makes a difference. ;-) AFAIK small incremental turns of the flowmeter will usually make changes in the CO and HC. CO and HC can work hand in hand.