Just bought this '84 Ranger 2.8 L it failed emission test badly. Had the carb rebuilt but still failed On HC to pass you need 220 ppm or lower I was at 410 during hi speed. Idle 220 ppm I was 105. Any suggestions? Help!

Coach17

 

Check that the float is not 'gas logged'. I think they had problems with the 'black fiber' floats of the time. A bum float will give a too high fuel level in the float bowl, and will allow more fuel to get drawn into the engine than normal, leading to excess HC.
Checking the float valve implies checking the fuel level in the float bowl.
Check that the power valve is not leaky. If the diaphragm gets broken by a backfire, it will never go to the 'closed' or leaner mode.
How did you adjust the idle mix needles?
I would also check the the throttle plate shaft has not worn too much, which would allow excess air into the intake, leading to possible misfire which produces HC also.
tom

 

years ago when they had emmisions test here in florida many people couldnt get their vehicles to pass,,, mainly because they would not admit their car had a lot of mileage,,, i had a 80 chevette at the time,, the cat had been gutted and a round plate put over hole,,, when looked at couldnt tell that it had been gutted,, the motor in it was out of a 76 and had all the pollution stuff removed,,,, people would pull in test center and would not say the car had 170,00 or 270000 they would say 70000,,, when i went in with chevette i told them 300000 plus and it passed for the 3 years i owned it,,,, they finally quit the testing when it was figured out it was just a way for car repair places to make money,,, just like old people here in florida who cant get license,, or tags they drive any way,, the same with testing if it dosent pass they would drive any way,,,