So I took my 1984 Ford Econoline E-250 van into smog today and she failed. This is the first car that I've ever owned that even came close to failing so I'm more than a little irritated. It's a carburated van, with a V-8 (302 cu.in.) and an auto tranny. Everything is completely stock and the van has 85,000 miles on it. New O2 Sensors about two years ago and a recent tune up (plugs, wires, cap and rotor).

Emissions Readings:

at 15mph
HC 125 MAX: Measured - 67
CO% 0.79 MAX: Measured - 0.00 (WHAT THE HELL?)
NO(PPM) 1062 MAX: Measured - 1343

at 25mph
HC 96 MAX: Measured - 64
CO% 1.00 MAX: Measured - 0.00
NO(PPM) 1073 MAX: Measured - 1163

I checked the archives and it looks like if I had high CO% and NO that I would need a new cat. However, the CO% is zero.....does that still mean that the cat is the problem? Any thoughts? Idles perfect...drives great.

 

whoever tuned it up did soemthing wrong if it was within the last few months.

 

You might want to try another catalyst. The designed lifetime for that model year was 50,000 miles, and carbureted engines were much more prone to clogging cats due to less precise fuel delivery. An abnormally low CO value, along with a high CO2 and O2 value would indicate an exhaust leak/dilution. What are your other measurements?

 

Seems to me like she's running lean. (High 02, low C02)

 

Thanks for the replies so far guys. The other measurements were ...

at 15mph:

CO2% - 12.8
02% - 3.5

at 25mph:

CO2% - 12.9
O2% - 3.4

I was kind of hoping it wasn't the cat....but it looks like I may have to bite the bullet. The only other thing I can think of is the EGR valve. I beleive its functioning (otherwise i would think the CO% would be higher)...but i'll spray some carb cleaner in it and give it a go first.