Last time, I aced emissions after some tweaking. That was just two years ago so I thought maybe with an oil change and air filter I'd pass, or at least come close.

Uhh... not quite. CO limit 40, TC blew 327!!! Crap.



The driver was very careful to drive smoothly with the throttle (carburetor equipped vehicles send a lot of gas down the intake when you punch the gas a lot).

I suspect that the power valve has, once again, failed. Having to spend $60 on a kit every two years to rebuild the carburetor is stupid. Especially when one considers that a Qjet can retain its emissions-friendly calibration for years without any maintenance. I now officially hate Motorcraft 2150 carburetors.

The numbers and graphs suggest an extremely rich mixture -- leaving unburned gas (Hydrocarbons) and lots of CO in the exhaust. While acceleration counts for half of the emissions results, the contribution of cruise is way too high, suggesting a problem that isn't isolated to one circuit (e.g., idle or cruise or power).



The CO graph is pegged out across a wide range of driving scenarios, which is typical of a power valve that is permanently engaged. (Can you tell I've been there, done that?) You can see CO is pegged during cruise, light acceleration, and heavy acceleration. That shouldn't happen.



The HC graph shows problems on acceleration, primarily, but also shows a lot of unburned fuel pretty much all the time.



Before I shell out the money for a rebuild kit, I need to verify the choke is pulling off correctly and that the aneroid isn't stuck closed. If those two things check out, I'll try to find a power valve separately but most likely will have to get the rebuild kit.

It's probably just as well that they rescinded the collector plate exemption here. I'd rather go through this every other year hell than pollute all the time.

Now that Ethan finished setting me up with the right gear for fuel injection, I'm installing it as soon as I can, believe me. I'm sick of carburetors.