[fox81]

The pipe (or whatever you want to call it) from my smog pump to my cat is rotted off and has been that way since I've had it (about 3 years). So my question is, can this effect mileage in any way? Right now I'm getting about 21mpg mixed and I would like to get a couple of more. By the way it's a 1981 thats carbed with the C3.

I can post some pictures this afternoon if this will help any.

[heavy metal]

The smog pump supplies air to the cat vai that tube,it helps the cat be more effecient.

[ExtrmZ]

it shouldnt really hurt your mileage..

[ethangsmith]

Doesn't hurt your fuel mileage directly. However, since the cat is not getting air, it is probably gunking up slowly, which will kill power and fuel economy. If you're in a non-emissions area, get rid of the whole air pump system and cat. Also, make sure your carb is properly tuned. Those 2 barrels can really be a mess if they are shot or gunked up. Rebuild kits are available next day through advance auto.

[fox81]

That tube/pipe fell off the first day I got it. Can't remember if I saved it or not. But right now it's just plugged with a large bolt. I thought about getting rid of the cat, but I don't have the $ for an exhaust right now. I was thinking of building a piece to go in the place of the cat. I started it one day with out it and man did that 2.3 sound mean! (I took it off to see if it was plugged up.) The carb has about a year on the rebuild. So I'm good there. But whats funny on my carb it's "unadjustable", as in the mixture screws but the previous owner drilled one of the caps off it. I've tried messing with it a bit but it seems to be fine as it is.

[ethangsmith]

Yea, being an 81 carb, quite a few of the adjustments have been taken away or concealed. You can still change jets and air corrector jets in it. They are the same as a Weber DFEV carburetor.

[fox81]

In a couple of weeks I might change the float in it but I don't think that will help that much. I was a goof and didn't replace it when I rebuilt. But I have run a couple of cans of seafoam in the gas. I was somewhat unsure of putting it in directly into the engine via a vacuum line. But yeah it being an 81 kinda sucks cause that seems it have been a "transition" year for a lot of things in the mass majority of the auto makers.

[ethangsmith]

Yep, the 81 carbs were the first with the non-adjustable choke and fixed idle mix, which sucks. If you can find a 78-80 carb off a 2.3L, it will have idle mix adjustment and an adjustable choke and will still be a direct replacement.

[fox81]

I just might have to look into that. Who knows, maybe I'll get lucky and come across one. Would it be worth it to do a swap and put an earlier carb and have the adjustments? How much would I gain in milage and maybe even power (rough estimate wise)?

[ethangsmith]

To be honest, not really much of anything.It is just good to have more adjustments so you can fix any rough running issues. As the engine wears, it won't respond like it did back in 1981 when it was new. Being able to richen the idle mix a little and setting the choke richer can really help with the smoothness of how it drives and runs. So really, I don't think you would see more power or fuel savings, just better driveability. If you want more power, try a real Weber DFEV or a 1977 Pinto 2.3L carb. The 77 Pinto carb is the only year the Motorcraft 5200 is totally identical to the DFEV. It has no emissions stuff on it and is jetted pretty nicely. I am running a 77 Pinto carb on my Capri. I had a 1980 carb on and when I swapped it out for the 77 Pinto carb I noticed a little edge in power and it ran a whole lot better. A Weber DFEV will cost you about $285 from Top-End Performance. Import Car Parts and Tuning. Weber Carbs. 818 764-1901 and a reman 77 Pinto carb (If you can find one!!!) will cost in the realm of $100-$200 depending on the quality of the work done. I was fortunate enough to score 2 77 Pinto carbs (one is for salvage parts) out of a box lot of 2.3L stuff. Just some thoughts and ideas for you.

[ethangsmith]

Oh, the quick way to identify a 77 Pinto carb is that it has an electric choke, but no bowl vent (large pipe that connects to the left of the fuel inlet). 78 and later had a bowl vent, 76 and older were aquastatic choke.

[fox81]

Well I just might have to keep that in mind when I get some extra cash. But for now, it will remain relatively stock. But I'll keep my eye open for any Pintos that are up for parts.