I have the vehicle mentioned in my sig. I'm replacing the smog pump on the truck, but there's no piping to the heads - it just blows. Would there be any benefit to routing a hose from the pump to the intake before the MAF (like to the filter cover) to make use of the otherwise wasted power?

To be sure, am I correct with the assumption that the pump's intake is from the vapor canister and output to the motor?

Thanks!!

 

Okay, I figured out the airflow of the pump when I got it on. Still wondering if routing it to the airbox would be beneficial for MPG, another pony or two, or both..

 

Okay, I'm going to try it and go from there.

 

The results so far:

Engine stumbles a bit for a few minutes, almost as if it were running without a MAF. Stalls out a couple of times, but after babying it a bit, runs smooth again - maybe adapted to the extra airflow passing through the MAF?

Drove down road - seems to have a very minor power increase. It could be me, but I don't feel like I'm holding the throttle down so far to maintain speed. Haven't tried it on hills yet.

Pulled back into driveway and parked - idled smoothly.

Maybe it will help with MPGs, maybe it will make them worse. Hoping for professional opinion. I have two theories: One, the extra air will aid in fuel atomization/vaporization, adding a little more fuel efficiency through mild semi-forced air induction. The other theory is the computer, via the oxygen sensor may detect too much air in the exhaust, and increase fuel delivery to compensate.

Another question arises - will the extra air increase combustion chamber temps to levels that are bad for the pistons, valves, etc?

 

No, this is a horrible idea, and none of your theories is correct. MAINTAIN the truck the way Ford built it, and it will run properly, reliably, & durably. This page explains how the thermactor (secondary) air system works:

(click this text)

 

Ideally, keeping it in the stock, factory configuration would be ideal. However, when the motor was put in two years ago, the hose/piping from the pump to the heads didn't get switched from the old motor to this one (wasn't me that did the swap). The mechanic said he tried for a couple of hours to get the pipes off of the other motor, then and to do extra work to this one because of broken bolts and he didn't want to sock me for even more labor. So he just plugged the old smog pump and life went on for two magical years until the pump seized up. Not finding a very suitable idler pulley to replace it, I simply replaced the pump.

I did try my idea, but wasn't satisfied with the results and had some concerns with it, so I disconnected it from the air box. It's been running fine since other that guzzling gas (13 mpg). I hoped that the extra air might help that, but it wasn't worth the effort. 100% natural aspiration again, the way it was meant to be.

 

Oh, well - if it's not easy, then forget it. Just tear it up.

BTW
302 ci is not 5.7L, and that truck is not "completely stock".

 

I don't know why I put 5.7 LOL, But "completely stock" is referring to not having any mods like cold air intake, bigger injectors, more powerful ignition headers or anything of the like.

I'll be correcting that.

 

Cold air intake is not a mod - every vehicle sold in the US since the mid-70s comes with CAI from the factory. And the 5.0L already has bigger injectors - bigger than the 4.9L. There is no such thing as more-powerful ignition - the ignition system uses as much power as it needs to charge the coil. Installing a coil that requires more power to charge is a waste of time, effort, money, & power. It will still put out the same voltage & power to jump the plugs' gaps.