I was just about to jump in and type the same thing.

I have none of that crap on my 93 crewcab and it doesn't run rich, or lean, and I still pass emissions just fine.

One can also leave the solenoids wired up but not hooked to anything else.

 

Yeah, mine is pretty much not hooked up right now, and it runs better than it used to, if anything. But I wasn't sure how observant the emmisions guys are here in MD. They do take and look under with a mirror to make sure the cats are still there. Maybe I could just go up and try it w/o putting the small tubes in place, and see if it passes. If not they give a certain amount of time to fix the problem.

So, Fred, you say you have no air pump at all? or just no plumbing to the cats?

Thanks

Bob

 

And to add to that...the air pump doesn't determine the air/fuel mixture, the ECU does that, by means of an adative fuel table (when in closed loop).

I agree with Federic and Eric, removing the air pump shouldn't cause any problems.

 

No air pump at all. The bracket rotted/disintegrated/broke and the tension of the belt pulled the air pump into suicide. I removed what was left and installed a shorter belt, and had no problems. A few years later (last summer) I was having vaccum leaks, so I removed all the vaccum hoses between the emissions solenoids (tab/tad), and put a cap on the vaccum treee that feeds those devices.

Right now, I just have a generic, aftermarket cat with no air lines feeding it, and the EGR valve is also brand new. The Tab/Tad solenoids are still mounted on the plate on the engine and connected to the wiring harness.



Passes emissions just fine. Even though I'm only required to pass an idle test here in NJ due to how it's registered, when playing with a buddy's emissions dyno we measured the output of the tailpipe (for tuning purposes) and it would have passed the full-fledged NJ dyno/roller test with flying colors.

When you start your truck (or any vehicle) it runs much richer until it warms up, and there's extra fuel vapor flying through the cat. The fuel vapor will kill the cat very quickly, as well as cause emissions issues. Pumping air into the cat solves both problems - it allows the cat to burn the fuel vapor from the rich running engine, by adding the necessary air into the mix, which in turn makes the cat night and hot to maintain that function once the engine warms up.

The air pump system is only useful until the EEC realizes the thermostat opened. Then the air pump and related parts are just along for the ride.

Removing all that crap just means you shouldn't have your vehicle emissions tested 30 seconds after starting it first thing in the morning. Give it a few minutes to warm up, open the thermostat, and go into closed-loop mode.

 

[QUOTE=frederic]

When you start your truck (or any vehicle) it runs much richer until it warms up, and there's extra fuel vapor flying through the cat. The fuel vapor will kill the cat very quickly, as well as cause emissions issues. Pumping air into the cat solves both problems - it allows the cat to burn the fuel vapor from the rich running engine, by adding the necessary air into the mix, which in turn makes the cat night and hot to maintain that function once the engine warms up.


Well, that sounds pretty useful to me, I have had a cat go bad, and can't really afford extra expenses. Since I have the tubing, I guess I am back to putting it on there.

Thanks, everyone. Lots more info than I reqested. But still nobody has an answer for which tube is first? Anyone have the Ford emission shop manual for this? Like I said, I am sure I would have bought it, had it not been over 300 bucks.

 

My crewcab has a "Y" pipe that uses the factory cat as a collector for both sides, and was very expensive. The picture I posted above was the final result of using a cheaper, generic cat with a homemade adapter that does the collection. It's made out of 5/16" plate with some hacked up exhaust tubing welded to it forming a cone. If yours is like this, and you can weld (or have a friend who will do it for a beer or two), consider this option. It saves you $200 and you can then use generic cats going forward. Here's the write up:

http://frederic.midimonkey.com/f350-catadapter.html

I'm not sure what "which tube is first" means... looking at your original post that started this thread it wasn't obvious to me. Either that or it's time to refill my coffee mug.

Try again, I'm happy to help.

 

Well, there are 2 tubes feeding air to the cat- just trying to make sure I get the right pipes hooked to each one. I went up to the ford dealer and got a printout that had a good enough picture to figure it out. So, I think I am in business here. finally working on installation- I hope quick enough to avoid tag suspension.

Thanks for all the help and advice, All!

 

Well,

I got to thinking- my '68 mustang had an air pump (Thermactor), way before cats were even on cars. I got out my book on emissions systems, and it said the purpose of the air pump is to add the extra O to the CO to make CO2. Makes sense, I guess that's where we are getting this global warming from.

 

I keep comming back to this issue and it would seem there are people out there that have removed the air pump from thier trucks with no ill effects. But I know with certainty that my 89 was not happy when I lost that air injection on 2 seperate occasions. The fiirst was when the crossover pipe on the back of he motor rusted out, and the second when the pump died. Both times it ran lean and pinged badly under any kind of load once at operating temperature. This truck had no codes and ran fine for many years except for this issue. I'm thinking this may be similar to other issues that people have, like how one guy can advance timing 6 degrees from stock no problems on his 302, while somebody else can't run 11 deg total with pinging. Basically, there are production differences to take into account and some motors run a little closer to the edge than others, and are more sensitivite to problems. I'm not ruling out the possibility this motor didn't have some other issue I was not aware of, but as I said, it ran great and didn't produce any codes.

 

Fred, where/how do I go about posting the picture/description like you did with your exhaust setup? I want to do it with mine when I get it done. Or is it outside of the FTE site?

Thanks,
Bob

 

I had to cut the air pump off because the upper and lower bolts were completely seized. When I could get enough strength on the breaker to move them, they were just twisting... out comes MR. Sawzall. Anyways, what is this shorter belt from? I am not finding a non-air pump model on the Autozone website.

 

I think the shorter belt is just a generic serpentine belt which is a couple inches shorter than stock. Someone else I'm sure can give you the exact length, or you can measure it with a string.

 

Yippee! finally got everything together and went and passed emissions. I will be putting the pix up somewhere when I get the time.
Also, one time when it's cooler, might fool around with changing parts back and forth and seeing the difference with and without Cats and air pump, either at the strip, or with one of those gyro gizmos. Could be fun.

 

i just put the pulley back on mine and the truck runs a lot smoother no notice any power loss or gain. just that it know runs smoother. Not sure on the milage either this is the first tank that i will be running in it with the pulley on