I have a 91 f150 with a 5.0l with a rebuilt engine from a 94. I have a mild cam, headers and full exhaust. When I had the exhaust work done the pipe going down to the exhaust for the air injection was eliminated. Wondering what problems this could cause? Maybe I should just get rid of the EGR and smog pump? Wondering what others think I should do and if I delete EGR and smog pump how would I do that without causing other problems? Thank you for your knowledge!

 

The AIR pump supplies the Cat with air to "warm" them up. If you no longer have cats or no longer have stock cats you shouldnt end up with any problems. Do you still have the EGR tube off the exhaust to the valve? If you dont have that either my suggestion would be to leave the EGR attached but put a block plate between the valve and the Intake Mani. To prevent any codes poping for the lack of the EGR valve. But will also get some of the extra emissions junk out of the way. As for removing the Air pump I know you would need to have a shorter belt and it should not have any negative effects. At this time your air pump isnt doing anything anyway. As for the length on the shorter belt I dont happen to know the length Im sure some of the other that have already removed the pump can chime in with the length.

 

I no longer have cats or the tube from EGR valve to exhaust. So I'm thinking I will take off the air pump and fit it with a shorter belt. Also I will use your block off plate idea. The other thing I was wondering about is the different vacuum valves and tubes in the back of the engine. There are vacuum lines and hoses right behind the plenum. I'm not sure how they work or what they do. I believe they work with the AIR pump? Should I just remove them and plug all the hoses up?

 

Thats one Im not sure on. I have never looked at the 5.0L AIR Set up. So that Ill haft to let someone else answer.

 

if you dont have emissions dont worry about it. i ripped all that off my race truck and it runs ***** to the wall. you may suffer mileage wise but doubt it. think about it, all that crap is recirculating waste and hot air. i cut the return tubes off my cats on my dodge and no CEL light even. dont quote me but try it yourself, if it creates a problem back track.

 

The crossover tube at the back of the heads can be removed. The holes in the back of the heads can then be plugged with a pair of 5/8-11 x 3/4" long bolts. Leave the vacuum lines that supply vacuum to the TAB and TAD solenoids, but plug the top port on each.

If your FEAD has the upper idler with the tensioner located just below the alternator, you'll need a 94" belt (940K6). The routing of the belt is as follows: from the crank pulley around the water pump pulley, to the ps pump, to the ac compressor, under the tensioner, to the alternator, then back to the crank pulley. You won't use the upper idler pulley in this configuration. If that is hazy, I can get a picture for you.

-Rod

 

Thank you for clearing that up. Does the belt routing change at all if I remove the ac compressor as well? It looks like if I get a smaller belt and don't have an AIR pump and the ac compressor I can run everything the same way by just skipping those components. The belt might run kinda close between the water pump and the crank pulley but it should work. The solenoids you mentioned are those the air valves behind the plenum? Or are you referring to the electronic components mounted on the drivers side valve cover?

 

what about the bottom vac line? where does that run to exactly? I have the EGR blocked off and all the smog removed and the top lines capped, but i am not sure where the bottom two went to. I taken out the plastic vac resovior, but i think i am going to reinstall it to keep a vac source for WOT for the FPR and other things

 

Without trying it, I'm not sure how the routing will work without the AC compressor. I kept mine...it gets hot here in the summer.

The solenoids I referred to are mounted on the bracket above the driverside valve cover. The valves behind the plenum can be completely removed.


The bottom vac line on both solenoids supplies vacuum to the solenoids. IIRC, they receive vacuum from the upper intake. Leave those lines, cap the top ports on each solenoid, and keep the solenoids plugged in to prevent a CEL. I would definitely keep a vacuum reservoir of one form or another.

-Rod

 

fordfuelinjection.com has plans that you can just wire in a 75R resistor to the TAB, TAD, and other EGR parts to fool them...and is what I exactly did on my MarkVII lincoln, worked perfect. Ditched all that smog stuff.

And i will do it to my truck as well, and ditch the cats, and put smaller pullies, and ditch the air pump.

 

what did you use to block the exhaust manifold hole, and where did you get it? what size?

thanks

 

A 3/4" pipe cap is what I used.

 

I'll play devil's advocate here, the AIR system -- who cares I guess. EGR saves you money and could screw up how the computer "thinks" when running the engine. The EGR recirculates waste, sure, but the "waste" is nonreactive and decreases how hard the engine has to suck (vacuum-wise) to inhale enough air.

Removing the EGR will make the engine work harder to inhale when you're at cruising speed. For example, you're cruising and only need 20hp but you're running at 2000 rpm which needs "25hp" of air in volumetric terms (2000 rpm * # of cylinders * cylinder volume). Without EGR, your engine will need 25hp of "air" but it's expending (wasting) 5hp to pull air past the the throttle body. EGR replaces the 5hp of air (based on volumetric needs) with exhaust and the engine doesn't need to pull as hard against the throttle.

At that point the computer is expecting (for example) 20hp worth of fresh air plus 5hp (of air volume) of nonreactive air but you're giving it 25hp of reactive air without EGR. That equals a lean condition, which doesn't save gas, instead it gets too hot and doesn't run right.

The AIR system is fine to delete I think, it only monitors it at idle when warming up (in terms of O2 sensor readings). EGR is a different story. The EGR system is one of the best things to ever happen to internal combustion engines.

Good luck.

Edit: for a little more color, consider: your computer thinks it's in "EGR mode" but senses a lean mix. "Why the heck is it lean?" okay let me adjust the fuel trim for ALL modes. So computer thinks it should not trust the O2 / pulse width / MAP / EGR fuel:air tables and runs richer just to "be safe". That means more fuel consumption and a dirtier engine. No big deal if it's a racecar and only sees WOT a quarter mile at a time. But a vehicle that runs on the street for "normal" driving patterns? -- not so great. Sorry for long-winded post.

Edit2: haha, just noticed the original post is 6 years old. Apologies for playing "devil's advocate". It's not the end of the world to eliminate EGR, but it does serve the purpose I describe above. Too many BudLights = sloppy internet discussion (with myself)... Hehe

 

The egr never helps with mileage. It quenches combustion. It cools the combustion chamber to stop the formation of nitrogen oxides. A good fuel injection system with a three way cat eliminates the need for one of these power robbing pieces of garbage.

 

maybe i should block off my egr too!