Pre-98 EGR Bypass How-to

[ButtonPuncher]

To do this mod, you need...

A small pipe cutter (available in the plumbing section of your local hardware store)
22mm or 7/8" crowsfoot wrench
A K&N 62-1340 filter. (Or any other that will fit a 5/8" O.D. pipe.)

I purchased mine from Summit...
http://www.summitracing.com/parts/KNN-62-1340/

First, unscrew the EGR pipe from your catalytic converter. It highly suggest soaking the fitting that screws into your cat with Liquid Wrench (or any other penetrating lubricant) and waiting 30 minutes or so. Unscrew with the crowsfoot wrench.

My pipe cutter was an Imperial TC1050 from Ace Hardware. It was the most compact one that I could find.

Take your small pipe cutter and clamp it on about 1" or so from the bracket that bolts to the underside of the coil bracket.

Rotate the cutter forward and back. Tighten the cutter a little each time you make a forward/back motion. It takes a while but you will eventually start to see a cut forming. If you keep rotating the cutter in one direction, it may corkscrew down the pipe instead of cutting it. Back and forth is the way to go.

Once it makes it through, you will have a nice clean cut. Be careful because the inside edge will be sharp. (Don't stick your finger in there. LOL!)

The filter has a nice thick lip where the hose clamp goes on.

Push the filter onto the pipe a good 3/4" and tighten down the clamp.

There still a bit of clearance between the filter and the AC line.

K&N logo...

I haven't had a chance to do long term testing on this mod but it should work just fine.

BP

 

[95_Mystique]

nice write up! thanks for posting

 

[zorrex]

I would like to see how this fares with a stock manifold, just for comparison's sake. Nonetheless, good writeup. Update us with how the vehicle runs!

 

[ButtonPuncher]

This isn't a performance modification. You won't get any HP out of it. This mod is so that you can use the SS Weapon-R Cougar header or to keep your intake manifold free of the carbon that normally gets sucked in via the EGR.

I am currently using the mod on a stock manifold with a gutted cat. My reason for doing it was because the EGR fills up the intake runners with carbon that mixes with the oil from the PVC system. This turns into a hard lining of crud on the intake runners. On both of my 100k+ mile Zetecs, the intakes were filled with this crap. There was a good 1/16" to 1/8" thick layer.

 

[zorrex]

This isn't a performance modification. You won't get any HP out of it. This mod is so that you can use the SS Weapon-R Cougar header or to keep your intake manifold free of the carbon that normally gets sucked in via the EGR.

I am currently using the mod on a stock manifold with a gutted cat. My reason for doing it was because the EGR fills up the intake runners with carbon that mixes with the oil from the PVC system. This turns into a hard lining of crud on the intake runners. On both of my 100k+ mile Zetecs, the intakes were filled with this crap. There was a good 1/16" to 1/8" thick layer.

Well no I mean just to compare how the engine runs, because as you know I have raised a couple questions about the practicality of this mod.

 

[ButtonPuncher]

Oh, I see what you are saying.

If anything, I'm guessing that the opposite effects of removing the EGR valve all together would happen. When I had completely removed my EGR on my ATX a long time ago, I noticed a pulsing in certain cruise conditions. It was like I was letting off the gas every other second. I'm guessing that because the PCM was expecting air flow that wasn't there, that it was essentially like moving the throttle plate a tiny bit.

With this EGR Bypass mod, because the engine will be receiving the air that it expects, I don't think that there will be any side effects. If anything there might be a very minor pulsing at cruise like you are pushing down on the gas pedal every other second.

The couple weeks that I drove my 'tour with this mod was during extremely snowy conditions. I really didn't have any nice smooth cruising driving time to really see if there were any side effects of this mod.

 

[amc49]

You are obviously tripping out. You have done NOTHING there but cut off EGR flow. When PCM signals the valve to open you will HAVE A HUGE VACUUM LEAK OF UNMETERED AIR.

Take the freaking vacuum line off the EGR valve and done if valve does not leak. Of course you will post DTCs then.

The PCM expects EGR THERE which is the OPPOSITE of clean air.

The EGR flow does add carbon to intake but even with it blocked off you will get some. It comes from normal running reversion which is present in all engines.

 

[ButtonPuncher]

Nope, I've never done and drugs in my life. I'm sorry but you're wrong...

EGR is metered by the DPFE sensor. A vacuum leak is by definition unmetered air, which this IS NOT. Yes, I am using clean air instead of used (exhaust) air. It's not enough of a difference to hurt anything or cause the PCM to throw a CEL.

The PCM expects a certain volume of air when opening the EGR valve. I have not changed that. The car will run a little leaner because of the fresh air instead of the exhaust, but that's it.

Yes, some exhaust is pulled back into the CYLINDERS due to overlap, but not all the way back through the intake to the throttle body. The normal EGR setup does. Just pull the throttle body off a 100K mile engine and you will see. The entire intake and backside of the TB will be coated with carbon.

This mod WORKS. Doubt me? Spend $20 and do it yourself!

BP

 

[UmmScott]

I understand the mod, but EGR is present on all cars in some way, therefore the manufacturers know that carbon will build up so most of the time they put that info in the PCM to compensate for that. So why change it? If its not broke don't fix it. IMHO

 

[mcgarvey]

I'm with AMC, this is nuts. The EGR gas is normally noncombustible, deoxygenated gas. This causes oxygen to get sucked into the manifold, causing a lean condition. You're asking for a P0171, a poor running engine, or worse, a lean predetonation condition. If you don't like EGR just unplug the connector to the vacuum switching valve for it and get a tune that eliminates the resulting MIL. Don't go screwing with fuel controls. This isn't the 1950s, "hmm sounds like its running lean, turn the mix screw a little more"-- These cars precisely meter the fuel and air induction using both a MAF sensor and an oxygen sensor and this rediculous mod totally defeats that system. If you don't have a basic understanding of modern EFI control systems, stop messing with it!

 

[amc49]

You need to crack a book, the definition of unmetered air is any that has bypassed measurement by the MAF sensor.

'The PCM expects a certain volume of air when opening the EGR valve.'

Where did you get that one? Volume of air is incorrect, a gas enters but no air at all. In fact no volume measured at all. It's deduced indirectly by pressure dropoff as read by DPFE. The volume is variable and unmeasured directly. Which makes use of the word 'certain' wrong too. A CERTAIN (known and calculated) amount can be simply put into fuel/air software maps. No need to be able to control more or less amounts. Ford could save millions by leaving out the control parts.

'Yes, some exhaust is pulled back into the CYLINDERS due to overlap, but not all the way back through the intake to the throttle body. The normal EGR setup does. Just pull the throttle body off a 100K mile engine and you will see. The entire intake and backside of the TB will be coated with carbon.'

Please explain why engines for 50+ years have shown that same carbon buildup, even way before EGR ever appeared on engines. I know why.

'This mod WORKS.'

Where is your evidence and logic structure of and for that? I see none whatsoever................

 

[ButtonPuncher]

You need to crack a book, the definition of unmetered air is any that has bypassed measurement by the MAF sensor.

You really need to try reading slower or something. I said, "A vacuum leak is by definition unmetered air". You just said the same thing!!! Hold crap dude. What are YOU smoking?!?

Where did you get that one?

It's programmed into the f'ing maps!!!! That why when you disconnect the EGR solenoid, or you EGR fauls, your car will pulse when the EGR is normally actuated.

A CERTAIN (known and calculated) amount can be simply put into fuel/air software maps. No need to be able to control more or less amounts.

IT IS!!!!!!!!!!!!!! You guys need to re-read my previous posts. I have explained EXACTLY why this works.

Please explain why engines for 50+ years have shown that same carbon buildup, even way before EGR ever appeared on engines. I know why.

What part of, "Yes, some exhaust is pulled back into the CYLINDERS due to overlap, but not all the way back through the intake to the throttle body." didn't you get? YES, carbon is pulled back but not to the extreme of an EGR system.

I also said...

I haven't had a chance to do long term testing on this mod but it should work just fine.

It may very well throw a lean code over time but I doubt it. Just re-read post #6 for my thinking one this.

I have explained myself over and over and over... :nonono:

 

[amc49]

There is nothing programmed into software map to reflect added EGR gas except timing control. The timing gets advanced when EGR insertion occurs. Not necessary to correct fuel map because EGR is NOT burnable, it does not tilt the F/A mix except by dilution. The burnable ratio stays the same, you either get that or you don't. Nice try with the posting of your PARTIAL statement taken out of context. Full sentence I believe was......

'A vacuum leak is by definition unmetered air, which this IS NOT.'

Caps YOURS, I rest my case. How convenient of you to miss those words. Air going into the EGR port is unmetered, again you either get it or you don't.

'It's programmed into the f'ing maps!!!! That why when you disconnect the EGR solenoid, or you EGR fauls, your car will pulse when the EGR is normally actuated.'

I have 2 zetecs running around right now with EGR defeated and they both run perfectly.

The statement I made about carbon in intake went right past you, I'm not surprised. Some of the carbon does not come from EGR.........................

What you have done with that 'project' is to screw up your car. No logic applied there at all. I sure hope you don't work on other people's cars.

 

[zorrex]

Most of the carbon comes from the EGR.

This isn't technically a vacuum leak, because the EGR will still be getting the correct amount of air when it's needed, but it'll be clean, combustible air rather than previously-combusted gas. That's really the only difference. It's not as though tossing a filter to cap off the EGR line magically opens up a continuous vacuum leak. How is it any different? The only thing that is different is the quality of the air entering, but even so, EGR is only sometimes incorporated, as has already been said.

 

[ButtonPuncher]

EXACTLY!!!!!! Thank you Ian.

There is nothing programmed into software map to reflect added EGR gas except timing control.

Yes, there is. That is why you get the pulsing when you just disconnect the EGR valve.

'A vacuum leak is by definition unmetered air, which this IS NOT.'

Caps YOURS, I rest my case. How convenient of you to miss those words. Air going into the EGR port is unmetered, again you either get it or you don't.

I was saying that this mod IS NOT a vaccuum leak. I wasn't trying to pull anything. Again, the flow is monitored by the DPFE.

'It's programmed into the f'ing maps!!!! That why when you disconnect the EGR solenoid, or you EGR fauls, your car will pulse when the EGR is normally actuated.'

I have 2 zetecs running around right now with EGR defeated and they both run perfectly.

Bullcrap! There is no way in hell that you disconnected your EGR without programming.

The statement I made about carbon in intake went right past you, I'm not surprised. Some of the carbon does not come from EGR.........................

I will repeat myself yet again for you... What part of, "Yes, some exhaust is pulled back into the CYLINDERS due to overlap, but not all the way back through the intake to the throttle body." didn't you get? YES, carbon is pulled back but not to the extreme of an EGR system.

What you have done with that 'project' is to screw up your car. No logic applied there at all. I sure hope you don't work on other people's cars.

If you had actually read my previous posts, I have explained my logic. Over and over and over and over.... :nonono:

I wouldn't have posted this mod if I thought that it would harm anything or anyone's cars.

I'm starting to think that you are a troll that just wants to start a fight.

 

[amc49]

Nothing personal but if zorrex your backup you are 'in it' so to speak. Look around this site and find how many times he's been totally lost.

Now you are calling me liar. Well, time for me to pack it in. Suffice to say when I passed your 'mod' around at Texas Motors Ford-Fort Worth today the mechs thought you're, well, the word idiot was used.

I'd bet I've built more engines than you have, say hundreds more. Time for me to stop, they're right, I begin to look like the fool I'm talking to, no one can tell the difference.

Good luck, you're gonna need it...............

 

[95_Mystique]

Alright guys, there is no need to get nasty with eachother. You both have valid points. With this mod, you do have extra o2 going into the combustion chamber, which is burnable, meaning it leans out the mixture a lot. with lean mixtures come higher heat, therefore increasing NOX, and reducing life of your exhaust valves. The mod though wouldnt count as a vaccume leak though. The PCM knows when it opens the EGR valve, and the O2S would moniter the change at the same time, so the PCM wont throw up a CEL. It only knows if its getting extra O2 if there is a leak after the EGR valve or if the valve is stuck open. If anything, with the extra o2 coming in thru the EGR, it would tend to keep the EGR valve open during a cruse, and if it keeps the EGR valve open too long it could throw a CEL.

 

[mcgarvey]

My next two mods: this and a whistle tip.

It's the WOOOO WOOOOO

 

[amc49]

Nothing personal player #3, but if this is the best you got you need to stay home too.

'The mod though wouldnt count as a vaccume leak though. The PCM knows when it opens the EGR valve, and the O2S would moniter the change at the same time, so the PCM wont throw up a CEL. It only knows if its getting extra O2 if there is a leak after the EGR valve or if the valve is stuck open.'

I can find so much wrong with that it's not even funny. Just where do you guys get this stuff??? No wonder so many of the cars this site have so much trouble. You're hopelessly lost.

Save one of those whistles for me mcgarvey, these boys are flat tripping me out. They should consult Webster's and define the 2 words VACUUM LEAK and see if they can figure out what that means.

On second thought, maybe they can't. HOO boy...........

Here goes AGAIN. FORD........you remember them right?..... defines unmetered air as ANY that has not been measured by the MAF unit. EGR does not count because it is NOT AIR, as soon as air goes through that opening it IS AN UNMETERED VACUUM LEAK. If you can't grasp that you need to stay out from under your hood. Your car will thank you for it.

 

[mcgarvey]

Yeah this is just flat out retarded. No point in arguing about it anymore. If a person thinks this is a good idea they should stick with taking their car to a professional to have it worked on. I work on cars for a living (at a toyota dealer) and some of the biggest hack jobs I've seen are done by the do-it-yourself crowd. Some so bad you look at it and wonder "They let people like this drive cars?" AMC it sounds like you're a mechanic from what you said in your earlier post so I'm guessing you see a lot of the same.


I know for some reason you guys think that a little extra air is not a big deal, since the o2 sensor will sense the lean condition and increase injector pulse to compensate. You're forgetting that the MAF is the another sensor the computer looks at for fuel control (and one of the only ones when running open loop) and this is bypassing it. It's a vacuum leak, plain and simple. And it's not OK to be running " a little lean", you're asking for predetonation, burned valves, and you're releasing harmful pollutants into the air that I have to breath. Like I said, if you really don't like EGR for some reason, just unplug the electrical connector to the VSV.