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Thread: EGR Delete --- Can you calm my fears?

  1. #1
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    Default EGR Delete --- Can you calm my fears?

    Hey Guys!

    Love this place! I'm reading what half the people have done or doing to there GMN and it makes me happy! But I'm sitting here having a heart attack over a simple EGR Delete thought.

    So here is my story! I got a pretty much stock 302 (1988) with shorties, high flow 2.5 inch cats and some pass through mufflers. Sound video to come . But I had the shop reconnect the EGR system. Because I'm afraid of some stories from my father of people burning holes in there pistons. I see many people who have done this successfully. However, the stupid weld for this pipe keeps coming apart - the weld is not sticking right to the EGR pipe. They have tried twice.

    I bought the EGR delete resister "thingy" and a cover plate for the EGR. I understand what the EGR does and how it functions. I need a little push over the edge to get me past this fear. I don't want to blow up this near mint 302.

    Do I keep the EGR or do I get rid of it? What is the actual risk of blowing up a piston or burning a hole in the piston?

    The only other MOD I may do is a better air in take from an explorer. I'm not changing cams or anything else of that nature.

    Thanks for the help!

    Car - 1988 Grand Marquis LS 302
    Last edited by ComputerFreek; 06-23-2021 at 10:41 AM. Reason: Added Car

  2. #2
    Lost and driftin' Arquemann's Avatar
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    Well my EGR on my CFI beast has had pretty much every possible variation of unplugged, plugged, connected and disabled.
    I haven't had any adverse effects from it being unplugged.
    I've been running mine with just the valve closed (vacuum line plugged) and the position sensor connected. (I have my EGR solenoids disconnected but I don't think it applies to you)

    Only risk you might get with a malfunctioning EGR system is if the valve gets stuck open. Just slap on the delete plate, resistor and donworryboutit!
    1985 Mercury Grand Marquis LS, "Maisa"
    2008 BMW 530d Touring, "Femma"

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    P31 Pursuit Car Brown_Muscle's Avatar
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    It does offer some cooling, but unless you're running lean for whatever reason, you wont blow a hole in a piston, so you can delete it just fine as Arquemann said. Which pipe are you talking about? Isn't the EGR internal, the thermactor (air pump) has pipes going to the back of the heads and to the cats
    -Phil



    +1982 Ford LTD-S Police Car. Built 351w, Trickflow 11R 190 Heads, Edelbrock 1906 Carb+ RPM Intake, WR-AOD, Full exhaust headers to tails. 3.27 Trac-Lok Rear. Aluminum Police Driveshaft. Speedway Springs+Bilstein Shocks, Intermediate Brakes, HPP Steering Box.

    +2003 Acura CL Type S 6-speed

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    Quote Originally Posted by Brown_Muscle View Post
    It does offer some cooling, but unless you're running lean for whatever reason, you wont blow a hole in a piston, so you can delete it just fine as Arquemann said. Which pipe are you talking about? Isn't the EGR internal, the thermactor (air pump) has pipes going to the back of the heads and to the cats
    Hey! I just had a custom exhaust put on the car. And after markets cats. The pipes that go in the exhaust pipe were welded on the new exhaust pipe.

    Kyle

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    Lost and driftin' Arquemann's Avatar
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    The pipes that go into the exhaust in front of the cats (stock exhaust) are a part of the air pump system, they have nothing to do with the EGR.
    1985 Mercury Grand Marquis LS, "Maisa"
    2008 BMW 530d Touring, "Femma"

  6. #6
    I'm an air-conditioned gypsy gadget73's Avatar
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    All its going to do is produce more NOx emissions and burn a smidge more fuel. The ECM reads EGR position and if it does not open, it doesn't lean out the fuel mix and advance the timing. It will not melt the pistons, damage the engine, or do anything else thats scary or harmful.

    That said, deleting it doesn't actually do anything useful. If the EGR is working correctly, it doesn't take away performance. If its causing problems, its not working like it should.

    now if you're talking about the plumbing down to the cats and around the back of the heads, that has absolutely nothing to do with the EGR system. Thats the thermactor / air injection system. the air into the back of the heads is to warm up the cats more quickly and it shuts off after a few minutes because it screws with the oxygen sensors. Into the cats is for the old style converters to make them do whatever they do. Modern cats don't need this.

    I would not suggest an Explorer intake on a stock engine. Too much intake, not enough motor. People have done it and say that it costs low end torque. Thats all these motors have going for them.

    86 Lincoln Town Car (Galactica).
    5.0 HO, CompCams XE258,Scorpion 1.72 roller rockers, 3.55 K code rear, tow package, BHPerformance ported E7 heads, Tmoss Explorer intake, 65mm throttle body, Hedman 1 5/8" headers, 2.5" dual exhaust, ASP underdrive pulley

    91 Lincoln Mark VII LSC SE, triple black (Timewarp) - poly front bushings, KYB struts and shocks, Holley SystemMax1 lower intake, SilverFox AOD valve body,

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    Quote Originally Posted by phayzer5 View Post
    I drive a Lincoln. I can't be bothered to shift like the peasants and rabble rousers

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    This is great information.

    So @gadget73 or anyone. I guess I'm a little lost.

    How does the EGR get push fumes back in to the air intake? I feel like an idiot asking this... But I thought that is what those pipes are from.... Pulling the burned fumes from the exhaust back to the air intake.. I guess I misunderstood all of this.


    Can skip this next part if you wish:

    Summary of what I have done so far.
    1) Removed Stock Manifolds - Installed Shorty Headers ( https://www.summitracing.com/parts/BBK-1515 )
    2) Replaced stock Cats (4) with two new MangaFlows ( https://www.summitracing.com/parts/MPE-53006 )
    3) Left and Right banks have separate exhaust tubes going to there own muffler - No H or X Pipe
    4) Removed EGR and Installed Block Plate to cover EGR Hole
    5) Installed EGR Fake out plug thing. Makes the computer think the EGR is closed
    6) Had Muffler shop close and weld the pipes that were going to the old converters. (After this- noticed the smog/thermactor pump is now making a wild noise)
    End Skip


    I had the muffler shop close off the pipes going to the exhaust. I thought this was for the EGR Valve... Even they told me it was for the EGR value... but what your saying kind of makes sense - the Smog pump or the thermactor pump is now making a whining sound. I'm assuming thats because the pipes have now been sealed and the pump is now fighting to push air through pipes that don't go anywhere. I've also kept the O2 Sensors - the car always seems to run better with these sensors installed. I always believed that this car depends on these o2 sensors to judge its fuel mix. I was told I was wrong and in this year from Ford, they were only used to turn the idiot light on. I'm hoping they were wrong and the computer is using these to judge fuel and air mix.


    So I guess let me go back to basics here.. And ask stupid questions....

    1) Where does the EGR get the burned exhaust to mix with the incoming air? Or am I messing up this system in my head?
    2) Should I reconnect the lines going to the exhaust from the thermactor pump? From what you said above, i don't need this system because it is for the older cats. Which I removed and installed newer ones. (New Ones: https://www.summitracing.com/parts/MPE-53006 )

    I guess 3) ? 3) Can I disconnect to the thermatctor pump if I don't need it? Should I just reopen the lines and allow the pressure to escape in to the wild?

    4) Did I just "F" up my car?

    5) Is there something I am missing?


    Thanks Everyone for the help! I would review other posts, but I want to make a the correct decision. I don't want to destroy a thermatctor pump if I don't have to.


    Sorry for Spelling or Grammar issues. I'm typing this on a phone!

  8. #8
    Lost and driftin' Arquemann's Avatar
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    1. Stock heads and intake have ports where a portion of the exhaust travels to the EGR spacer and EGR valve. Many aftermarket intakes and heads do not have these ports.

    2. No you shouldn't, because of those modern cats you have.

    3. Since you have new aftermarket cats, yes. At you situation, you're not going to do anything with any of it. You can remove the whole system if you plug the holes in the backs of the heads (and cats). I took off my pump like many others here, as it wasn't long for this world. Don't leave holes in your exhaust lol.

    4. Nope, definitely not.

    5. Probably not. In short: EGR is good to have working, the thermactor crap not so much. You don't need the thermactor at all since you have aftermarket cats. (Thermactors main purpose is to inject air into the exhaust to faster warm up the stock slow cats.)

    Those O2 sensors are important, not as important as in new cars, but still important.
    1985 Mercury Grand Marquis LS, "Maisa"
    2008 BMW 530d Touring, "Femma"

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    Quote Originally Posted by Arquemann View Post
    1. Stock heads and intake have ports where a portion of the exhaust travels to the EGR spacer and EGR valve. Many aftermarket intakes and heads do not have these ports.

    2. No you shouldn't, because of those modern cats you have.

    3. Since you have new aftermarket cats, yes. At you situation, you're not going to do anything with any of it. You can remove the whole system if you plug the holes in the backs of the heads (and cats). I took off my pump like many others here, as it wasn't long for this world. Don't leave holes in your exhaust lol.

    4. Nope, definitely not.

    5. Probably not. In short: EGR is good to have working, the thermactor crap not so much. You don't need the thermactor at all since you have aftermarket cats. (Thermactors main purpose is to inject air into the exhaust to faster warm up the stock slow cats.)

    Those O2 sensors are important, not as important as in new cars, but still important.
    Thank you for your quick response Arquemann

    OTHER QUESTION; from your number 1) Are you saying that the exhast is going to the EGR within the engine it self? Its not using the pipes under the air intake?

    Let me ask you this in a different way:

    Are you saying that you can have a fully working EGR Value - WITHOUT a thermactor pump? (Trying to understand this system)

    Thanks,
    Kyle
    Last edited by ComputerFreek; 06-26-2021 at 04:35 AM.

  10. #10
    Lost and driftin' Arquemann's Avatar
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    I'm not sure what you mean by pipes underneath the intake, but the EGR is almost fully internal, the only visible portion is the egr valve and "egr spacer" behind the throttle body.

    Yes, EGR and Thermactor aren't dependant in any way.

    I'm not exactly sure how the thermactor tube routing is on SEFI, but there are metal tubes going to the backs of the cylinder heads and then the ones that go to the exhaust before the cats. Following those tubes should lead you to some solenoids and eventually to the air pump itself.
    Removing the air pump and its crap is pretty much the same as on fox mustangs, if you want videos.
    1985 Mercury Grand Marquis LS, "Maisa"
    2008 BMW 530d Touring, "Femma"

  11. #11
    I'm an air-conditioned gypsy gadget73's Avatar
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    There is an internal passage in the intake manifold that the EGR gas flows through.



    its that hole in the middle. An equivalent one is in the upper manifold and comes out below the hole where the throttle body and EGR spacer bolt up.

    The heads have holes on the intake side that connect to the exhaust passage. Origiinally it was for the heat choke and to run hot gas under the carb but they were re-purposed on EFI engines.

    thermactor on CFI and SEFI is basically identical, just the pipe on the back of the heads is bent a little different for clearance. The valves also live closer to the pump rather than up on the fender.

    86 Lincoln Town Car (Galactica).
    5.0 HO, CompCams XE258,Scorpion 1.72 roller rockers, 3.55 K code rear, tow package, BHPerformance ported E7 heads, Tmoss Explorer intake, 65mm throttle body, Hedman 1 5/8" headers, 2.5" dual exhaust, ASP underdrive pulley

    91 Lincoln Mark VII LSC SE, triple black (Timewarp) - poly front bushings, KYB struts and shocks, Holley SystemMax1 lower intake, SilverFox AOD valve body,

    1984 Lincoln Continental TurboDiesel - rolls coal

    Quote Originally Posted by phayzer5 View Post
    I drive a Lincoln. I can't be bothered to shift like the peasants and rabble rousers

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    So in summary - most of the time - keep the egr valve. But I can remove the Thermator pump because it was meant to push air in to the cats.

    So remove the thermator pump because I have new cats. But reconsider maybe putting the egr back together.

  13. #13
    I'm an air-conditioned gypsy gadget73's Avatar
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    you got it.

    86 Lincoln Town Car (Galactica).
    5.0 HO, CompCams XE258,Scorpion 1.72 roller rockers, 3.55 K code rear, tow package, BHPerformance ported E7 heads, Tmoss Explorer intake, 65mm throttle body, Hedman 1 5/8" headers, 2.5" dual exhaust, ASP underdrive pulley

    91 Lincoln Mark VII LSC SE, triple black (Timewarp) - poly front bushings, KYB struts and shocks, Holley SystemMax1 lower intake, SilverFox AOD valve body,

    1984 Lincoln Continental TurboDiesel - rolls coal

    Quote Originally Posted by phayzer5 View Post
    I drive a Lincoln. I can't be bothered to shift like the peasants and rabble rousers

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    Thank you all for your knowledge and brain power behind this. Sorry for my confusing wording and getting systems mixed up. I only hope I can return the favor to the group with my knowledge and experience. But I'm yet to be able to do that .

    I have one last question. I've been reviewing other posts and TRYING to dig for this information. I'm trying to find a belt to bypass the thermator pump without a pulley replacement. I found this one:

    https://www.oreillyauto.com/detail/c...-grand-marquis - Effective Length (in): 56-5/16 Inch

    Will this work to bypass the thermactor and still hit the ac pump? If not - I will use the old string trick I keep reading about.

    Thanks,
    Kyle

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    Yeah, that belt is the same length I used on my car when I pulled the smog pump. Works just fine to keep your A/C.

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    I should have added this question to above. I'm assuming this turns the car in to a single belt system - not a two belt system correct?

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    Still two belt. Just eliminates the smog pump so this belt will run on the crank, A/C, and have the single idler.

    I always liked the two belt setup. I figured it gave me a better shot of not being stranded.
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    Quote Originally Posted by Tiggie View Post
    Still two belt. Just eliminates the smog pump so this belt will run on the crank, A/C, and have the single idler.

    I always liked the two belt setup. I figured it gave me a better shot of not being stranded.

    Yea.... I realized after I posted that---- that belt is not even close to being long enough

    Thank you for confirming

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    So I haven't installed the new belt to go around the pump. I wanted to do some testing and see if I can better understand this system..

    Right now - I have the downward pipe that went to the cats disconnected. So you have the pump to the valve. The downward pipe is disconnected and the pipe that goes back to the back of the heads is still connected.

    I started the car in this configuration - after about a 1 to 2 mins the valve opened to the CATS or to nothing in this case.

    My question is - is the pump pumping air in the back of the heads during start up? Is this normal operation?

    Why is it doing this?

    My shop manual tells me how to fix it, but it doesn't tell me why. (LOL)

    Thanks for the information.
    Kyle

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