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EGR block, why not just...

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Old Nov 27, 2007 | 01:29 PM
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EGR block, why not just...

Why not just unhook the hoses from the BVSV and and cap em?

From my understanding the BVSV controls the vacum to the EGR valve for it to open. The engine warms up, BVSV opens and creates vacum to the EGR valve then it opens?

Ive been sifting through EGR threads and no ones mentioned this? maybe i have the BVSV's function wrong?

thnx
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Old Nov 27, 2007 | 01:36 PM
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This it out of the FSM

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Old Nov 27, 2007 | 01:36 PM
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So if the BVSV never opens, then well neither does the EGR

wouldnt this be a lot easier than cutting pipes or making gaskets?

****
did some more reading... The vacum for the the EGR system is created right behind the throttle body via two ports, depending on carb or non carb (im talking 22r/e) motors they're named different letters in the FSM'. So in theory if you just capped the two ports you'd disable the entire EGR system completely, leaving it shut.

Time to got get under the hood.

Last edited by drew303; Nov 27, 2007 at 01:46 PM.
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Old Nov 27, 2007 | 01:45 PM
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Originally Posted by drew303
So if the BVSV never opens, then well neither does the EGR

wouldnt this be a lot easier than cutting pipes or making gaskets?
That will sort of work, or just cap/plug the line to the top of the EGR (a BB stuffed inside the vacuum hose works well). Only issue is that the EGR can and will open by itself with a combination of exhaust pressure and intake vacuum. See the extra vacuum hose from the side of the EGR to the modulator? That helps to open the EGR and then just plain old exhaust pressure will push open the EGR spring and open the valve. But no real need to plug it, really does nothing to limit engine power and it likely helps fuel economy a bit at partial throttle.

Advantages of internally plugging the line are that you won't misplace the line (in case you need to put it back on for smog checks) and to the casual observer, all will look normal. Note that plugging the line will probably cause the engine to fail a smog test, at least one where they test that the EGR valve works by manually applying vacuum to it.

Last edited by 4Crawler; Nov 27, 2007 at 07:35 PM.
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Old Nov 27, 2007 | 01:48 PM
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Originally Posted by drew303
****
did some more reading... The vacum for the the EGR system is created right behind the throttle body via two ports, depending on carb or non carb (im talking 22r/e) motors they're named different letters in the FSM'. So in theory if you just capped the two ports you'd disable the entire EGR system completely, leaving it shut.

Time to got get under the hood.
we posted same time so reposted here

Whats your thoughts on that tho 4crawler? Yeah im not how pos/neg the EGR system is for performance seems 50/50 in every discussion here. Just saw that this other approach hadnt been discussed
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Old Nov 27, 2007 | 02:37 PM
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EGR only is supposed to operate at partial throttle. Idea is it feeds inert gas (i.e. exhaust) into the intake to take up some of the volume of air that would otherwise be there, less air = less fuel = lower combustion temps = lower NOx emissions. At idle it is off and at wide open throttle it is off. So only comes into play tooling around town and down the highway were you are at partial throttle, basically makes the engine "look" smaller when less power is needed:
- http://en.wikipedia.org/wiki/Exhaust_gas_recirculation

Only real downside of EGR is that when you add hot exhaust into the intake along with the oil mist from the PVC, you get all that wonderful black goo that coats everything inside
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Old Nov 27, 2007 | 03:24 PM
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It also decreases the efficiency of gasoline engines via at least one more mechanism:

Reduced specific heat ratio. A lean intake charge has a higher specific heat ratio than an EGR mixture. A reduction of specific heat ratio reduces the amount of energy that can be extracted by the piston.
From http://en.wikipedia.org/wiki/Exhaust_gas_recirculation

In laymans terms, "reduces the amount of energy that can be extracted by the piston", means that with exhaust gas(EGR)in your air/fuel mixture, as opposed to a "lean intake charge", your engine produces less power.

The myth that lower combustion chamber temps don't equate to lower power output is just that. A myth.

Truthfully it's, less air = less fuel= lower combustion temps = lower NOx emissions = lower HP/MPG

Thank you very much...
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Old Nov 27, 2007 | 04:51 PM
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My EGR isn't blocked, just not hooked to hoses:




Same gas mileage, still runs the same as before.
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Old Nov 27, 2007 | 05:01 PM
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Why does anyone need to cut the lines on the egr....?
Unless they are so stuck that they need to be cut. I continue to hear that people are needing to cut them and I did not need to do that when i removed mine.

I did not really see any noticeable difference in engine performance as well when i removed mine.
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Old Nov 27, 2007 | 05:35 PM
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From: Pleasanton Ca
Originally Posted by drew303
So if the BVSV never opens, then well neither does the EGR

wouldnt this be a lot easier than cutting pipes or making gaskets?

****
did some more reading... The vacum for the the EGR system is created right behind the throttle body via two ports, depending on carb or non carb (im talking 22r/e) motors they're named different letters in the FSM'. So in theory if you just capped the two ports you'd disable the entire EGR system completely, leaving it shut.
That method will work if the EGR valve isn't held slightly open due to carbon build-up on the poppet seat. I tried your method out and no change was noted because the stuck open EGR valve was allowing exhaust gasses into the intake at all times. However, when I completely bypassed the EGR valve out of the picture, my choppy idle smoothed out.
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Old Nov 27, 2007 | 05:53 PM
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Putting a BB in the vacuum line to disable the EGR is a common thing the Aussies do on the turbo diesels over there to help with the black smoke and a bit more power. Rather than taking the whole system off. I have yet to try it on my 3.0TD but mine doesn't smoke at all anyways and does pretty good for mileage. Better than the stock one did anyway. Might try it when I get some time to properly test it out.
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Old Nov 27, 2007 | 05:55 PM
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I bypassed mine by plugging off the line that is directly on the top of the valve. Since it is not a linear EGR valve it only relies on vacume to operate, so when the vacum source is removed, the valve will not function. I have to pass emissions testing every 2 years so it is not in my best intrest to have to pull it on and off. There is actually a pretty noticeable power increase. I have done it to every truck I have ever owned and the only problem I have ever encounterd is that on 88-95 models the check engine light will come on with EGR codes in the computer, but the older versions don't have that sophisticated of a computer system to throw a code.
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Old Nov 27, 2007 | 07:31 PM
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I disconnected the vaccum lines to my EGR system tonight and plugged everything up with vacum plugs n caps.

no change in response/power etc... Thought maybe on the first test drive but I attribute that to the glimmer of hope i had that i'd actually notice something.

My next day off I'll try blocking it off to the manifold for kicks.
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Old Nov 27, 2007 | 08:25 PM
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I don't know how much effect disconnecting the EGR on a stock engine would make (sorry for assuming that your engine is stock). My truck has a ported head, mild cam, bigger valves, header, full 2 1/4" exhaust, intake, some ignition timing advance, a few clicks rich on the AFM, bored out TB and upper and lower plenums with 89 octane. Disconnecting the EGR valve made a pretty noticeable difference on mine. I just read that your truck was a 22R. I have never tried it on a carb'd engine.

Last edited by Yota82; Nov 27, 2007 at 08:27 PM.
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