The Rusty Gear

Busted my EGR. Looking for options. I heard some people "block" their EGR??? What is involved and is that an option in my case? (see photo)

The Rusty Gear

Too much rust and a pipe wrench.

Recirculating exhaust into the intake . . . Will stopping this likely cause an increase or decrease in fuel economy (ALL the fuel gets used vs higher proportion of "clean" air in combustion chamber) ?

mike_d

no, it's not to burn fuel that didn't get used the second time around. the idea is that exhaust gasses don't burn (they're already burnt). so if you add some inert gasses to the cylinder and it dilutes the oxygen and causes everything to burn cooler. cooler combustion temps form fewer nox and hence less smog. however it's less efficient and lowers milage by about 10% or so. with blocked egr you'll not pass any smog tests in your area, so make sure you can easily put the egr back on for tests. i'm actually planning on bypassing my egr so that i can get a bit better milage.

The Rusty Gear

Smog tests? Ha! In Alberta we don't even legally need a catalytic converter (so I was told at the muffler shop who cut my rusty old one out)

Epic Ed

I just by-passed mine (literally - today). A buddy of mine did it to his and it runs great, but it's unlikely that I'll pass emmisions without putting it back on. Canada may be another matter.

Ed

mike_d

cool. was it easy to do? more importantly, will it be easy to put back on and not look like you messed with it. in co, we get a visual inspection before the real emissions test.

Highland Runner

I believe the engine will knock pretty bad without the EGR, and cause bad things to happen to the pistons.

Epic Ed

Not the case for my buddy's ride. He has a '90 4Runner and has been running with that damn thing off for nearly a year -- no problems (that I'm aware of). Aside from the fact he's a 2nd Gen. 'Runner mod freak, he's also a mechanic and has been the guy who does the work on my ride. Coule he be wrong? Possibly. But I know the removal of the EGR is at least partially responsible for the improved gas mileage and increased throttle response.

I would be interested to hear from others who have done this mod, and to see if anyone can corroborate your concerns. Anyone? Is the ERG more than just a ploy by the environmentalists to given them a false sense of cleaner air and in the process deprive us of precious HP?

Ed

mike_d

<off topic rant>
i'm glad you say this. i'm actually a pretty avid environmentalist (even though i drive an suv as my daily driver). the problem with most environmentalists is that they're not actually scientists/engineers. so to them "lowering the nox at the tailpipe" is a good thing, and the only thing they try to optimize. i've read a couple of reports, that if you factor in the lower gas milage, things like egr are not much help and in some cases hurt the over all pollution coming out of the car. (same with ethanol in gas.) i wish that the crazy environmentalists that are working on pushing legislation through would consult scientists and engineers so that we can actually improve the quality of the environment rather than just pretend we are.
</off topic rant>

The Rusty Gear

I remember reading somewhere that the EGR is not always "ON", that it does not recirculate the exhaust gas when the engine is under heavy load. If this is true, then there should be no issues with knocking because your truck is already operating with the valve "blocked" at times?????

Highland Runner

I think its just the opposite. The valve is closed at idle/low vacuum. When the throttle is opened the vacuum pulls the valve open. This is why some cars run like crap at idle-because the valve gets stuck open.

mike_d

isn't vacuum inversely proportional to the throttle position. i.e. at idle you're drawing the highest vacuum and at WOT you have negligable vacuum?

Highland Runner

http://www.misterfixit.com/egrvalve.htm the second to last paragraph explains the vacuum thing.
Removal of the EGR vacuum line and capping is all thats needed to do this "mode". However I seem to remember a guy on TTORA that did this, and eventually destoyed his engine. The minimal power increase and mileage isn't worth it.

I think your right about the vacuum at idle etc. I took an EGR apart to fix off an old Nissan I had. There may have been a spring that held it closed at idle against the high vacuum. As the throttle moved and vacuum went down, the spring pushed the valve open.

p5150

I know this thread is old, but I think that there is some misinformation that needs to be cleared up.

EGR operates primarally at idle and low vacuum loads. At higher throttle, the EGR is not operational.

Removing EGR will not damage your engine.