6.4 Hemi EGR questions

[EriikK]

The 6.4 Hemi (at least '14 and '15 2500's, IDK about the rest) have this big EGR cooler in the valley and lots of associated plumbing. The book even describes a cleaning procedure that is supposed to be done every 60k miles. Remove intake manifold is first step, to get to the thing. Yeah right, like everybody is going to do that.

What happens if the EGR cooler gets clogged up? Is that actually a good thing or does it throw some code and make a problem? In the old days we used to think that EGR was evil and letting it get clogged up was just fine. Is that still true? In MI I don't have to pass any smog test.

I have the intake off already, actually I have the engine out of the truck, so I could clean this now if I really want to. Should I? And if so, what is the alternative to the special Mopar cleaning fluid? something that dissolves the carbon and gunk I guess, but I don't know what.

 

[DILLIGAF]

Just delete it

 

[kurek]

Am I literally the only person on Earth who has never had a problem with EGR?
Why do you even have your engine out of a truck that's only 7 years old? The engine's never been out of my Mustang and it's 30 years old with a quarter million miles...

 

[EriikK]

Just delete it

Yeah. But then do I need to mess with custom tunes and unlocking my PCM and stuff? Maybe easier to just let it get clogged up naturally.

 

[EriikK]

Why do you even have your engine out of a truck that's only 7 years old?

Yeah my '02 Ford 7.3 E350 has a quarter of a million miles and no major issues. But this Ram 2500 I bought at auction has a bad rod knock at 145k miles so here we go.

I'm not having problems with the EGR, it's just on my list of decisions to make as I prepare the new used engine to go into the truck.

 

[kurek]

I suppose the decision is yours to make, EGR is unfortunately very misunderstood and either I learned an accurate analysis in school or I and my professors are dumb - I'm willing to accept reality whatever it is.
It seems most people view EGR as "some smog thing, Forget it!" and it's true that it reduces both oxides of nitrogen in exhaust and total carbon emissions but it does that by improving combustion quality, ignition timing consistency and volumetric efficiency of the engine and in doing so improves part-throttle response and part-throttle fuel efficiency. EGR is never active at idle and never active under heavy throttle so it can never impact power output under high throttle (i.e. it cannot cost you power) . The working mechanism of EGR is to restore your dynamic compression ratio under high manifold vacuum so your pistons have something to compress and the most readily available source of inert (oxygen depleted) air is from the air that was just inside your cylinder a fraction of a second ago.
If you're not burning oil or running rich you should have no particular source of soot or coke in the EGR and it should not get plugged up really for the life of the vehicle.

Plenty of people remove EGR and say they don't notice a difference but nobody's got a butt dyno calibrated tightly enough to observe 5% difference, nor is anyone keeping fuel records that precise. It's not going to make or break your life one way or the other and I really don't care if you keep it or ditch it but at least understand it before making that choice.

 

[Jeepwalker]

It's your truck obviously, but personally I'd take the path of least resistance, clean it and put it back on. I've known a couple guys who dumped a lot of man hours trying to get deleted engines to run 'good'. Maybe it will run fine, maybe it won't. How much energy do you want to put into it? Esp after a fresh 'rebuild' ...if it doesn't run right on start-up, then you don't know if it's something else, or the EGR.

Once you get the engine issues fixed, put some miles on it, then maybe do a delete (at least you've established an operational baseline)

 

[EriikK]

You all are making a lot of sense. Thanks. I'll leave it stock, the path of least resistance.

Thanks for the technical explanation, Kurek.
Maybe another way I could think of it is "badly done EGR from the 1980s was evil, modern computer controlled EGR is OK."

 

[22hemi13]

A Hemi has eve cooler lolololol. Whatttttt