Most newer cars and truck for years have had the EGR valve, so why does unplugging on the 6.7 work?

What is the main function of the EGR?

I have read on this fourm that a new Fooler EGR is being developed hos is this project comming?

 

All the fooler is going to do is allow you to unplug the EGR without tripping the CEL. It can still be unplugged in the meantime.
The EGR system does more than just pump that nasty soot back into the engine a second time. It also retards the engine timing which causes the engine to make less power and require more fuel to get going. The EGR also causes the DPF and CATs to clog up quicker which in turn causes more regenerations which use an incredible amount of fuel. Unplugging the EGR automatically bumps the engine timing back up so you need less fuel to get rolling. It also makes it so you don't need to Regen as often. This also uses less fuel. I don't fully understand yet why it causes less regens because the soot is still pumping out the exhaust but maybe it is cleaner the first time it burns than it is the second time around........

 

When you do any mod that produces a CEL how do you tell if the thruck is experienceing troubles that would otherwise cause a CEL?

 

You don't unless the truck starts running badly. Most of us check codes on a regular basis just to make sure there are no other issues there other than the codes from doing the deletes....

 

Would it be possible to plug the EGR back in and see if the light turns off then unplug it again? If that's the case that'd also be a simple way to see if anything else is causing the CEL

 

Some guys have discovered that plugging and unplugging it too often is not good for the ECM. Once in a while would probably not hurt anything but once a week or so will confuse the computer...

 

For the most part EGR valves have NOT been used in years on gas engines.I bet a couple of decades or better.Its OLD technology.Real old.

 

Almost every new car I work on has an EGR valve....has not been eliminated on new cars.

As for why car use them....high combustion temps on gas engines cause higher levels of oxides of Nigtrogen. By using EGR you can reduce combustion temp during non-essential operation (cruising, non-power loads), by lowering temp you drastically lower emission levels of NOx.

Diesels use it for NOx as well which causes photochemical smog.

http://en.wikipedia.org/wiki/Exhaust_gas_recirculation

 

Was in the auto repair end almost 30 years.Retired in 2001. Egr valves sure were NOT on the product lines I handled in the previous decade or onvery few.They were eliminated and different ways were used to get the same effect.I handled lots of late model GMs,Nissans,Isuzu,Dodge,Mazda etc.My 1998 1500 Ram egr was done away with after 95 model year on 318/360s.Maybe I just didn't see them but by 2001 egr was a term,part of a past era.I thought EGR as in the external donut shaped valve was in a dinosaur era.First ones appeared in the mid 70s Different programs,intake systems etc.performed the same desired affect.Like the old smog pumps that haven't been used in forever.Anyhow I think that the EXTERNAL EGR and the DPF is not a very sophisticated way to handle exhaust gasses.

 

While I can't speak for Domestics...I can tell you with 100% certainty that Mazda, Nissan, Honda and Acura all still use EGR on most of their products. I can even provide part numbers and prices if need be. They are not a thing of the past and have become more reliable than yesteryear as well.

Nissan stopped using EGR on some of their products around 2005 and Mazda...would have to look at the manuals. Honda and Acura still use EGR even on their 2009 models.

 

I recently replaced the EGR valve in my mother's '99 Expedition for her so I can say for absolute certainty that EGR's were in SOME domestic vehicles as recently as 10 years ago. I am relatively positive that new domestics are still using an EGR of some kind as well.

As for why unplugging the EGR works on the 6.7L CTD...IMO, it is a matter of programming. Dodge has programmed the EGR on these trucks to run nearly 100% EGR through the engine at all but full-throttle situations. That means while you are putting around town, your truck is not taking in hardly any clean outside air at all; it is running on almost pure exhaust gas. No wonder turbo's are clogging in 5000 miles and the such. That is the no.1 reason why most unplug their EGR; to prevent their truck from having to visit the dealership every other week for service. The fuel economy benefits given by the advanced timing after unplugging are a welcome side benefit. Until Chrysler can improve the electronics that are operating this emissions equipment, it is going to continue to cause detriment to the owner of the vehicle unless they keep the throttle WFO at nearly every occasion.

Just my $0.02 (which i need a receipt for. tax purposes. this economy has me charting charitible donations at every blink of an eye...)

 

I'm sure some engines need EGR but for the most part the real efficient motor designs and other technology found OTHER ways to emit cleaner emissions then injecting exhaust back into the intake/combustion chamber.Maybe some had to go back to using that system as emissions standards got more stringent but when I was in the industry the EGR way of doing cleaner air was considered way old school.It appeared more then 30 years ago.

 

Wifes 05 Ram 1500 w/HEMI just had EGR replaced a couple months ago. So I guess Ddoge still used them in 2005.

 

Some manufacters stopped using EGR on some engines but I believe in the lastest round of emission standards they were needed again. The only way they got away without using them was through cam timing and alot of overlap. The new variable valve timing has helped elminate Egr again. At any rate the affect is still there just with VVT the overlap can be taken out at high load where they don't have to worry about emissions.

 

It's nice that you guys want to debate the existance of EGR on gas engines but I think we can state as a fact that there is definitely one on every 6.7 CTD that leaves the factory.
Why does unplugging it work? Who cares? It does and it give 99% of trucks better mileage. I don't know why a person would not unplug it given what it does to your engine.....