nick did you do a write-up on this? if not, can you explain how you did it and why? kinda intersted now that blue brought it up...

 

I think the reason for removing them is because they are 100 a piece and usually only come with a one year warranty. Kinda pricey.

 

My main reason is that I like to keep spares of all the Renix sensors and such like components. Just loaned my spare EGR valve to a buddy recently and don't want to replace it if I can save the cash. Probably a bad reason but it got me thinking I don't have emmisions here like in several other places and can't see that there is that much exhaust flow through it anyway, so thought I would see about eliminating it as a system. Figured that the smog ***** are the reason that we have them anyway.

 

If you find a link post it b/c I would like to read it anyway even if it is for a H O.

 

I'm pretty new to Jeeps, and my last project was an '81 Bronco with a carbureted 302 with no EGR stuff and almost no vacuum lines. My Jeep is a 1987 Cherokee Pioneer with the 4.0 and I was wondering; what vacuum lines do I need, and if I make a snorkel, do I need to hook any of the stuff from the stock air box back up, or can I just plug it up?
Thanks!

 

hook it all back up.

 

No write up. When I had that Jeep it was before I was on the sites. I did it mainly cause the EGR was broke and I didn't have the cash to buy a new one.. I for the life of me can't remember what all I did. Just that I got rid of it... Sorry...

On the 4 poppers they were always imports and was done just to clean the look of the motor up.

 

I'm surprised none of folks with ALOT more basic chemistry than me ever answered this...

By reducing the amount of oxygen available for combustion.

We know we have a static volume of fuel/air mix in the combustion chamber. We also are not using any additional artificial means of increasing the pressure and the fuel air ratio.

So that if exhaust gases which contain a lower oxygen level than air are in added to the mix, the available oxygen is reduced, thus reducing combustion temps.

It also is the reason that the folks with the artificial means of increasing oxygen(turbos,superchargers,NOS) need to watch their engine and exhaust temps much more closely.

 

Thanks whowey that makes good sense.
Blue

 

The Renix motor in my son's XJ would not run without the EGR valve. I probably left a vacuum line open or something else that actually caused it not to run. We were thinking the same (get rid of it) as my 91 HO motor doesn't have an EGR. His was plugged full of carbon so I just snagged one off a donor XJ at the local scrap yard. I never knew about the EGR being gone causing a Renix motor to run hotter....and as we all know you don't ever want to do anything to cause a Jeep 4.0 to run hotter than it already does....LOL.

 

So... why don't mopar jeeps have the egr ?
Better flow ?

 

My guess is the newer ECU in the 90 and newer XJs with the 4.0 HO motor don't need the EGR valve. The function of the old EGR valve is handled in another way.

 

I have a 90 and it doesnt have the HO 4.0. I think you mean 91-01

 

My bad, I swear it really depends on who I talk to as to whether the HO motors started in 90 or 91. Some guys claim to have HO motors in their 90s and others like you claim to not have the HO motor. I know my motor in my 91 is definitely an HO. I have had all too many dealings with the Renix motor in my son's 87. I have been learning the differences the long and painful way.

 

I think part of the confusion may stem from the fact Chrysler logos start appearing under the hood in 1990. The earlier Renix's I have own have none, where as the 90 I own has them all over.