MayDay!! - Hard Accel Killed Idle

[89 MJ]

52 minutes ago, AnotherOldJeepGuy said:

What is the downside to removing the EGR?  Doesn't this mess with the ECU?

People that have to experience emissions testing will not pass without EGR. If you do not have to go through any sort of emissions testing/inspection, there is no downside to deleting it that I have heard. All it does is feed your engine's waste right back through it, reducing efficiency. 

[AnotherOldJeepGuy]

OK got it.

 

Does anyone know of an EGR Delete Kit?  

[Eagle_SX4]

31 minutes ago, AnotherOldJeepGuy said:

Does anyone know of an EGR Delete Kit?  

@boxyjeep sells ones.

https://boxyjeep.com/products/jeep-cherokee-4-0l-egr-plate-1987-1990

 

[AnotherOldJeepGuy]

Great!  If I decided to go this route I'll definitely give boxyjeep the order.

[Gojira94]

1 hour ago, 89 MJ said:

All it does is feed your engine's waste right back through it, reducing efficiency

 

Totally agree with getting rid of the EGR if your state won't ding you for it. Surprisingly, the siphoned exhaust gasses help reduce combustion temps. Two benefits - reduce chances of pre-ignition/ detonation from elevated combustion temps and reduce oxides of Nitrogen (NOx). High NOx is what fails emissions when EGR is deleted or not working properly. Most people don't like the idea of the buildup of combustion by-product in parts of the 'clean' intake side of the engine.

[AnotherOldJeepGuy]

Here in TX emission testing is no longer required for vehicles over 25.  (IIRC I think there are a few TX cities that do require it but not where I live). [Oddly enough the state still collects the same annual fee, just discontinued the test, way to go politicians]

 

I'm not sure I fully understand that last part, "Most people don't like the idea of the buildup of combustion by-product in parts of the 'clean' intake side of the engine", is that a Pro or Con to EGR Delete, sounds like it's a Con?

[Gojira94]

2 hours ago, AnotherOldJeepGuy said:

that last part, "Most people don't like the idea of the buildup of combustion by-product

 

A bit of exhaust is siphoned into the intake manifold upstream of the injectors. There tends to be a gummy/ sooty buildup of stuff that would normally be going out the tailpipe in the EGR valve and in the intake where it's attached. We normally would picture nothing but clean filtered air and fuel going in the intake...

 

Reduction of combustion temps via EGR matters the most for newer generation engines with relatively high compression that depend on EGR for:

1. using all the timing it's calibrated for to produce/ maintain rated power/ torque levels (reduced temps/knock retard)
2. to minimize NOx to meet emissions standards

For an old engine design essentially from the end of the 50s, with 8.8:1 static compression, that runs on low octane fuels, EGR isn't doing a lot for it.