EGR Options

[reddawn222]

I recently posted about whether or not to retain a functional EGR on my TBI conversion in order to meet emissions requirements (a new development for my county). Plasticboob convinced me I should have a functional EGR.

So, for all members who have converted to efi, how have you handled this?
Did you retain the stock vacuum/temp operated EGR or did you find one that can be controlled by the ECM that will also fit the stock mounting flange?

I did a search on this forum but did not find any answers.

Thanks.

[Billygoat]

I had the stock vac setup, but tuning was interesting since I was not sure what temp the cto opened and how the delay valve worked, so I got a the EGR control for the chevy system my (and most) TBI's are based on (89 350).
Ran a couple wires and a relay, and have the computer control it now.
I also rigger a temporary light in the cab to the relay so I can see when the EGR is on to help me tune.

If you are not going to tune yourself, you would probably be better off to stick with the factory cto/delay valve set up and let the computer "learn" how it works. Not ideal, and when you disconnect the battery it has to start over, but they truck will run fine, I ran that way for over a year.

[tgreese]

This is how Howell does it on their CARB-approved setup:



(scan courtesy of member thome).

[Billygoat]

Yeap, that is how I ran, and I reread the OP, the EGR valve itself does not change, just what operates it.
chevy uses

http://www.oreillyauto.com/site/c/detail/BWD0/EGR226.oap?year=1989&make=Chevrolet&model=K1500&vi=1050804&ck=Search_egr+vacuum+solenoid_02144_1050804_2077&keyword=egr+vacuum+solenoid&pt=02144&ppt=C0018

simple 1 line to mainfold vac, and the other to the egr.
you could wire 1 to a pos line and the other direct to computer pin #A4
or use A4 to control a relay (I prefer relay)
but you need to have to program set up to run it.
They one I started with was shut off and the XDF was missing the setting to turn it on.

If anyone wants to know, I can post what all settings I have and what they are set to - close to the ASDU bin, but not exact

[tgreese]

You should keep your catalytic convertor too.

[reddawn222]

Thanks for the replies. I have been staring at the stock unit and have not looked at how GM controlled their EGR. It sounds like I can use the Jeep/AMC EGR and adapt how GM controlled the vacuum signal to it with the ECM. I was thinking the ECM controlled the EGR directly based on engine temperature.

I have an EBL ECM so I will have to figure out how to set the necessary parameters when I get it all together.. I'm in the early stages of my conversion using a nice wiring harness I got from JeepsAndGuns.

Yes, I have a new catalytic converter.

[JeepsAndGuns]

I do not run egr on mine, and have not paid any attention to what the plug on the harnesses are connected to on the trucks I pull the harnesses from. But I think, its a electronicly controlled vaccume switch/valve. I think the ecm sends a signial to this valve, and it opens and sends vaccume to the egr valve to turn it on.
But do not quote me on this.

[FSJ Guy]

I do not run egr on mine, and have not paid any attention to what the plug on the harnesses are connected to on the trucks I pull the harnesses from. But I think, its a electronicly controlled vaccume switch/valve. I think the ecm sends a signial to this valve, and it opens and sends vaccume to the egr valve to turn it on.
But do not quote me on this.

This is my understanding, too.

When I added my VSS, (Vehicle Speed Sensor), I had to disable the EGR function so it wouldn't throw a trouble code. I disabled the EGR by setting the EGR minimum temp and speed to the maximum values.

If I get an EGR equipped manifold, I may try to use the EGR again.

[Billygoat]

I do not run egr on mine, and have not paid any attention to what the plug on the harnesses are connected to on the trucks I pull the harnesses from. But I think, its a electronicly controlled vaccume switch/valve. I think the ecm sends a signial to this valve, and it opens and sends vaccume to the egr valve to turn it on.
But do not quote me on this.

see my post 5 back