EGR Delete

[dragstart]

I know I'm behind the curve on this, but I just got back into having a Fox after 25 years, and the two I had before were my wife's daily, so no mods.

I just got a '91 LX that has smog pump delete, no cats, BBK headers, and the egr tube going into the head is cut off and pinched closed. The EGR valve is still in place, has vacuum and is plugged in to harness connector. No dash warning lights or obvious effect on performance.

Here's why I'm asking advice. The car came with an uninstalled Edelbrock 3820 intake and I want to put it on just because.

I figured the smog equipment is already history, but didn't understand where I stood with the EGR valve and my searches didn't really help. Old threads, conflicting opinions, etc.

So here's what I'm asking.............is the EGR being hooked up still talking to the computer even though it is serving no function? Can I just unplug it and see if it throws a CEL light? Or is it already maybe deleted in the computer but never taken off? When I sorta figure out where I'm at, how do I move forward with the manifold install and deleting of the EGR?

TIA

 

[Bullitt347]

You can delete it with no issues.
The EGR is used to lower combustion temps in an effort to reduce NOX emissions.
It does not hurt HP/Trq because it is primarily used in part throttle operation.
It will not effect driveability or mpg in any real sense.
With the advent of VCT a lot of manufacturers were able to delete the EGR by having the VCT do essentially the same thing, but some have gone back to using it even on newer vehicles.

 

[dragstart]

You can delete it with no issues.
The EGR is used to lower combustion temps in an effort to reduce NOX emissions.
It does not hurt HP/Trq because it is primarily used in part throttle operation.
It will not effect driveability or mpg in any real sense.
With the advent of VCT a lot of manufacturers were able to delete the EGR by having the VCT do essentially the same thing, but some have gone back to using it even on newer vehicles.

Thanks. I assume the ecm makes adjustments based on what the egr is doing. Are there modifications that can be done to those old ecms?

 

[AeroCoupe]

Put a chip on them and dyno tune the car is about all that I know of. There are alternative ECU's that will plug into the factory harness but you get into having to have it tuned or learning to tune yourself (not a bad thing if you have that ability).

 

[Mustang5L5]

Really the best way to do it is to tune it out of the programming.

There use to be resistor plugs that will turn off the CEL and trigger an EGR closed state which sorta "tuned" it out, but those are no longer made. You can build your own using resistors. The diagram is readily available via google search

Honestly, it does nothing for performance to delete it. If it's there and functional just leave it alone. Down the road if you ever go with an aftermarket ECU which doesn't use an EGR, you can just install a block off plate and/or block it off at the heads or between the upper and lower.

 

[dragstart]

Really the best way to do it is to tune it out of the programming.

There use to be resistor plugs that will turn off the CEL and trigger an EGR closed state which sorta "tuned" it out, but those are no longer made. You can build your own using resistors. The diagram is readily available via google search

Honestly, it does nothing for performance to delete it. If it's there and functional just leave it alone. Down the road if you ever go with an aftermarket ECU which doesn't use an EGR, you can just install a block off plate and/or block it off at the heads or between the upper and lower.

It's not functional. P.O. somewhere up the line put on headers with no port. The EGR is still on with vacuum and electrical plug. No CEL, but haen't been able to check for 33 code yet.

 

[Mustang5L5]

To be honest, a CEL wouldn't be the worst of things. It will disable thee EGR function in the ECU and disable fuel injector shutoff on decel (which is a 93 cobra only thing).

Just have an annoying light to look at.

 

[TwoRockTwo]

The EGR is internal on the foxbody. It routes through the heads, up the center of the lower & upper intake and then into the egr spacer & valve.

What you’re describing on the back of the heads is part of the smog system that flows from the air pump through the TAB & TAD.

If you don’t have a CEL code on the EGR, it’s working as it should.