Does EGR valve matter?
 

I just noticed that along with my VTEC-E swap into my '95 Civic CX they put a cover over the EGR valve, (blanked it off), and there is no box with the solenoid and vacuum control valve, does it matter? I've also got a P08 ECU, non-stock exhaust manifold (4 into 2), with 4 wire 02 sensor. Power seems good, idle is 750 rpm (a little fluctuation), but mpg is terrible, definitely worse than the original 16 valve Canadian CX engine. I just got a P07 ECU and I'm going to get a 5 wire 02 sensor, hopefully with the stock manifold, does the EGR valve matter?

Re: Does EGR valve matter?
 

Exhaust Gas Recirculation is mostly for NOx emissions control. However, EGR at part load improves fuel economy because it reduces manifold vacuum and associated throttling losses.

Re: Does EGR valve matter?
 

If you're missing any emission control systems in that car, the mileage will definitely suffer. Ask them why they removed that part and perhaps ask them to put it back since it's necessary to pass emissions.. How about a link to the company that did the install?

Re: Does EGR valve matter?
 

Not to mention, depending upon where you live, you may not even be able to register the car if you have periodic inspections which include emissions testing.

Re: Does EGR valve matter?
 

In my Civic, EGR is also used to control knocking, as it brings combustion temperature down.
This appart from the already mentioned NOx decrease.
So, yes, EGR matters.

Re: Does EGR valve matter?
 

Ok EGR matters, I'll put one back on.
I don't have a link to the shop that did the swap but their name is "Optional Performance" in Toronto, Canada.

Re: Does EGR valve matter?
 

EGR is purely an emissions control device and a bad one at that. Of 3 cars that I've tried disabling EGR, all 3 have gained MPGs in the process. Some cars have a temperature sensor in the EGR pipe that will register a fault if the pipe doesn't heat up periodically. You will need EGR to pass emissions test.

Re: Does EGR valve matter?
 

Thanks for that (tjts1), because I'm going to have enough trouble finding a VX exhaust manifold, or modifying a regular 4 into 1 (putting the O2 sensor in the central hotspot and maybe wrapping it for extra heat), then wire up the P07 ECU and the 5 wire sensor, into my '95 CX harness, so it's nice not to worry about an extra thing!;)

Re: Does EGR valve matter?
 

that's nice that the guy thinks that but the VX is a very different car and in fact uses the EGR when doing it's MPG thing thanks to its lean-burn function. If you want lean burn to work, EGR MUST be working. There is a reason why the VX has an EGR but none of the other civics have one. In other words, only the LEAN BURN CIVICS HAVE AN EGR.

Re: Does EGR valve matter?
 

And that reason is that lean AFR causes much higher NOx emissions. The EGR is necessary for the car to have any chance of meeting an emission standard.
https://www.planetcampbell.us/AFR_Emissions_Graph.jpg