To get the EGR working, follow this:
Please note that I have referenced the ECU pin numbers as the most commonly used convention followed by the Honda convention in parentheses i.e. A10 (A13).
First off, we will cover the control box that you will need to mount on the firewall – see the attached picture of the control box – there are four items in the box, the MAP sensor, purge cut-off solenoid valve, constant vacuum control (CVC) valve and the EGR control solenoid valve – the MAP and the purge are also on your Civic STD – you can use whichever of those that you want
on the right side of the picture you will see a bunch of circled numbers which are the vacuum lines – we will cover those later - you should have wires coming off the purge and EGR solenoid with a 4-wire connector on the end which plugs into the engine harness - wire colors on the 4-wire connector are BLACK/YELLOW, GREEN and RED – the engine harness will only have a 2-wire connector with BLACK/YELLOW and GREEN wires which connected to the purge – you will need to cut the 4-wire connector off your HF engine harness and splice it onto your STD engine harness, after cutting off the 2-wire connector – BLACK/YELLOW wires are always power – the GREEN wire is for the purge and the RED is for the EGR – when you splice the 4-wire connector on just match the wire colors, however, your engine harness won’t have anywhere to connect the RED wire on the 4-wire connector – you need to splice a new wire onto the RED wire and run it to ECU pin A10 (A13) - plug the 4-wire connector you installed into the 4-wire connector from the control box - that part of the wiring is now finished
now, we will move on to the EGR valve on the intake manifold – since you STD engine harness has no connector for the EGR valve, you will need to add wiring for it – the EGR valve has (3) wires, YELLOW/WHITE, GREEN/WHITE and YELLOW – the YELLOW/WHITE is for a 5 volt reference signal which is also used for other sensors like the TPS and ends up back at ECU pin C13 (C27), the GREEN/WHITE is ground which is also used for most of the engine sensors like the TPS, coolant temp and intake air and ends up back at ECU pin C12 (C26) – these wires can be spliced color for color into any of the wires to the other sensors – probably easiest to splice into the TPS wires somewhere back in the harness, not right at the TPS connector – for the YELLOW wire, you will need to add a new wire spliced onto the YELLOW and run it to ECU pin C8 – this should take care of all the rest of the wiring
now for the vacuum lines, see attached vacuum line diagram – the numbers on the vacuum lines match the numbers on the vacuum lines on the control box picture
this should be everything needed to get the EGR working properly.