Intake Manifold Installation (01-05 Civic)
 

7th Generation Civic Intake Manifold Swap
Including fuel pump upgrade & return fuel line

Required Parts:
D16Y8 intake manifold (OEM or aftermarket – strongly discourage Skunk2)
Intake manifold gasket – 6th gen
Aftermarket intake – I used 99-00 Si Weapon R Secret Weapon
Adjustable Fuel Pressure Regulator – If using 7th gen rail need universal
Fuel Rail – You can use 7th gen rail and modify it… strongly suggest replacing, makes swap much easier
Fuel Rail bolts from 96-00 Civic (4-6) Trust me.
240cc saturated fuel injectors – Only if replacing fuel rail
Injector gaskets from earlier gen. Civic
SSB fuel lines – Get about 23 feet, one 10ft (this will be for return) and one 13ft no larger than -6AN. Get all required hose ends and fittings. (more on this later)
Fuel Pump – Make sure it is a High Pressure pump; recommend Walbro or Holley.
3’ 5/16th fuel line (rubber)
2’ 3/8th fuel line (rubber)
~ 16AWG wire in 3 different colors (red, black, and another)
3 8mm nuts
2 ½” length steel spacers

Additional Parts:
Fuel filter – made it easier to install fuel pump
Throttle body – I believe you can use your OEM TB.

WARNING!!!!!!
If you decide to use a Skunk2 intake manifold you will NOT, I repeat NOT be able to go back to stock without replacing the bolts screwed into the engine which the manifold sits on, also removal of a portion of firewall is necessary.

Preparation
If you do not already own one a Haynes or Chilton manual, buy one.
To bleed the fuel pressure remove the glove box and refer to the manual to see which relay to pull; on mine I only had two 1 blue, 1 brown; remove the relay(for me it was blue).
https://www.hondacivicforum.com/upfi...782865E863.jpg

Start the engine and allow it to run till it dies. Shut engine off. Disconnect negative battery terminal.

Tools:
Air compressor capable of operating a die-grinder
Die-grinder ($30 Husky from Walmart worked great)
Ratchet set (required metric sockets 8mm-14mm most commonly used)
Metric wrenches – 10-14mm
Tap and Die set (metric)

Step 1. Removal of OEM parts
I am not going to go into much detail, what I will say is that a Haynes or Chilton manual is a great tool.
• Remove air box or intake if you have an aftermarket one installed
• Remove accelerator cable from throttle body (also remove cruise cable if equipped)
• Unplug MAP sensor and mark sensor clip for identification later; pull sensor, set sensor aside
• Unplug TPS sensor and mark sensor clip for ident.
• Unplug EVAP sensor and mark clip for ident. Remove from TB and manifold.
https://www.hondacivicforum.com/upfi...01B9B18C5C.jpg

• Remove coolant bypass hoses from IACV on TB. (Shop towels or a rag underneath will help reduce coolant spill)
• Remove throttle body
• Remove PCV fresh air connector.
• Remove valve cover and remove nut on back of wiring cover connected to manifold.
https://www.hondacivicforum.com/upfi...0191172E43.jpg

• Remove throttle and cruise cable and cable holders.
• Remove Fuel line from fuel rail, simple squeeze and pull. (Check Haynes or Chilton for verification)
https://www.hondacivicforum.com/upfi...DD3E0510B5.jpg

• Remove EVAP line from pipe on fuel rail. (arrow in picture above shows EVAP line)
• Remove fuel rail bolts and fuel rail.
o Set fuel rail and injectors aside in a plastic bag.
• Remove all other hoses/sensors/etc (if any) from manifold.
• Jack car up for access to underneath bolts/nuts connecting manifold to head.
• Remove all bolts and nuts connecting manifold. (3 nuts, 2 bolts; bolts are at each end of manifold, nuts are 2 on top, 1 on bottom)
• Remove manifold.
• At this point I strongly urge those considering using Skunk2 manifold to think about how long they plan on keeping the vehicle and if you have a friendly mechanic and a welder. The next step will require you to trim your firewall and cut and re-thread the bolts from the engine head which the manifold sits on. If you are replacing the stock TB w/ the Skunk2 you will also need to make an “extender” in order for the TPS to fit. More about this later.

Step 2. Preparing Vehicle for Manifold
Ok I will do my best to recall and point out any and all issues I ran into later in the swap so you can be prepared and do them in this step.
• Let’s get into the cutting first, here is where your die-grinder and air compressor come in handy. I don’t have a picture but I will describe it in detail.
o You’ll need a cutting disc for your die-grinder and you’ll need to plug up the runners of the cylinder head w/ shop towel; I suggest not using thin paper towel as the die-grinder cutting produces heat.
o From the end of the threads closest to the engine, measure 1/8 inch and mark with a sharpie on all 3 bolts, cut at these lines.
o Once finished cutting all three bolts start with your 10mm die and begin to re-thread the bolt, the 10mm won’t do much but it will give you a guide to use on smaller dies. You should be able to turn the 10mm by hand. Start all three bolts or do one at a time which ever you are comfortable with. Next you will need a 1 inch socket and a ½ inch ratchet, I found it convenient to use a smaller socket to put inside the 1 inch to aid in keeping the threads straight, now place your 9mm die into the socket and begin to tighten and thread the bolts. Once you are done with the 9mm do the same with the 8mm die. You only need to thread a little more than half-way down the bolt. After all bolts are done replace the cutting disc on the die-grinder.
• Now we will trim the firewall. **NOTE: This is only necessary if using the Skunk2 manifold. If using OEM or short runner manifold skip this step and move on.
https://www.hondacivicforum.com/upfi...FCD4AA1AE3.jpg

o Remove the bolts and wire clips circled in yellow, cut along black line and underneath as far back as possible. The A/C line (thick alum. Pipe) may need to be moved out of the way, remove bolt and carefully bend alum. Piping as needed.
o Once finished trimming the firewall take a grinding stone and your die-grinder and smooth out the edges.
 NOTE**** This part of the firewall will be patched later.
• Now that all that is done we will move on to trimming the manifold itself so the bolts will line up properly.
https://www.hondacivicforum.com/upfi...A5EDC9855F.jpg
o I used a metal cutting rod that came with my die-grinder to widen the top bolt holes. I did nothing about the intake runners, I’m going to leave that for a port-match when I get a P&P done.
https://www.hondacivicforum.com/upfi...CD8B54FDFA.jpg
• That is the power steering fluid line, it needs to be moved a bit, the easiest way I found was to take circle 1 and bend it straight down then take the plastic to metal converter and bend it in the direction of the arrow. If you are a little sketchy about bending it DON’T, if you break it, it costs $120 from the dealership to replace. Circle 2 is the nut that keeps it connected, remove, allow to drain and then remove it from the power steering pump via two bolts (second image)
https://www.hondacivicforum.com/upfi...6642ADE6CB.jpg
o After getting the manifold in replace the line, this will make it much easier to bend into necessary shape, but takes some time since you will not have much room to work.
• Now the larger A/C line will also need to be moved, I found it easiest to just bend it upward, and let it sit just above the manifold(once the manifold is installed).
o Bef