DOHC ZC swap

If you have labeled all the vacuum lines, fuel lines, wires, and pretty much anything else that connects to the engine or transmission, then the ZC engine should be very easy to install. 

While the engine is out do all the necessary things to it that otherwise would be a pain in the ass. I highly recommend replacing the timing belt, alternator belt, oil filter, fuel filter, fuel injectors, clutch, radiator hoses, water pump, spark plugs, and if money permits, anything else you can think of that could possible break at a later time. All of these can be done while the engine is in the car, but while everything is apart it is a good idea to do it all at that time. 
Almost every engine that comes over from Japan has a broken TPS (Throttle Position Sensor). You can either use the old Si TPS, or you can replace throttle bodies entirely, they are identical. 

Mount the old Si motor mounts on the ZC engine and transmission before dropping her on in. If you are in need of new motor mounts 1988-1991 Si mounts are identical and will work perfectly. 

At this time or at any time I would recommend removing the old ECU from under the passenger side floor and plug in the new ECU in. If you did not purchase a new ECU skip this step. The Si ECU will work, and the car will run, but the 1988-1989 Integra ECU will give you lots of noticeable performance, which is what I used. My 1989 Teg ECU cost me used at a local junk yard.

Now you should be about ready to drop the ZC in. Make sure you raise the engine up enough so that it clears the front bumper and radiator support. The more people you have the easier it is to drop it in. I did it all by myself so it can be done with a little patience. While lowering it in you have to do a lot of wiggling for it to go into place correctly.

It is time to start bolting her back in. Bolt the rear motor mount in first. Then the right mount, left mount, and front mount. Make sure you have a torque wrench and torque everything down to spec. 

At this time you can remove the chains and the lift should no longer be needed. The shift linkage and torque rod can bolt on next. The Shift linkage roller pin needs a little physical influence to go in, then the clip and the rubber boot will go on over that. The torque rod bolts right up along side the shift linkage. 

Next comes the axles they can be kind of a pain in the ass, just don’t bash on them. I ordered mine from PlaceRacing. Brand new ZC axles, and they fit perfectly. First, unbolt, and swing out the hub assembly. Slow and gently slide the axle into the transmission. Make sure the axle clicks in. If in properly, you should be able to pull on it without it coming out. Now gently put the other end of the axle in the hub and bolt the hub back up. Put the large nut on and make sure it is really tightened down and that the part that bends in, gets bent in, you’ll see what I am talking about when you are doing it. On the right side you need to do exactly the same except you need to install the intermediate shaft. The intermediate shaft bolts up to the block, and you may need to go to NAPA or some hardware store and get the 3 bolts for it. The axle slides right into the intermediate shaft and the rest of the install is the same as the other side described above. They use an intermediate shaft to reduce torque steer, and the intermediate shaft makes it a hell of a lot stronger. 

Now comes the easy part. Match up all the vacuum lines, plugs, and wires, that were labeled previously, it should be very easy and self explanatory. There Is one vacuum line in the very back top center, that has no where to go. You can either plug it up, or you can get a T connector and splice it into one of the vacuum lines on the intake manifold. 

On my car I had to do a little basic wiring. On the Si distributor there is a 7 wire plug on the wiring harness, but only 5 plug connector on the ZC distributor, and there is a sensor on the exhaust cam, which is the cam angle sensor, that has no where to plug into. So this is what you do: 

1.The Civic wiring on the distributor has an 8 pin connector and a 2 pin connector. The 2 pin connector from the Civic wiring harness will connect to the ZC disributor.

2. Pop out the 8 pin connector off the Civic engine wiring harness

3.This will expose 7 wires.

White/thin

White/thin

Orange

Orange/Blue stripe

White/Blue stripe

Blue/Yellow stripe

Blue/Green stripe

4. Pop the pins out of the square ZC plug, This will expose 5 wires.

White/Thick

White/Thin

Orange

Orange/Blue stripe

White/Blue stripe

5.Now you simply place the five pins in the square harness and get rid of the round Civic one. 

6.You now have two extra wires which are Blue/Yellow and Blue/Green

7. These two wires go to the green plug on the crank angle sensor which comes off the exhaust cam. You’ll need to splice the wires, but make sure to use bullet connectors. If you don’t you will lose to much power through the connection and the computer may throw a code. 

The only problem is that you change the cylinder position sensor and that may cause you to throw cylinder position code. Which happened to me, so I disconnected the check engine light cause its annoying to have on all the time. But it will not have any effect on the way the engine runs.

Now it is time to hook up all the radiator hoses, and drop in and bolt back on the radiator. Don’t forget the plug that goes into the radiator fan. Fill it with coolant and check for any leaks. 
Adjust the clutch cable to the appropriate tension or clutch release point you prefer. Also adjust the throttle cable to an appropriate tension. 
Connect all the battery connections to the starter and fuse box. Make sure all grounds are connected, and don’t forget the valve cover ground or else it wont turn over. 

Put the intake on and the breather that goes into the intake, clamp intake pipe firmly to the throttle body.

Now would be a good time to fill the transmission oil. I highly recommend using fully synthetic oil in it. Snake a hose from the oil to the oil fill plug and fill it with oil till it comes out the fill plug. 

Fill the engine with engine oil too. I also recommend fully synthetic oil. 

Make sure the lug nuts on the wheels are on tight, and look over the engine a few times and look for anything you may have missed. If you take your time you should not be missing anything. 

Take the car off the jack stands and get all pumped up to start the beast. 

Hop on in the car, push in the clutch and turn that key. If you did everything right it should start right up. Waite about 20-30 minutes at idle, then it should be safe to take her for a spin. 

Dual Point to Multi fuel injection

DPFI-MPFI There are two major wiring changes that you'll have to do going from a DPFI system to an MPFI and a couple other minor things that need to be done too. The first one is the crank angle sensor wiring which is the easy part. The second one is the fuel injector wiring which is slightly more complicated. Also, you'll have to switch the two wires on the TPS because the TPS on the new intake works in the opposite direction. If you dont switch them, the ECU will think that the engine is at Wide open throttle when its actually at idle. I highly recommend soldering and heat shrinking any electrical connections you will be making because it is very possible for connectors to come loose from all the vibration and solder will hold up better in the long run. Also, the TPS and EACV plugs are too short and they'll have to be extended. You're also going to have to switch the manifold support bracket, since the bolt parrern from the support to manifold is different from DX to SI, although they still bolt up on the block the same. TO HOOK UP THE MULTI-POINT CRANK ANGLE SENSOR:
- First, you'll have to go to the passengers foot well to where the ecu is located.
- Pin B10 and B12 should both be empty.
- You'll have to cut and move the wire that goes to pin C1(orange) over to pin B10, and move the wire from pin C2(white) over to pin B12. Don't get these two mixed up or else the ignition timing will be severly retarded. Leave enough wire at the ECU side of pin C1 and C2 for next step.
- Now run wires from pins C1 and C2 into the engine compartment and label them.
- There will be a connector on the new Si distributor with two unused pins. One of the wires will be blue/green stripe, and the other will be blue/yellow stripe.
- The wire that is blue/green stripe will go to the wire from pin C1 on the ECU and the other wire that is blue/yellow stripe will go to the wire from pin C2.

SWITCHING THE WIRES AT THE TPS:
This pretty much explains itself, just switch the two outside wires(green/white and yellow/white) around at the TPS and then you're done this step. I used the TPS connector off the Si harness, just so that I could just match up all the wires, since the wires are already reversed on it.
INJECTOR WIRING
(In the car):
First of all, while you're still in the passengers footwell, cut wires A3(yellow) and A7(red), although leave some wire on the ECU side for later use. Now run wires from pins A3 and A7 into the engine compartment and label them.
(Engine Compartment):
- Mount the injector resistor box up on the drivers side shock tower.
- Connect the yellow/black wires from the two DPFI injector harnesses and run it to the yellow/black wire on the injector resistor box.
- Connect the yellow wire from the DX injector to the #1 injector (brown wire).
- Connect the red wire from the DX injector and run it to the #3 injector (blue wire).
- Connect the wire you labelled A3 to the #2 injector (red wire).
- Connect the wire labelled A7 to the #4 injector (yellow wire).
- Then, connect the 4 red/black wires coming from injector resistor box to each of the four injectors.