D16A6 swap on an HF

[OBD1 Kenobi]

Please do this swap at your own risk, and I am not liable for any mishaps you have along your way. GOOD LUCK.

Ok, for me I started with my 1990 Rio Red CRX HF, and installed a 1989 CRX Si engine.
I bought the engine off of a fellow resource member, and rebuilt it.
Depending on the condition of the engine, you may want to do the same. This article will not cover rebuilding.

I am going to assume you have your engine/trans already assembled and ready to install.
First things first... a list of tools you should have.

1. 32mm 1/2" drive socket
2. 1/2" drive Breaker Bar
3. Pipe to fit over the breaker bar handle (cheater bar)
4. 1/2" drive ratchet
5. a decent array of 1/2" METRIC sockets
6. 3/8" drive ratchet
7. a decent array of 3/8" METRIC sockets
8. an engine hoist
9. I reccomend a Load Leveler for your engine hoist but is not required.
10. some chain to hook up to your engine.
11. I also recommend a few sets of pliers for removing hoses, etc.
12. a large hammer. I used a 3lb sledge
13. A decently large flat screwdriver, or some sort of prybar (for axle removal)
14. A CAN OR 2 OF P.B. BLASTER... THIS WILL HELP YOU A LOT!
15. A drill and a few drill bits.
16. An 8mm FLAT punch. (for the shift linkage pin)

After you have your tools ready, clean a space in your garage or wherever, and move your car into position. Break loose the Axle nuts. This could be tough, I drilled out the dented in part of each axle nut, then I sprayed each nut with PB Blaster, and let it soak for about 10 minutes. Then, using my 32mm socket, breaker bar and cheater bar, I stood on em and jumped until the nuts broke loose. Just leave em loose for now. Now is also a good time to break loose your lug nuts, using your breaker bar and 19mm socket.

Put the front end of your car on Jackstands, and remove the hood.
The hood is removed by the 4 screws on the brackets. Then carefully place it in a safe place to avoid scratches, dents, etc. Next remove the cables from the battery, and remove the battery. Also, as a start, spray all four of your engine mounts with P.B. Blaster.

Next, Drain all of your fluids, oil, transmission, and radiator. The radiator drain is easily accessible if you remove the plastic covers underneath the front of the car. There are like 4 or 5 plastic bolts and 1 or 2 metal ones, all of them 10mm.
The radiator drain plug is mounted sideways on the bottom of the right side of the radiator.

The transmission oil drain plug is on the bottom of the transmission, and is round and has a 3/8" hole in it to use your 3/8" ratchet to loosen that up.
Now for the engine oil drain plug: If you don't know how to drain your engine oil, I do not reccomend going any further on this swap.

Next thing is to un-do your lower Balljont.
Remove your wheels, and set them aside. Next remove the forks off of your front struts and set them aside. This is done with a 14mm bolt (on the top side of the fork) and a 17mm bolt (on the bottom of the fork) Next remove the cotter pin from the castle nut on the bottom side of the lower balljoint assembly. Then, using your 17mm socket remove the castle nut, and set it in a safe place. Do the same on the other side. Using your large hammer, give your lower control arm a few good whacks, until it pops off.

Good, next thing is the Axles.
you can take off your axle nuts now, and set them aside. You're wheel/hub assemblies should hang freely now, you can pull them off of the axles now. Next grab your big screwdriver or prybar, and crawl under your car, and using your prybar, pop the axles out of the tranny.
Set the axles aside, as you'll probably end up re-using them.

OK, while you're under there, remove the bolts/springs between the exhaust A-pipe and B-pipe and then remove your shift linkages. This is done with your BFH, and your 8mm punch for the shift linkage. Then there is one bolt holding the torque rod. This is pretty much it from under the car.

Next start removing your harness plugs, and radiator/heater hoses. Also remove your air intake assembly. Relieve fuel pressure (don't smoke!) by the 12mm service bolt on the fuel filter. Also remove the fuel line from the top of your fuel rail. Remove all of your grounds as well.. The one on the valve cover, and the one on the transmission.
Remove your clutch cable, your throttle cable, and speedometer cable (careful to not lose the speedo cable clip!)

If you have air conditionining, remove your compressor from the bracket (there are 4 12mm screws) don't worry you don't have to relieve pressure to remove the compressor. Tie the compressor to the front frame.

Remove your radiator, and set it in a safe place.
Coolant is going to spew, so have some towels handy.

Next remove Vacuum hoses, and any other hoses I may have forgot.
You're now ready to pull the motor.

Get your hoist put together, and positioned in front of your car. Using your load balancer or chain, and put a couple of 12mm bolts thru the chain and into the points on your motor:
refer to your helms manual.

Hook the balancer or chain onto the hook, and pull it until it's taut.
Now un-do your engine mounts, I also reccomend removing your battery tray.
Start pulling up slowly, the engine is gonna bind in a few spots, and keep cranking away, and be careful of bashing your master cylinder with your alternator.
That was probably the EASIEST part of the swap IMO.

Next, transfer anything else you may need from your old engine onto your new engine

One thing you DEFINITELY want to swap over, is you HF wiring harness...
Use the HF WIRING HARNESS I LEARNED THE HARD WAY!
DO NOT USE THE SI WIRING HARNESS!
You'll probably want to clean out your empty engine bay, and take a few pictures, just for
fun.

I'd call it a day, go take a shower, have a beer, and go to bed.

Day 2:
Good morning,
Lets get started...
Now you should have your motor, fully prepared, and ready to install..
Before going any further, remove your throttle body, cuz you'll be pretty sad if you end up SMASHING your Throttle Position Sensor.
We're gonna hook up our new engine to the hoist, and put it in.
Get your chains hooked up, and on the hoist and lift it up.
Move it over to the car, and be careful.
Now carefully finesse the engine into place, I dropped mine in tranny first, into the mount position, and stuck the bolt through - then I slowly got the other mounts lined up and stuck bolts through them, and finally torqued them all down.

Ok, you're motor is in!
Next I'd re-install your AC compressor (if you have one), then your radiator.
Put your throttle body back on and install your Throttle cable, then your clutch cable.
Hook your wiring harness into the chassis harness. and go to town reinstalling hoses, etc.
Re-install your Axles.
Fill up your tranny, (this can be done with a funnel and 3-4 feet of hose, I reccomend using Honda MTF. Fill up your engine with oil, and your radiator with 50/50 water/coolant - again I recommend using honda coolant.

Next comes your HF Black Box.
Pull of the cover of the Black box, and set it aside.
Next, remove all sensors except the MAP sensor, and the Purge Cutoff Solenoid. The wires for the sensor that's on the same plug as the MAP can be cut, I did it nice and clean, and popped the pins out of the plug using an AWL.

Then run vacuum from the map sensor to the designated spot on the Throttle Body. (red hose barb) and you can run vacuum into any other vacuum source on the I.M. (I just T'd into another source)
You're almost done... install your battery.

[OBD1 Kenobi]

Now for the ECU harness:


Now, for the ECU harness:

After you've installed the engine, you'll need to do some simple mods to get the ECU to work correctly. The are provided assuming you have no A/C, cruise, etc.

Get a manual, if you don't have one. If you don't, I'll explain this as "layman" as possible.

OK, on the Si ECU, there are 3 plugins for the wiring harness. Each one holds a different number of pins. 16, 18 and 20. From left to right, looking at the pins on the ECU, it goes 18, 20, 16. 18 is group A. 20 is Group B. 16 is Group C. The pins in each group are numbered left to right, top to bottom.

For instance, on group A, pin A1 is located in the upper left corner of the group. Pin A2 is below A1. A3 is to the right of A1, A4 is below A3 and to the right of A2. Drawing a picture helps you visualize this. it's the same on all 3 groups as far as the order of pins goes.

Get the bracket to hold the purge control solenoid and the MAP sensor installed, and use Si sensors, although the HF MAP seems to be identical (in terms of ID numbers). The wiring for those goes like this: Remove the EGR control Solenoid valve, the MAP sensor, and the Purge cutoff solenoid valve. They are all in the "black box" on the firewall. On the new sensor rack in the center of the firewall is the MAP and purge cutoff solenoid valve. Use the existing MAP sensor plug for the new MAP sensor. Probably will have to extend the wires. Operation of the MAP will be OK, as the Si and HF used the same routing and connections.

Using the new plug for the purge cutoff solenoid valve, route the green wire to the old green from the HF purge cutoff solenoid valve. The black goes to another black wire in the main harness in the fuse box, which is a ground. To reiterate, black goes to ground. MAP and purge cutoff are now done.

Next is the fast idle control solenoid valve (F-I-C-S-V), which is mounted on the back of the Si intake plenum, near the EACV. it's plug uses 2 wires: black/yellow and a blue. Black/Yellow (later referred to as B/Y) is a 12V + and routes to the B/Y from the EACV plug. The Blue wire goes to pin B2 on the ECU. B2 is currently connected to the green/yellow wire from the "shift up light" in the guage cluster. The plug for this wire contains a green/orange and a yel/red wire. It is under the driver's side of the dash, connected alongside the fusebox with a white plug. Cut the green/yellow wire from the plug on the harness and splice in the blue wire from the Fast idle control solenoid valve, with the new wire going toward the ECU. Don't connect the F-I-C-S-V wire to the plug under the dash, or weird stuff will happen with your shift light! The "shift up" light is now disconnected (YAAAAAA!!!) and the green/yellow wire on the plug under the dash now hangs bare. F-I-C-S-V wiring is now complete.

Next is a yellow wire in the 6-wire connector located next to the fuse box, and the large round and large rectangular connectors are on the same bracket. The yellow wire can be cut, and it routes from the "reverse switch". The switch just told the HF ECU when the car was in reverse. Nothing more. I do not recommend leaving this wire intact.

According to my diagrams (and a very in depth investigation in my car), the HF and Si distributors are interchangeable. They use identical harnesses, and all the wires eventually end up in the same place. On the HF harness, the white wire across from the vacant prong, on the 8-prong plug by the distributor (7 occupied prongs, 1 vacant) is routed completely different than the Si harness. The white wire DOES end up connected to the same pin on the ECU, so it's OK to leave everything on the distributor alone, whether you use an HF or Si dizzy. Si is recommended, though.

Now, unearth your ECU and break out the diagonal clippers. You will have to cut the following wires, as the HF ECU needed them, but the Si would probably get all confused if you used them. Cut the wire off from the plug at the ECU, and leave enough at the plug end, just in case you ever need to reconnect it.

Cut the red wire on pin A6. it is from the EGR Control Solenoid Valve. You probably already disabled it, but cut it here also, just to be safe.

Pin B2 is green/yellow and connects to the F-I-C-S-V, via your new wiring splices. It is no longer the "shift up" light trigger. Remember that. DO NOT CUT THIS WIRE.

Pin B7 told the HF ECU when the heater came on. Si does not use this pin, so CUT IT. Your heater should still work, as this wire was simply a 12V trigger to turn up the idle a bit. If the heater DOES NOT work after you cut this wire, reconnect it.

Pin B9 came from the reverse switch. This wire told the ECU when the car was in reverse. IT SHOULD BE CUT. If any adverse reactions occur with your car in reverse or if an ECU code pops up about it, reconnect the wire.

Pin B11 is from the Clutch switch. It told the ECU when the car was in reverse so it could lower the idle a bit. CUT THIS WIRE. If anything weird happens like an ECU code about the switch, reconnect this wire.

Pin C8 is from the EGR valve lift sensor. The Si doesn't even have one of those, so CUT THIS WIRE.

That's all the wiring mods you should have to do related to the PGM-FI.

All the wires I told you to cut are designated "HF-only" in the manual, and the Si sensor array never connects to them anywhere.

[mOONiLL]

On my ECU harness:

The A-13 and A-10 wires are Red.

The A6 is Green/Black. Should I still cut it.

edit (Nov 8, 2004):

My heater doesn't work, I'll try reconnectin the ecu wire.