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If any of these pictures dont load right click on them and hit "show picture" they are all there, but since they are large they might not load correctly the first time, especially on a slow connection.

WARNING: This was done on a OBD2a car so I do not claim to be 100% accurate on the OBD2b stuff. But it should work just fine.

I recently did a mini-me swap from y7 to y8 in my 1998 DX daily, and there is a ton of misinformation floating around on this. Since this seems to come up fairly often I decided to do this writeup so I could refer people back to it. Most guides are based on switching to OBD1. This guide was written with staying OBD2 in mind. It was written to keep your stock wiring harness. I dont know why it seems so many people want to switch wiring harnesses, it is harder and more expensive. If you can install a car radio you can handle the wiring involved here. If you have trouble with soldering/heat shrinking, invest in some flux, decent solder and get one of these: Weller Self-igniting Cordless Butane Solder Kit I have had mine for years and I love it.

Shopping list:

- 2+ ECU pins (you only need 2 but more are handy in case one gets messed up).

- 3 2 wire Honda plugs. One for the Vtec pressure switch, one for the IACV, and one for the knock sensor (it is 1 wire but the 2 wire plug fits perfectly, just remove the extra wire)

-A 1 wire female vtec solenoid plug, or an aftermarket single wire plug pair. Insulated spade connectors will do.

- A knock sensor. If you bought a whole d16y8 engine it should have one, if you are just switching the head, you need to get one. I suggest either putting it in before the head or intake goes on (whichever is last. Otherwise it is a bitch to get to. But be careful not to break it off!

- At least 12 feet of decent automotive grade black wire (12-14 gauge) 20 feet would be better for those of you who are worried about having to make extra splices, or if you want to do extra special fancy routing.

- A ECU that matches your year range and tranny type. OBD2a is 1996-1998, OD2b is 1998-2001. Automatics use a 3 wire IACV mounted to the throttlebody. Everything else uses a 2 wire IACV attached to the back of the intake manifold.

- 1/8" heatshrink, or a variety pack.

- Electrical tape, or other wiring wrapping solution.

- Oil change stuff (if you get antifreeze in your oil, change it ASAP, dont drive the car, just change it)

- Antifreeze.

- For the mini-me I found 3-4 feet of 3/8" automotive grade hose handy. The matching hose clamps might be useful as well.

- Any other standard tuneup type stuff you want to change. IE cam belt, water pump, plugs/wires/cap/roter etc. Its up to you.

THE INTAKE MANIFOLD
Make sure to get a intake manifold that has the correct IACV to match your ECU type. If you have an auto tranny, get one with a 3 wire IACV off a automatic EX. Otherwise get one with a 2 wire IACV. Also OBD2b intakes have cold start assist ports. If you are using one of these in a OBD2a car you need to seal those. I sealed around them then plugged the top port.


Auto manifold is the top one (3 wire IACV on throttlebody), The bottom one is a manual style, this one happens to be a Z6 intake, but the setup for the IACV is the same as a manual y8 intake manifold (the 2 wire IACV goes over the 2 holes you are looking at).



If you get a manifold like this one, seal around the cold start assist ports and seal the nipple coming right up out of the flange.

INTAKE AIR PIPING
The EX has a 3"+ hole that the stock intake air piping goes through. The other chassis types are missing this hole. So you either have to adapt a DX style intake/CAI to attach to the y8 intake manifold, or you have to drill a 3"+ (or whatever size your piping is) hole in the area behind the drivers side headlight if you want to use a stock EX airbox or EX style CAI.

THE SWAP
First off, swap the head/engine. I am not gonna get into the mechanical portion, its a straight bolt in swap and there is tons of writeups on how to change a head. If all else fails read the manual. After the engine is in, plug in everything. You might have to unwrap/rewrap a couple wires but none of the common plugs between the y7 and y8 will have to be extended, they will all reach.

If you are worried about the wiring and downtime, you can throw the d16y7 throttlebody (you will probably have to switch throttle plates) and injectors onto the d16y8, and then run the d16y8 on the stock DX ECU (the P2E) It will basically run like a DX engine (no vtec), it might throw a rich/lean code or something, but it will be perfectly drivable until you get a chance to do the wiring.

ENGINE BAY WIRING
Pull out the battery, battery tray and support underneth. You will see a plug that the main engine wiring harness goes through. Unbolt it (2 10mm bolts) and run 2 black wires (black is low visibility) through it, label both ends of one wire "vtec" and both ends of the other wire "oil pressure" (if you have an automatic route 3 wires and run one to the knock sensor). Leave enough wire to get to the ECU, 2 feet should do it, but leave 3 if you are extra cautious.

Next route the engine bay side of those 2 wires to the Vtec solenoid area. You can use zip ties to attach the wires to the loom, or unwrap the whole thing and re-wrap it with them inside it. That is up to you. However I used black wires so I could run them outside the loom.


Attach the wire labeled "oil pressure" to the the red/yellow wire coming out of the 2 wire plug. The green wire coming out of the 2 wire plug goes to chassis ground (I put an eye on it and it went under one of the bolts that holds on the solenoid). Then attach the "vtec" wire to the single green/black wire coming out of the Vtec solenoid. Depending on your 2 wire plug these colors may differ, but you should be able to tell their locations with this picture.

Do the 2 wire conversion on the IACV (unless you have an automatic), this is covered in depth other areas or in the pictures at the bottom of this thread. However instead of Instead of throwing out the 3rd (orange) wire extend it to go to the knock sensor on the back of the engine. It is already pretty close.

Screw in the knock sensor (I suggest doing this before you put on the intake). Using one of your 2 wire plugs, figure out which wire is not used and remove it. Then attach the wire remaining in the plug to the wire you extended from the IACV (the orange wire).

(this is a B-series knock sensor, but it looks the same, and is in about the same spot on a D-series)


OBD2a ECU WIRING (OBD2B is below)

Now, inside the car, route your 2 wires to the ECU. If you have not already done so, do the ECU side of the 2 wire IACV conversion. Take the extra orange wire (that you extended to the knock sensor) and plug it into D6. Attach pins to your 2 black wires and plug the "oil pressure" wire into C15, and your "vtec wire" into A8. Refer to the picture below for plug locations. Plug in your new P2P ECU and enjoy your swap!



OBD2b ECU WIRING

Now, inside the car, route your 2 wires to the ECU. If you have not already done so, do the ECU side of the 2 wire IACV conversion. Take the extra orange wire (that you extended to the knock sensor) and plug it into C3. Attach pins to your 2 black wires and plug the "oil pressure" wire into C10, and your "vtec wire" into B12. Refer to the picture below for plug locations. Plug in your new P2P ECU and enjoy your swap!

 

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Great write up. I'll have to consider this as I'm looking for another y7 motor but it seems they are nowhere to be found. But y8's seems to be everywhere. RodKnock sucks.
 

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This is the best write thus far. It gives you step by step guide.
Please pay real close attention to the intake manifold or your car might not start .
 

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d16y8 knock sensor

Ok so I know its been a while since this thread started but I need help with the crank sensor, I'm not sure where u connect the two wire connector to it? Or if I'm looking at the right wire?? Some pics would really help if anyone has any.
 

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Very good writeup :TU:

When I swapped my blown y7 for a y8 I failed to realize how important obd2a vs obd2b is when i comes to the cabin harness. I had a '00 engine in a '98 car, so my speedo and tach didn't work and I had a couple other smaller issues too. After changing the engine harness to an obd2a one everything worked well (for a while lol).

rep'ed
 

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hey i just did this swap (98 d16y8-99 car) and i did everything as you said. (your a genius by the way) but im havin issues. i've got codes p0141 p1509 and p0113 showin up. when i start my car she orignally idles at 300-400 rpm and when she warms up she get up to 750. however if you press and hold the gas till bout 1500 rpm the idle starts to bounce like a vacume seal leak.. now im totally lost on how to fix this.. fyi she has no cat an d im expecting that code to pop up..and the knock sensor broke but the code is not showing up for that either..if ne one can help it will be greatly appreciated
 

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I know this is an old post but thank you all for the help listed in it. I purchased a 96 ek hatch in 04 as as theft recovery. Had to change bearings and car ran fine. After sitting for 9 years motor started to knock again. Purchased two motors from local junk yards and both knocked worst than the original. Think i have a lead on a d16y8 for cheap and this post will help with swap a IM SURE.
 

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Hi im mid way through this conversion on a uk d16y7 which has only 1 o2 sensor. Im doing the wiring at the minute and ive just plugged the ecu in and switched on ignition. Im getting only 1 error code 63- secondary o2 fault. Now what i dont understand is the uk y8s dont have secondary o2 and im not getting a code for primary o2 which isnt plugged in anyway?
 
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