NHB

Looking for someone to check my notes on upcoming swap. I got my hands on an EK for cheap: 96 EX Coupe A/T with a toasted D16y8 motor. I'm going to be dropping in a D16y7 long block, pulled from--I believe--a 97 or 98 M/T hatch that had a GSR motor put in. I've spent the last week scouring forums for any potential issues that might arise, but wanted to check here before turning any wrenches. So far I have not found anything in the archives relating to this identical situation.

As far as choosing to go with the non-VTEC y7, the main rational here was cost and labor. I toyed with the idea of hunting down a z6 or y8 head, but I'm not really interested in running oil lines to enable VTEC or doing any mini-me stuff. This EK is going to be for my gf who doesn't know how to take care of a clutch, and doesn't need VTEC anyways. (although she vehemently disagrees--yeah, what a jerk I am eh? ) I've only got a few free weekends to do this, so I figured the quickest fix would be to rip out the bad y8 head/block, drop in the y7, and throw on the A/T.

Anyways, here's what I've gathered so far, I think most of it is reliable:

1-ECU- People have told me the Auto y8 and y7 ECU's will both work with either motor (depending on your definition of 'work'). At first I thought I could just de-pin VTEC and live w/ the CEL codes....but after searching here I think the best bet would be to track down a y7 OBD2a Auto ECU and use it w/ my y8 VTEC harness: (I'm not getting an ECU with my donor motor because it's an M/T version)

from https://honda-tech.com/zerothread?id=1321618
"Blew my y8, dropped in a y7...now car doesn't rev past 5500 and kinda bogs every now and then. Everyone says its theECu since Im using the y8 vtec one. would the y7 non vtec ECU plug in and work?"

Reply: "use the y7 ecu. you will stop throwing codes and it will work 100% better. the ecu is still looking for vtec/oil pressure."

I'll admit I have not studied the pinout diagrams in detail yet, but will I want to simply de-pin the VTEC wiring from the EX harness before plugging and playing a y7 ECU?

2-Intake Manifold- Planning to re-use the y8 IM w/ a new y8 IM gasket. I understand everything should bolt to the y7 head no problem, but considering I'm looking to grab a y7 ECU, I'm a little confused on this IACV issue:

from https://honda-tech.com/zerothread?id=1863277
"the Y8 engine use a 2-wire IACV whereas your Y7 engine uses a 3-wire IAC. The Y7 ecu looks for a 3-wire IACV. So if you try using your DX ecu on a Y8 engine, you're going to get a check engine light for the IACV because the Y8 doesnt use a 3-wire IACV. BTW, the IACV on a Y7 engine is integrated on the throttlebody; the Y8 IACV is seperate and located on the backside of the intake manifold. Altho, an AUTO Y8 intake manifold uses a 3-wire IACV!"

Assuming that final little note about the y8 Auto intake manifold is accurate, I should not have to do any re-wiring of the IACV system, correct? I'll have a y7 ECU on an EX harness looking for a 3-pin IACV, which luckily, I'll already have since the old IM from the blown motor is an Auto y8 version. ?

3 - Exhaust Manifold - Ok I'm clear on the fact that the catalytic conv. is in different spots when comparing the y7 and y8. I want to re-use the y8 stuff from the exhaust mani down.

from https://honda-tech.com/zerothread?id=1899164
"on the d16y8, the secondary o2 is under the driver, INSIDE THE CATALYTIC CONVERTER

on the d16y7, the secondary o2 is in front of the block, INSIDE THE CATALYTIC CONVERTER WHICH IS RIGHT THERE WHEN YOU OPEN THE HOOD"

As far as extending the secondary 02, would the best bet be to simply grab some lengths of wire from a pull-apart junkyard? I read somewhere that these 02 wires are all shielded; if you don't use the right gauge to extend them you can end up with faulty/incorrect readings being sent to the ECU. I'm assuming here that both engine types are using 2-wire 02 sensors?

I'm also having trouble tracking down a thread I saw in regards to what gasket is preferred for y7 head and y8 EM combo. Saw the answer but forgot, I think it said to use a y7 gasket.

4 -Dizzy- I can't find the links now, but I saw several posts suggesting that the y7 and y8 dizzy's are totally interchangeable. This surprised me: a dizzy wired for VTEC will work on a y7 without throwing codes? I don't doubt the guy knew his stuff, but it still seemed odd... I will have one of each kind, but the kid I'm getting the LB from mentioned his y7 dizzy had been starting to act up; if I can I'll re-use the y8.

5 -Auto Trans- I've never really messed with yanking a honda auto trans before. I'm assuming, since it's all D-series, that this will be a relatively simple operation of transferring everything off my blown y8 onto the y7 block and then slapping the transmission in? The donor motor is having the M/T trans pulled this week, so I should be picking it up with a bare flywheel. If anyone knows of any issues I may run into installing this stuff onto the formerly M/T y7 block, plz give me a heads up!

On a side note, while trying to backread some of the Auto to M/T FAQ's in the 'Helpful' sticky thread, the following is mislinked, goes to some post about an ITR getting jacked:

https://honda-tech.com/zerothread?id=1377459- EK Auto to Manual Swap


Well, that's about it for my long winded *expletive* post. Thanks in advance to anyone who can answer some of these questions, or confirm the info I've found.

Oh and if this post should have gone to Tech/Misc section, sorry...I wasn't certain which area was more appropriate.

Soichiro's way@MF

1) You should not have to de-pin anything when using a y7 ecu on your vtec harness.
2) Correct, 3 wire plug n play.
3) Your Y8 exhaust manifold should bolt right up to your Y7 longblock so you can use your existing HO2 S1 & S2. BTW, These are both four wire "Heated" sensors- OBDII yo!
4) Good plan
5) You should not have any troubles with the A/T swap. Since you are using your original TB, you'll have the A/T pressure cable- needed to bolt everything right up. You will have a few connectors left unused from your Y8 harness. KS, vtec PS, etc.

Make it so.

NHB

You make Soichiro proud, many thanks.

Presidential_Detail

I have used the y8 ecu on my y7 and it ran betetr than any other vtec motor ive ever had. Im actually thinking about taking my y8 head off in favor of my y7 head. You will just throw a code, but it will still rev normally to the redline.

ifIexplode

I have a Y7 auto ECU out of a 98 ej6 if you need it. OBD2a

NHB

IfIexplode, thanks for the heads up. What is the P2E code on that ECU you have? I recently went to the Canuck pull apart yards and found an ECU in what I believe was the corpse of a 96-98 4dr LX. The code has thrown me off though:

37820-P2E-C81

I found this list helpful, but not complete for Canuck stuff:

"96-00 ECUs (P2E, P2P, P2J, P72)
5spd = 000, 001, 002, 003, A00, A01, A03, C00, C01, C02, C03, J00, J01, J02, A11, C11
Auto = A70, A71, A72, A91, A92, C70, C71, C72, C91, C92"

From what I understand, LX, DX and CX from 96-98 all had the non-VTEC motor, so I'm thinking this C81 may work for what I need with my y7. Do you know if Canuck civics have thier own unique ECU designations?

Thanks.

ifIexplode

Im not one to be an ECU guru.
But the code on the y7 ECU i have is:

37820-P2E-L82

I had this y7 computer running the Y8 motor i swapped into my car and it ran like **** until i got a Y8 computer.

I had this bookmarked.

http://www.hondata.com/techecuid.html

Presidential_Detail

Maybe running the y8 off of the y7 ECU will run like ****, but ive had great succes running my y7 off a y8 ECU. just throws a VTEC CEL. But it was still real fast.