Wrench6

I swapped a 1997 Civic EX Manual Transmission D16Y8 VTEC with a D15B Non-VTEC.

I used my Intake manifold and my alternator and I put a new D16Y8 type distributor back on the engine. I also put the CKP from the Y8 onto the B engine in order to facilitate the wiring harness.

I am currently using the D16Y8 ECU and harness and as I'm sure that you know, the engine runs and idles with no issues; aside from low power output in the 2500RPM range and doesn't really come into the proper torque curve until I'm into the 3500RPM range. I'm simply tired of downshifting and high revs at low gears.

The D15B has a P2A-9 head with a 97 stamp.

The D16Y8 ECU is a P2P-A32 OBD 2

The D15B requires a P2C/P2E ECU

I have the opportunity to get a P2E-C01 OBD 2 ECU at a decent price.

My only questions are: Can I use the D16Y8 harness? If I can use my existing harness, is there an adapter required to marry my harness to the P2E ECU?


If I do need to get a new harness for the P2E ECU, all I have found are B15B7 harnesses available; will it work with my D15B engine?

I appreciate any and all help that you guys can provide. I've collected a trove of information and specs from here and other areas of the Interwebz and am grateful for all your input

NotARaCist

iTrader: (1)

As long as the OBD variants are the same (96-98 is OBD2A, 99-00 is OBD2B in the US, but I don't know about foreign markets) you'll be able to use the same harness. If something is different, but it's still an OBD-standard, you can get adapter harnesses.

Wrench6

Thanks. Sorry about the previous thread hijack. Many forums that I've been/belonged to would prefer the same issue being addressed in one thread if possible, as it keeps like issues together. Especially when the issues are so similar. I'll get the new ECU and go from there.

ETA: There shouldn't be any reason that I would need to reprogram the P2E ECU, is there?

Wrench6

Here's something that I have been curious about...

Will it change anything in the way that the engine responds if I completely disconnect the VTEC wiring from the P2P-A32 ECU, so that it doesn't read the connection?

Mind you, I'm going to get the P2E-C01 ECU and replace the P2P-A32. I was just curious if that will have any effect on the performance of the engine.

Also, I'll ask again: Will I need to reprogram the P2E-C021 OBD2 ECU when I get it, or is it simply plug-and-play on an OBD2-OBD2 swap?

Thanks

eghatch9295

iTrader: (1)

https://www.hondata.com/techecuid.html you should currently be obd2-a. if the p2e is obd2-a, it is plug and play with your current harness. if it is obd2-b, youll need a jumper harness. they are abundant ecus, so make your life easier and get one that is 2-a. no, ripping out wires won't make your ecu run that engine right.

HondaPartsHero

If you go the P2E route you'll need to use a throttle body with the 3 wire IACV and do the necessary wiring at the ECU and find a 3 wire connector to wire in as your current engine uses a 2 wire. Just curious what happened to your old engine as it might be better to reuse or find a Y8 head and do a mini me.

Wrench6

Thanks, hatch, I didn't think that anything would change with removing the VTEC wiring from the ECU, it was just a thought. The P2E ECU is OBD2A so I should be good to go on that front.

Hero, I have the throttle body from the D15B engine, as it was on the intake manifold when I switched the D16Y8 intake and throttle body onto the D15B. As for the old engine... It simply took a ****. Dropped #3 cylinder, no compression. I had considered a rebuild, and I may still rebuild the D16Y8, as I still have it, but at the time, a replacement was cheaper than a rebuild.

eghatch9295

iTrader: (1)

right, he's saying youll need to convert from 2 to 3 wire idle air control valve. its pretty easy, there's a very detailed write up here.

Wrench6

Shouldn't be an issue. I'll collect all the necessary parts and keep you guys posted.

Thanks for the minutiae, it was the connecting of the dots that was escaping me.

Wrench6

I've read that using a Y8 Automatic Transmission throttle body will work because it is equipped with the 3-wire IACV and will run perfectly when connected to a P2C/P2E ECU.

Does anyone here have any experience/success with this swap?

eghatch9295

iTrader: (1)

yes, that should work. obviously, you would leave the old one where it is. youll need to do a little wiring, but no big deal.

Wrench6

Excellent!

So, I'll get:

The new P2E ECU.
A Y8 AT throttle body to mount onto my Y8 intake manifold.
A 3-wire IACV plug.
Spool of wire.

Thanks for all the help. Again, I'll keep you guys posted when I get this project completed.

Wrench6

Hatch, will there be an issue if I leave the Y8 manual transmission IACV mounted to the intake manifold?

If I remove the vacuum lines from the VTEC IACV and put them on the AT IACV that is on the AT throttle body, won't that cause some vacuum issues?

I'm thinking that I'll simply plug the vacuum lines that go into the VTEC IACV on the intake manifold when I switch the vacuum lines from it to the AT IACV that is on the throttle body.

NotARaCist

iTrader: (1)

Those aren't vacuum lines, they're coolant lines. You can pop them off the 2 wire IACV, and pop them on the 3 wire IACV, without problems.

Yes, there could be an issue if you leave the 2 wire IACV attached. Specifically, it could create a vacuum leak. Easy way around that would be to buy some sheet metal from your local Lowes, place the IACV on top of it, trace it, drill holes for the bolts, cut it out with a Dremel, then bolt the IACV back on with your newly fabricated blocking plate in there. Problem solved without having to replace your intake manifold.

Wrench6

Thanks, NotARaCist, exactly the answer that I was looking for.

eghatch9295

iTrader: (1)

ive not had a vac issue in the one car ive done this to, but you could always just buy vacuum nipple caps for the two ports if youre concerned

NotARaCist

iTrader: (1)

No need. The lines on the IACV aren't vacuum lines, like I said, they're coolant lines. You don't even need to cap the bungs on the old IACV. Just leave it there.

Wrench6

I'm thinking that I could forego all of this business by simply putting a new Y8 head on my D15B lower and just put the VTEC solenoid back on the head and plugging it in.

HondaPartsHero

Yep