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D16Y5 to D16Y8 swap questions.

19K views 25 replies 6 participants last post by  96HXcrap  
#1 · (Edited)
Hi guys, as title says, Did a HX to EX swap. 96'HX going to the 00EX.

Do you need to swap ECU and harness or just the engine and call it good?
 
#2 ·
Oh I picked up this 00EX for the donor which is a Auto. Mine btw is a manual.

If you do have to swap ECU and or harness, can I use these off this car, or do I need a manual ECU and manual harness? Not sure if there is diff in harness's from auto to manuals or not. So sorry if these qs sound dumb.
 
#5 ·
Oh and the Y5 has egr, this does not, if you just do the ECU, do you just leave this unplug'd and live with a poss. CEL light for that?
If you do just leave it unplugged then, do you cap it somehow?

And the Y5 at the IAC had 2 wire and this has 3 wires. Is there a correct method to re-wiring this then as well?

IF you swap ECU and it HAS to be a manual ECU, I can get a local off a 96-98 but it had cruise control. Would that throw a cel light for that too?
 
#6 · (Edited)
This sucks since the guy I took it to supposedly does swaps. But apparently he dont know jack about the HX to EX swap. Uugh. I need to get my car back working correctly very soon since I gotta go back to work by Weds.

He doesnt think you need to swap ecu's and that wont fix it. But something (or alot of things more like lol) is definately NOT right.
The car idles all over the place at diff speeds. This could be the IAC issue stated above. It idles at 800, most of the time at 1500. But then it idles at 1500-1700 rapidly at other times. And even other times it idles between 1000-1500.

Now the ECU thing, he also said a 00 ecu wouldnt work from this donor cuz it wont plug in to the harness. Well it is a P2P but from an auto. It has 4 plugs, my harness in the car (still og. Y5) has 3. I took it out today and it DID connect but is it the right one? I mean my car is man. and this being outta a auto makes me say... no and the fact that it has this extra plug spot too. IDK, just want to make sure before blowin the ecu or this newer used engine. Just trying to figure out if ANY P2P will work or if it's gotta be exact to what things you have like cruise to cruise control option and manual to manual or dont these things matter? and again any P2P will work?

And now I read something about the auto IM are diff. then the man IM and something about extra holes needing to be plugged or something. Uuugh this might be another issue since this donor was an auto.
 
#7 ·
complete Y8 , with your transmission. You need an obd2a to obd2b conversion harness to connect a 99-00 ECU(P2P) make sure you get a manual one.

Rywire - Online Store

You should be able to use your IM just plug off the EGR valve part. You shouldn't get a cel with the EGR unplugged since the Y8 is not looking for it.

P2P ecus are pretty cheap but I would make sure it meets your specs.
 
#8 · (Edited)
Yeah forgot to mention here that Im not using my HX tranny. Im using a Y8 from awhile back. sorry. So this car now has the following: the og Y5 harness, 00Y8 auto motor and IM and a Y8 tranny and now...

Just got his ecu that was from a 98EX This P2PA01. Plugged it in and these codes came up now:

1508, 0325, 0135, 0141. I get O141 since that has been here forever due to removing the HX cat and going to aftermarket EM.

The 1508 obviously is this IACV issue now. Apparerntly when he added this ground (3rd wire) it did not fix that issue.

Why the others are on IDK. thosse weren't on prior to swap or on the donor when I drove it there btw.
And I figured getting the supposedly correct P2P ecu that it would correct the "trailer jerking" effect I stated. This must lie within the IACV issue I guess. I feel no difference in ecu's from my HX one to this P2P one. But all I read so far said that was one of the things to do. Was hoping to be a step closer to the fix.

Id read about the IM on a manual is diff. then an auto and that might be the IACV fix I need, but don't have one in front of me to verify if it will except my 2 wire IACV plug or whatever.


Yeah, might have to resort back to my Y5 IM and block off the EGR like ya said, BUT... isnt the Y5s IM smaller/more restrictive and the TB smaller too? Kinda elminating part of the reason for this Y8 swap then..
 
#9 · (Edited)
i believe the harness must also be replaced or wires added for the addition of vtec? that could be the other codes. you have to hook up vtec switch vtec solenoid and knock sensor on the y8 the 98 ecu should work if its for an auto. the ecu may also run the trans but i was pretty sure there was a separate unit for it and any p2p would work as well. not the case. needs to be manual. why do you want to swap auto to manual? is that what you are planning to do? there is no reason. just use the following... complete y8 engine your hx trans find manual p2p and harness 96-00 just make the ecu year match the harness year. 99-00 had different plugs than 96-98. there is vacuum lines on the IM that need to be plugged as well.
 
#10 · (Edited)
Well my HX did have Vtec, a form of it called Vtec-E so dont know if that part is true.

My car was as I stated above, manual to begin with, this donor was the auto. I swapped out the Y5 tranny last year in put in a y8. The ecu is now officially out of a 98 EX Y8 manual so right now the harness, matches the ecu.

When this donor appeaered on CL for a great price I couldnt really pass it up. I was thinking of the engine with 1/3 the miles of my car. Didnt even faze me the this swap would be complicated being it was an auto at the time I picked it up. but the more I read, the more I wish I woulda just got a manual donor. LOL too late now.
 
#11 ·
You made this way more complicated than it should be.
no need to do a full swap. y5/y8 block is the same.
really all you need is the valvetrain and cam, rocker arms, vtec solinoid from the y8, and ecu/harness.
its actually pretty straight forward. especially since your rocking the hx tranny.
im stocking up stuff for this.

and it sounds like your guy doin the swap is a fool and shouldnt be touching Honda's.
 
#13 · (Edited)
Actually, I didnt make this more complicated at all. You see, my HX motor had 274,000 miles on her and was running on 3 outta 4 cylinders. I knew the block were the same and the head were different. I got a donor car cheap as stated above. This donor was an auto. my car has a manual....EX tranny as stated, not the HX.

I HAD to do the whole swap, my engine was dying fast. and I had a small window to get this swap done due to time off of work. The only issue, come to find out was that these autos have a diff. intake's then manual intakes. And of course the ecu is auto too.
 
#14 · (Edited)
Hunh, interesting cuz this 98 is running the car and has the exact same connections as my 96hx ecu. The auto plugged in but I never ran the car to verify that one. I now assume the 4th wire connection woulda been for the "auto" tranny wiring.



All is good now. As I found out after some research, these autos dont have the same intakes as the manuals. This was my main problem. All the post I read said to run a P2P so thats what I got as stated above. Now since I didn't have a Y8 intake and my car ran like crap with the auto intake (due to the diff. IACV 3 wire and those 4 tiny holes), what we ended up having to do, was pull the auto intake off, replace it with my od HX (Y5) manual intake. Left the EGR on as a block off plate. And all seems to be good now. Back to normal. Oh, we did leave in the Y8 injectors and the Y8 (P2P) ecu and of course swapped my Y5 TB too and had to swap fuel rails due to the EGR being in the way of course.

I went to the dealership before this and asked for pt numbers of a Y5 and a Y8 TB and the pt.#'s were the same. The TB and intake gaskets were also the same. Sooo this tells me the intakes (although using lareger Y8 inj, and the Y5 having a spot for the EGR, the size must be the same.

Now the only thing I wonder is if the Y8 manual intake is larger internally or something to allow more airflow? Maybe not since the Y5 and Y8 use the same TB pt.# though. IDK., hence why for now, I said F@uk it and did it this way to get me by. If it is larger internally then, I will have to get one and slap it then later.
 
#21 · (Edited)
Well, its been a few weeks now and I cant remember for sure, but this I know, The HX and EX intake gaskets were same at TB and motor. The TB was the exact same part number too. I forget if the intake itself was the same pt. # though. That is why before investing in one, would like to know if it is different or not. Why swap to it if not ya know. I was shocked to see the TB was the exact same pt. Figurred that would be a tad bigger to allow more airflow. It would seem odd they would make the EX intake bigger than if these TB are the same ya know?


I ask about the knock sensor ordeal since that code is on right now. I thought I recall him saying this new(er) motor had 2 and he had only 1 plugged in due to obviously my harness.
 
#22 · (Edited)
Ok this could be why this knock sensor code is on. So maybe the HX had 1 sensor and the 00 EX (and maybe 96-98 ) have 2.
I dont see any plug/wire for this either.

I took a pic of the 00 EX harness and it shows 3 plugs coming out this location. Obviously one is the KS plug (M gray one) (L) gray plug and this (R) black cone plug, IDK where or what they go to,but these 2 are plugged in. Could it be this black cone plug is also a knock sensor then? and again meaning the HX apparently had 1 KS and this 00EX has 2??. :(

Image

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I wonder if this is the case, If should go back to my HX ecu till this gets figured out. At least that code would be off then. Might create other issues?? IDK.

Wonder if ok to drive like this still till??. Seems to run ok. But then again, I was driving on 3 cyls. for a few months before this swap, so anything drives better! lol
 
#24 ·
looks like, white/red, brown/?, and blue/red it looks. -Again these two are plugged in its this middle one, the knock sensor that is not and does not have a wire/plug for it.

Hmmmn...........ok, then maybe the HX did not have a knock sensor??, since Im still running my HX harness with a 96-98 ex ecu he gave me

So then does 96-00 EX have these 3 extra wires coming out like in this pic of the 00EX? If thats the case and I have this 96-98 ecu allready, then maybe I can just get a 96-98EX harness instead of trying to get a 00 harness and ecu too.
 
#26 · (Edited)
Are you talking about a knock sensor on the HX's?

Yeah, well thats what I thought too or maybe its in an entirely diff. spot? Weird. I dont see any plugs not plugged in thats the funny thing.

Now Im wondering which way to go on the harness's. 96-98 or 99-00? I do have this auto harness and heard you could use it but leave the middle plug out (tranny) of the ecu and just leave the (auto) tranny plugs that are in the engine bay just hanging. Dont really like the idea of having wires hanging and poss getting in the way of other stuff and poss. melting/catching fire or some crap ya know. But, worse case scenario I guess that is what it will be.