hatch had a b18 motor with a 99 interior including dash harness but the motor was replaced with a d16y7 block with a d16y8 head with the vtec not connected. computer is for the b18 obd1 with a jumper to connect it to the harness. not sure which engine harness is in it (has a few plugs not connected) . car runs fine except for a few idle issues and check engine light stays on which figures since it is a frankenswap.

my question is what is the easiest way to get this car back to a d16y8 vtec operating correctly with obd2b parameters. can I use the block and y8 head and just get a vtec engine harness for a 99 civic along with the 99 ecu? I am looking for a vtec equipped engine that works correctly with obd2b computer. I will be putting a vx trans on it but want the obd2b running since I want to connect a scan guage. I am not opposed to obd2a but if I understand correctly it will not match up with the 99 dash harness this car has. I don't want to go back to obd1 as I want to run a scan guage on it to actively monitor fuel economy. I am not going for a performance build I want a fuel saver. just wondering if the y7 block and y8 head will hook right up to an obd2b harness and ecu and run right regardless of the year of the engine.
I am open to other motor ideas but am looking for one that is minimal trouble to replace. I would really like to install a jdm dual vtec engine but from what I understand this wont run right on OBD2? again the key elements I am looking for are that it needs to be OBD2, and also a fuel saving engine, minimal trouble to swap (don't really want to redo the dash harness back to obd2a).

any ideas appreciated. I have replaced civic engines but have never swapped anything in a 96-00 my only experience up till now has been ob1 in the 92-95 range. trying to get the car up to norm with minimal trouble.

 

Obd2b p2p y8 ecu and connect plugs correctly. Should work easy then

 

how can I tell if the engine harness is correct for the y7 block/y8 head and the 99 ecu I am going to install?

are the 96-98 harness for the engine the same as the 99-00 harness? the hatch is a 98 model 5 spd that had the b18 swap into it at one point but I am not sure if the harness is the original dx harness, or a b18 harness or the y8 harness. I do know the dash harness is a 99 and it has a obd1 ecu connected with a jumper (thank god no cut wires). I hate to buy another y8 m/t harness if I can use the one I have with a 99 up ecu but will if needed.

 

also is it possible to install the jdm dual vtec d15b into this car and still have functional OBD2 with a 99 dash harness as long as I get the ecu, and engine wiring harness package with the d15b?

if I did that I could use the y8 motor in a different car and recoup some of my money like that so I am not opposed to that idea but don't want the
d15b if I cant get the obd2 to run properly.

again hatch is a 98 5 spd with a 99 dash including the harness. will obd2b dash harness work with the jdm d15b dual vtec?

 

you're all over the place...you have a d16y8 head and a y7 block just get a y8 block then you have a complete y8 not that the y8/y7 block are different. and 98 is obd2a why you want obd2B is beyond me since you're not in that chassis obd bracket


Edit HOW do you know the whole dash harness was changed to obd2b pics of the current ECU ?

 

If your engine and dash harness are OBD2B still your only option is to run the 99-00 P2P ECU. Then you'll need to at least run the wires for VTEC and knock sensor. I'm not sure what plugs aren't connected so you can post pictures.

 

I understand it is confusing, that is why I am here asking for advice. I will clarify what I can. I don't care if it ends up obd2a or obd2b but as long as it is obd2 something.

I am positive the dash harness is obd2b since it was from a 99 civic, that much I was able to ascertain from the previous owner.
from what I have read it looks like if I have obd2b dash harness I need a obd2b ecu that is why I care whether it is an a or b setup.

the engine harness is what I a not sure of. he did not know. the only thing he knew was that it USED to have a b18 in it and was replaced with a y7 block with a y8 head. (vtec not connected)

ecu is obd1 with a jumper.

trying to just get it back to obd2 the easiest route possible for now. trying not to waste money. love to know if the harness would work or not or if I have to spend the money to get a 99 y8 harness as well as the 99 ecu which I need.

again I would also really like to know if I can run a d15b dual vtec if I get the complete swap ( engine, harness, and p2j-j11 ecu) that setup is available at local jdm depot and then I could throw the current engine into another civic shell I have and sell. almost be cheaper and I would like to have the dual vtec for the low rpm efficiency mode. will this setup work properly as obd2 in this car. most of the setups I see seem to require a lot of mods and a lot of people seem to retro back to obd1 for performance. not much data on just having a relatively stock d15b dual vtec with the p2j j11 ecu. I am not sure if the retros are necessary,performance related or just because they did not have the right ecu to begin with. I don't want to use an rpm activated switch, if the ecu wont run it then I don't want dual vtec but it sounds from the jdm place like if I get the whole setup as listed above it would run properly? I just hate to spend 1400 on that and then find out it wont run properly ( both vtecs) or match up to my dash harness and then I end up having to tear that out and swap it also. I just started new job and am busy way more than I used to be and need a pretty turn key swap as time is what I am most short of for now.

I am open to any ideas from the h tech swap gurus. my only swap experience for now has been a zc into my d15b7 lx and a z6 into a z6 and a few trans swaps for mileage improvement and bad bearings. never tried anyting else..

I will try to post some pics of the harness and ecu number currently in it. if the d15b dual vtec complete swap will work then I really think I will just go with that, love to be able to make sure before I spend for it though

 

what plugs are on your engine harness?

 

If I remember correctly, I believe the reason people went OBDI with the 3 stage jdm motor was due to emissions. I thought I read people saying they wouldn't pass emissions running the stock ECU for the motor being Japan has different standards, and is why the motor wasn't released in North America. I could be mistaken but I think this is why people avoided the stock ECU and went OBDI.

 

The pic kyden posted will help you know if it's an obd2A/B dash harness, as for the engine harness it doesn't matter as much afaik the alt and distributer plug are slightly different between A/B. But maybe not and they could just the be the same in which case no worries. you won't pass emissions with an older engine is a new car btw so re think that d15b

 

The 3 stage D15B is OBD2. A couple of things about the P2J ecu, one related to you wanting to use a scan gauge as you called it the otherr as to why people go OBD1.

The P2J will not connect with whatever scanner you connect to it if you're in North America so that kills you reason for staying OBD2 and this engine/ecu. The other part of this is if you have emissions testing where they plug into the DLC you'll fail, again because the ecu won't connect the the scanner.

If you weren't concerned about the above two things then it would plug and play fine.


A couple of reasons people go OBD1 is they may be intalling it into an OBD1 chassis. The P2J ecu isn't very common and many of them are for the CVT transmission. I don't think the auto to manual trans mod works on OBD2 ecu's. A lot of people get this engine having no clue, they just thing ZOMG, three stage Vtak.

The easiest way for you to get back to OBD2 is is determine your engine harness type, confirm the dash harness, remove the OBD2 to 1 jumper and get a P2P ecu that matches you harness.

 

ok, great help with the replies. really appreciate it. thanks for the pics of the ecu I was able to figure out what I had and it is def obd2b based on the above pics

I just bought this hatch and was going by what the previous owner who was clueless about the swaps done for the most part said. today I finally had time to go inspect it. here is what I found:

it does not have an OBD1 jumper, just 99-00 obd2b swapped dash harness and ecu. previously it had a b18 in it not sure which one

the ECU is a P2T-A12 which it seems comes from a 99-00 obd2b civic si

the engine wiring is so riced out it is not even funny. O2 sensor is not connected (just dangling) and I cant find the plug it connects to anywhere, it has a ton of plugs hanging on it that I have never seen before on any of my 92-95 civics (one on the timing belt side which I believe is the CKP sensor, one on the intake manifold and one under the distributor).

the hatch used to be an auto and was converted so maybe one or two of those were from an auto harness?

it is hard to believe it even runs but it actually runs pretty well just has an occasional idle issue where it wants to hang at 3k when you are stopping and you have to bump the throttle to get it down and then usually idles 1k to 2k but does'n't hunt just randomly picks a spot and sits there...lol

check engine light is on of course.

the advice about the jdm 3 stage vtec not working with a scan guage saves me a ton of headache as the only reason I was hung on obd2 was so I could run a scan guage which runs 24/7 and monitors fuel economy etc and posts to a display.

I naively thought that 96-00 would be the same jdm or us and did not realize that the obd crud would not communicate.

now that I know this much I am open to advice. after inspecting it today I really think the engine wiring harness is trash. so many brittle wires, lots of extra plugs and ironically a few missing like the O2 sensor connection which I have yet to even find...it is generally riced in every bad sense of the word.

the ecu as mentioned is P2T-a12. car is 5spd. dash harness is def 99-00 flavor. current motor is y7 block with y8 head. vtec is connected has plugs for vtec and all that but looks very sketchy.

I don't have emissions where I live which makes life easier.

I really don't care about speed, car just needs to have ordinary D block power as it is going ot be a back and forth to work roller skate/fuel saver. I was interested in the 3 stage vtec because of the lean mode it has not for speed reasons.

can I use the existing P2T-a12 ecu to run the y7/y8 combo if I get a new engine harness (99-00 m/t for an ex)? or do I have to swap in the ex ecu as well? if the d15 wont run obd2 correctly then I am not really that interested in it but might get it if I have to get to much stuff to get this one running correctly.

again I really appreciate all the help. I fully understand how jacked up this thread is but if you feel the need to point it out be my guest. it has already given me a bunch of great info and I appreciate all input. if anyone has a clear common sense idea of a swap that will preserve fuel economy with AVAILABLE engines that are worth swapping in I am open to ideas.

 

Like already mentioned for your engine combo you would want a P2P ecu, the P2T is less than ideal for the engine and your wants/needs.

You'll want to get the engine harness sorted or replace it. With clear pictures of the plugs clearly showing wire colors we can help figure out what's not connect and whether it's needed.

With what you have you get good economy if you get everything squared away.

 

ok. pics coming up. will hunt up a p2p ecu and a price a harness for it

 

here are some pics few moreto come along with wire color clarifications

 

wire in first and second pic is zip tied to intake mani below fuel rail. has three wires. they are white, black and blue.

wire in the bottom two pics is also by the intake manifold and is a two pin connector wire colors are blue c red stripe and white with red stripe

3rd and 4th pic from top are of a weird looking plug with a plastic tip end I am not even sure what this is but don't recognize it from my 92-95 civics it has two wires:
green with black stripe and red with a yellow stripe. any info on this also much appreciated.

5th down is a single black wire with a white stripe. it appears to be a large guage wire. was taped up.

also few random pics including one showing that the brown plug on the thermostat housing has no plug on it and can find none that go to it? thought car needed this to run correctly? it has some wires down inside the plug housing crammed and twisted together?

will post a pic of the ecu/wiring next

 

here are pics of the ecu and wiring connected to it

 

 

 

thanks for the help idíng the plugs. lol, that is the signal wire for the starter. he has it jumped to a toggle switch after the key Is on due to the interlock swtich being out... I forgot about that little mod.

what kind of harness does this look like? one from a d16y8 or is it from a B18? and do you think it is worth trying to get it right once I get the new ecu or better off getting another clean engine harness and running that with the new ecu?

any idea where I can find the O2 sensor wiring? the plug is just hanging there but I cant find anything for it, any tips on where that might be would be appreciated

 

I looked a little more and here's what I thing. The three wire CKF plug is the plug for the sensor itself. The two wire plug in the same area (blu/red, wht/red) is the harness side CKF plug. With the CKF being two wire on the harness I think it came from the same car the cabin harness came out of, 99-00 SI , B16A2


The primary O2 plug should be around/under the distributor, the seconday O2 plug is part of the cabin harness on the EX/SI, under the center console.

 

thanks for the update, so it looks like i have to decide between swapping in a whole new setup (looking better and better) or getting a new harness/ecu and installing it. obviously the latter would be cheaper but i am wondering how successful i will be at getting it back to functional...again i cant believe this car runs as well as it does set up like this.

going to look for o2 sensor plug again... not even a trace of a plug or cut wires in that area last time i looked..very frustrating... i looked where my 95 o2 sensor connects and then went over to this one and compared and zero luck...wtf??

can anyone recommend any good shop in Houston area to do the basic d15 swap ( complete swap if I do it it will be harness/ecu/engine/trans) I just started a new job and get very few days off...the more i look at this wiring the more i am sure i want to get rid of it ...will probably just sell the y7/y8 combo as is and let someone else have at it...or wait till i get some time off and throw it in another car with the right wiring/ecu

 

I would seriously just keep the engine as is. There's nothing wrong with the Y7/Y8, basically the same as a complete Y8. With the proper ecu and a repaired or replacement engine harness it can be a reliable/economical set upp with proper maintenance.

Paying to pull it and replace it with a 1.5 make no sense at all.

 

thanks for all the advice/help nub.

i have been looking at harnesses...they are not as cheap as i would like them to be..lol.. sure will cry if it doesn't fix it..
will i need a knock sensor when i get my y8 harness? don't think the car currently has one but need to verify...

 

The y8 one should have the plug and your block should all ready have ne even if it's not hooked up. Rywire and chase bay one's start at 350-430$ tho hardly steep in terms of you were thinking of getting a d15b(3-400$), Well worth it if you did decide to get one I love my mil-spec one.