Obd2 Car Obd1 Engine & Wiring

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SpeX

Junior Member
I've been doing as much research as posssible before I go into this project and I can't seem to find a straight answer for putting a OBD1 engine in a OBD2 car. First off I don't wanna convert the engine to OBD2. The only answer I have come up with is having to convert my whole dash wiring to OBD1. Alot of people say just get a wiring harness adapter, but I want to use a OBD1 engine harness so that idea is out. right? I have thought about putting a OBD2 end on my OBD1 engine harness then getting a conversion harness to run my OBD1 ECU, but I can't find anyone out there that has done this and documented it. PLEASE HELP, I need some direction is this area.
 

asmallsol

Super Moderator
it is extremly challenging (sp?) some guy who said he knew what he was doing took him over a month to wire it. Is it possible to do this swap, yes. Is it practical, no. Have you already bought the engine? If not, just spend the extra 100 and buy the OBD2 model.
 

Vexamus

Member
It's not actually a question of the "type" of engine, but rather the ECU itself, since they probably plug up just the same.

Determine what ECU you're going to use, if you're going to use an OBDI ECU, then buy(or fashion) yourself an OBDII to OBDI conversion harness.

Use the OBDII harness that's already in your car, you may have to shorten/lengthen a wire or two and/or change out maybe ONE sensor. But I don't think that's even an issue. Seeing as how anyone with an OBDII car(say a lude for example) can swap out ECU's for an OBDI ecu with the adapter harness. Easy peasy, nice and easy.

Contact me if you've any further questions.
 

SpeX

Junior Member
I bought a 95 Integra awhile ago and recently got a 97 CX Hatch with a swap in mind. The wiring harness doesn't even look close to the B18c it seems like there are alot more sensors and stuff on the GSR motor. IS there any sites that have detailed info on using a CX harness on a B18C engine?
 

longlee

Junior Member
ah.. this is the same swap im doing right now and i seem to have problems also...only the motor is obd2...first you gotta let me know if you have the small plug that plugs into the ecu.. if you do then i got an obd2 gsr ecu that would fit perfectly .....thats if you have the small plug...i dont know how much a 2000 hatch differs from a 97 hatch but if you have that little plug that plugs into the smallest plug available then obd2 is for you....for me i dont have that small plug so i cant use the obd2...i need to convert into obd1 so when you determine if it will work maybe we can swap ecus or something...i tried the obd2 ecu into a 98 civic ex and all the three plugs fit perfect and the ecu doesnt throw any codes...let me know so we both can eventually get our problems solved....
 

posol

RETIRED
check out our swap section. 6th gen. you will find how to wire an obd1 gsr into a 6th gen. you need to swap the IAB controls
 

SpeX

Junior Member
Sorry, longlee. I don't wanna convert my motor OBDII. It involves to much extra work, for something I already have complete (injectors, distributer and on a B18c a oil pump sensor)

Its been a couple of days, but I have a few more shots in the dark for you guys. On honda-tech a couple of people were saying the plugged in there OBDII swaps into there factory OBDI cabin harness (the opposite way of which I want to go, I know) I'm not sure if there talking about where it comes apart by the passenger shock tower or in the car itself. This was making me think why can't I do the same thing with my OBDI B18c engine harness and get a OBDII B18c cabin harness? If I'm right the OBDII Civic doesn't come apart on the shock tower but the Integra does, in that case run OBDII cabin harness to OBDI engine harness, get OBDII to 1 converter and plug in my ECU:)? RIGHT? PLEASE CORRECT ME IF I'M WRONG. I am just trying to look into every viable option other than repinning my whole wiring harness.

Also pissedoffsol, I have gone through the site numerious times and I can seem to find what your talking about. Only thing I see is If you did not buy an obd2 swap for your 6th gen, things get much more complicated, and we will attempt to tackel that sometime down the road.
THIS is pretty much what I found everywhere from all of my research on the internet in 2 weeks. PLEASE just a straight answer from the OBD GOD!
 

masqjode

Junior Member
OBD1 B-series Wiring Guide

Wiring an OBD1 VTEC B-series into a 92-95 Civic

The most common cars for swaps are the EG-chassis line of Civics. Since there were way more base models produced than EX/Si models, chances are that your car is not already wired for a VTEC swap. Here's a quick chart of what to check when wiring in your 94-95 Integra B18C1 or 94-95 del Sol VTEC B16A3 into your EG. Most jdm motors will also follow this guide, but some changes will be made to your stock harness for it to work properly. Ensure that the following are all hooked up before you get any deeper into trying to figure out what's wrong.

B16A3/P30: 6 wires
Engine ECU
Part Wires Pin-out
VTEC Solenoid Yellow/Green A4
VTEC Oil Pressure Sensor Blue D6
VTEC Ground Black Chassis Ground
Knock Sensor Red/Blue D3
Evap Purge Power Yellow/Black 12V Power
Evap Purge Solenoid Red A20

B18C1/P72 and h22/p13: 7 wires
Engine ECU Side
Part Wires Pin-out
VTEC Solenoid Yellow/Green A4
VTEC Oil Pressure Sensor Blue D6
VTEC Ground Black Chassis Ground
Knock Sensor Red/Blue D3
Evap Purge Power Yellow/Black 12V Power
Evap Purge Solenoid Red A20
Secondary Intake Solenoid (IAB) Pink/Blue A17

If you have an EX/Si/VX most of these are already ran. Also, it has been our experience that most 1992 Civics, regardless of the trim level, are all wired for VTEC already. When doing a GSR swap, all that needs to be run is the knock sensor and the IAB's. For the rest of the model years, and the lower trims, you will need to run all of these wires. The professional way to do this is to actually re-pin the harness connector on the passenger side shock tower to accept these new wires and re-pin the ECU connector harness as well. Re-pinning tools are fairly inexpensive and can be found at most electronics stores. This way, you can simply plug in your obd1 GSR or del Sol VTEC motor with its harness right into your car. it retains the stock look, and makes your swap look much more professional than simply duct taping wiring together. It is also a good idea to wrap the new wires in loom much like the stock harness parts are.
 

posol

RETIRED
why would you bump a 3 year old topic to paste the text of an article that is already in our reference section?
 

civic_import

New Member
first of all i know this thread is old, but i kept coming across it when looking for info on how to rewire a OBD2 alternator to OBD1 when doing my B-series swap.

i can say i was not able to find anything on the net, but there is an easier way to do this.
i used my old OBD1 alt for my D15B engine,

first you need to remove the 8mm nuts on the back of the alt
then remove the metal cover
then you need to remove 4 screws which hold the heat sink and the round conector to the alt, once all the 4 screws have been removed slide the heat sink and plug.

now get your OBD2 alt for the B-series engine and do the same as above,
then get the heat sink and socket from the OBD1 alt and put it in the new OBD2 alt, all screws will line up. then all you will need to do now is trim some of the metal cover around the plug socket screw the cover back on and your done.

took me about 5 minutes max, and works fine. trust me is alot easier than cutting the wirers and solding a different plug on.

hope this info helps
 

mrdathion

New Member
heyI have a simliar problem with my prelude. I currently doiing a odb2 to odb1 jdm h22a swap. I done the whole swap completly now. I swaped out a h23 4 the h22. I used the h23 engine harness. I gotten the odb2 to obd1 conversion harness. everything is hooked up. I ran the vtec wires and alshey I currently doiing a odb2 to odb1 jdm h22a swap. I done the whole swap completly now. I swaped out a h23 4 the h22. I used the h23 engine harness. I gotten the odb2 to obd1 conversion harness. everything is hooked up. I ran the vtec wires and also put in a vtec controller. the engine had a internal coil. the car had a external coil. i used the h23 dizzy with a new ignitor . every thing turns over fuel pumps work everything is ready but I have no spark and I cant figure out y. I also sasddly do not know how to check 4 codes on a obd1 car. does anyone have any idea what I could be doing wrong. o put in a vtec controller. the engine had a internal coil. the car had a external coil. i used the h23 dizzy with a new ignitor . every thing turns over fuel pumps work everything is ready but I have no spark and I cant figure out y. I also sasddly do not know how to check 4 codes on a obd1 car. does anyone have any idea what I could be doing wrong.
 

pressurecooker

New Member
sorry to bring up the past but i' ve got a '98 hatch with an obd1 wiring conversion in the cabin and a D16y8 Si EX in US engine, I just put in with the wiring & ECU. It runs, now I just need to run my secondary 02 sensor(on CAT) to the main wiring, but don't know if there is an existing harness behind dash to do it. Do I have to pull dash & rewire the whole thing with obd 2 wiring for it to work, or do I have any other options. I have no wiring experience, looking 4 guidance.PLS
 
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madracer

Boosting B16A2
I've been doing as much research as posssible before I go into this project and I can't seem to find a straight answer for putting a OBD1 engine in a OBD2 car. First off I don't wanna convert the engine to OBD2. The only answer I have come up with is having to convert my whole dash wiring to OBD1. Alot of people say just get a wiring harness adapter, but I want to use a OBD1 engine harness so that idea is out. right? I have thought about putting a OBD2 end on my OBD1 engine harness then getting a conversion harness to run my OBD1 ECU, but I can't find anyone out there that has done this and documented it. PLEASE HELP, I need some direction is this area.

If i understand you correctly, you have a OBD2 set-up right now and you planning to put a Motor that have been wired for OBD1???? then your car have a OBD2 computer?????? Well all you have to do is put a OBD1 computer and get a OBD2 to OBD1 harness which the harness cost about 75.00 in most places and you all set just plug and play. How ever if your motor has add ons or built internal parts you will have to get the OBD1 computer chipped and tune for the car which is not all that expensive and the motor will run top notch.
good luck.
 

Mikey97hx

New Member
So if i have a 97 hx with a blown motor and i came across a single cam vtec zc obd1, and i just go get a obd1 p28 ecu and adapter harness it should work no problem? or what????
Any input is appreciated, thanks
 

hondaman119

New Member
hasport obdi1 engine harness to run my b16a in dx crx for sale

the harness is for sale for 200.00 call 651-690-6518 ask for crosby
 

fionntan

Banned
I wonder if this is the longest running thread on hondaswap.

Started 2003 and is still being bumped in 2010.
 
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