Kurts OBD0-OBD1
Library.KurtsOBD0-OBD1 · r1.1 · · guest
First attempt to post this OBD1 conversion write-up on wiki.pgmfi.org. Some sections need revision still and they are in italics/bold print. Please send any suggestions to me at [email protected] .
D16Z6 installation and OBD0 (88-91) to OBD1 (92-95) wiring conversion - By Kurt_W
Contributions by ~StorminMatt and Noahk (of CRX Resource)
Original April 2001 version reviewed by Lynne R
Slightly improved starting Nov. 2 2003
This conversion is to an 89 CRX Si though it can also be done to any 4th generation Civic or 2nd generation CRX. It should be also be noted that this conversion can be done using any of the newer D-series Honda engines even though this particular write-up is specifically for a D16Z6 installation. The newer D16Y8 is also a suitable alternative to the D16Z6. I personally have not done a D16Y8 swap, so all particulars are not known to me therefore no information about swapping a Y8 will be included in this write-up (at this time.) Any references to sources for parts are simply for reference. The writers and contributors do not necessarily endorse this institutions. List of the parts used/modified #One slightly used 89 CRX Si #93 D16Z6 (also known as Z6) 1.6L SOHC VTEC #Partial engine harness from the 93 D16Z6 and harness parts (specifically ECU plugs) from a 92 Civic DX (automatic) #95 Civic EX P28 ECU (manual) #92 Civic Si distributor # #4107 fuel injectors years unknown (more on this later) # 1984-1991 ChiltonÂs Honda Civic/CRX and 1992-1995 Haynes Honda Civic/Del Sol manual or suitable Helms/Honda shop manualsOBD0 to OBD1 conversion
This was interesting, ordeal yes, ordeal was the correct word. Over all, the process took about 15 hours. Several hours were spent looking over the instructions received from ~StorminMatt for the process making sure theyÂre correct (listed below). The engine harness had to be modified and either the dash harness modified or a converter built to allow the OBD1 ECU to be plugged into the 89 dash harness. UPDATE: Since I originally wrote this write-up, the OBD1 conversion has become much more popular therefore pre-built conversion harnesses are available. Most are home built by private individuals, but I donÂt know of anyone in particular that makes them. Engine Harness Conversion It is necessary to convert the stock harness from the car to which the swap is being done. The OBD1 engine harness will not plug into the OBD0 engine harness due to incompatible plugs. It may be possible to change all the plugs (by removing the gray plugs from the OBD1 harness and replacing the white ones with them on the OBD0 harness) and use the complete OBD1 harness. This was not attempted due to not having the complete OBD1 to work with. Note: Removing the engine harness is recommended to make it easier to modify. Wire colors will be listed in this manner red/grn (indicates red wire with a green stripe). Many wires can be pulled out of plugs by pushing in the front with a small screwdriver for example while giving a gentle tug on the back of the wire. 1. Injection Resistor: There are two ways to deal with the injection resistor and fuel injectors:- Retain the original MPFI fuel injectors and injection resistor. This is the simplest way to go. (Thanks Noahk)
- Convert to the newer injectors. To do this, pull the yel/blk wire from the green plug on the injection resistor. It will be relocated into an open space in a gray 8 wire plug from the OBD1 harness. This OBD1 plug has 8 yel/blk wires leading from it and has a gray cap on it. Removing the cap shows that it has an integrated metal clip that connects all the yel/blk wires together.
- When retaining the original MPFI injectors and injection resistor, nothing needs to be done.
- To use the OBD1 injectors, the injector plugs from the OBD1 harness must be used. Each plug has a different color line (brown, red, light blue and plain yellow = 1, 2,3,4 injectors respectively) and a yel/blk wire leading from it. The yel/blk wire from each of the injector plugs leads back to the 8 wire plug mentioned in step #1. The OBD0 injector plugs must be cut off and the OBD1 injector plugs soldered on. Match the injector colors to each other, as they are the same on both the OBD0 and OBD1 harnesses. Note: On the OBD0 harness, the wire leading from the injector plug to the injector resistor is red/blk. DonÂt worry about these wires as they only connect the OBD0 injector plug to the injector resistor.
Dash/In Car Harness conversion
This is the fun stuff. There are two ways to do this. Note: Using 92 Civic ECU (OBD1) plugs is best for this conversion because it has all the necessary wires for the Z6 ECU. If 92 ECU plugs canÂt be found try to get the plugs from a Si or EX, otherwise additional wires will need to be added. If these instructions are used for an OBD1 B-series, a knock sensor wire will also need to be added to the plugs (unless ECU plugs from an OBD1 Del Sol VTEC are used). 1. Build a conversion harness using the male ECU plugs from a 92 Civic or similar and the female plugs from an OBD0 ECU. To get the plugs off the OBD0 ECU, unsolder or if necessary cut the ECU board with a Dremel tool equipped with a cutoff blade. After the plugs are taken out and cleaned up, the wires from the OBD1 ECU plugs can be soldered onto the proper pins from the OBD0 plugs. See below for proper combinations. In addition to matching the wires, 3 wires will have to be routed into the harness to meet up with the OBD1 plugs. These wires are the VTEC wire, the VTEC oil pressure wire and an O2 sensor wire. This is more easily accomplished if done using the a pre-built OBD0 -OBD1 conversion harness as mentioned about in ÂUPDATE OR 2. Cut off the OBD0 ECU wire plugs and splice the wires from the OBD1 ECU plugs to the wires from the OBD0 harness as listed below. You will also have to attach the 3 extra wires mentioned above in method #1. OR 3. Unpin all the wires from the OBD0 connectors. The majority of them are the same size as the "small" OBD1 pins and can simply be inserted into the appropriate spot. The "large" OBD1 pins will need to be crimped or spliced on. (Dave's note) Here is the information on the wiring the OBD1 ECU. ItÂs originally by ~StorminMatt (thanks Matt) from CRX Resource. Several additions have been made to the listing in the hope of making it more helpful and easy to understand, however, his post has been mostly left intact because he explained it well. ÂA number of people have asked me how to change the 1988-1991 ECU plugs to 1992-1995 plugs in order to use a 1992-1995 ECU for any one of a number of applications (SOHC VTEC, 2G B16A, 1992+ B18A/B18B, B17A, B18C, etc.). I figured it would be best to just make one post with this information rather than having to email everybody separately with this information. There are a couple of things to remember here. I personally prefer the numbering system where Honda numbers the pins across rather than the zig-zag system. But I realize a lot of people may prefer or are used to the zig-zag system. So for each pin (on each plug style), I list two locations for the same pin. The first is given by numbering across. The second (in parenthesis) is by the zig-zag numbering (I hope it is correct). In case I made any errors in conversion AND to make the process of changing the plugs over more goof proof, I also give the color of the wire on the 1992-1995 plug and 1988-1991 plug for the given pins. This should give you a better idea of whether you are connecting the wires together correctly. Also, the first set of pin numbers and wire colors are all on the 1992-1995 plugs and the second set of pin numbers in brackets are the 1988-1991 plugs.A plug (1992-1995 plug) A1 (A1) ----> A1 (A1) Injector 1 brn --------> brn A2 (A3) ----> A2 (A3) Injector 2 red --------> red A3 (A5) ----> A3 (A5) Injector 3 lt. blu ----> lt. blu A4 (A7) ----> A14 (A12) Main Relay grn/yel ----> grn/blk A5 (A9) ----> A5 (A11) EACV grn/wht ----> blu/yel A7 (A13) ---> B13 (B6) Check Engine Light grn/org ----> grn/org A8 (A15) ---> B2 (B3) A/C Clutch Relay blk/red ----> yel A11 (A21) --> B8 (B15) Ignition Unit Signal red/grn ----> wht A12 (A23) --> A9 (A2) Main Relay blk --------> blk A13 (A25) --> A6 (A13) Main Relay yel/blk ----> yel/blk A14 (A2) ---> A4 (A7) Injector 4 yel --------> yel A15 (A4) ---> (VTEC) grn/yel on the engine harness, your choice elsewhere org/wht ----> (your choice) A16 (A6) ---> (O2S heater) to org/blk on engine harness, your choice elsewhere org/blk ----> (your choice) A17 (A8) ---> A15 (A14) Main Relay grn/yel ----> grn/blk A19 (A12) --> B12 (B4) Radiator Fan Relay yel/grn ----> yel/grn A21 (A16) --> B3 (B5) Alternator wht/yel ----> wht/yel A23 (A20) --> A11 (A6) Purge Control Solenoid red --------> grn A24 (A22) --> B9 (B17) Ignitor Unit red/grn --------> wht A25 (A24) --> A10 (A4) Ground blk --------> blk A26 (A26) --> A17 (A18) ÂMultiground blk/red ----> blk/red B Plug (1992-1995 plug) B1 (B1) ----> A7 (A15) Main Relay yel/blk ----> yel/blk B3 (B5) ----> B14 (B8) A/C Switch blu/red ----> blu/red B5 (B9) ----> B7 (B13) Main Relay blu/wht ----> blu/wht B6 (B11) ---> B15 (B10) * org --------> org B7 (B13) ---> C2 (C3) * org/blu ----> org/blu B8 (B15) ---> C1 (C1) * blu/grn ----> blu/grn B9 (B2) ----> A16 (A16) Multiground brn/blk ----> brn/blk B13 (B10) --> B18 (B16) Vehicle Speed Sensor yel/blu ----> yel/red B14 (B12) --> B16 (B12) * wht --------> wht B15 (B14) --> C10 (C4) * wht/blu ----> wht/blu B16 (B16) --> C9 (C2) * blu/yel ----> blu/yel D Plug (1992-1995 Plug - No C plug on 1992-1995 Plugs) D1 (D1) ----> B1 (B1) Hazard wht/blu ----> wht/grn D2 (D3) ----> (Knock Sensor) B-series engines only! red/blu ----> (your choice shielded wire) D5 (D9) ----> B17 (B14) Alternator pnk --------> blu D6 (D11) ---> C4 (C7) Throttle Position Sensor red/blu(or pastel green) ----> red/blu D7 (D13) ---> C11 (C6) Coolant Temperature Sensor red/wht ----> red/wht D8 (D15) ---> C3 (C5) Intake temperature red/yel ----> red/yel D9 (D17) ---> C6 (C11) Map Sensor wht --------> wht D10 (D19) --> C8 (C15) Map Sensor yel/grn ----> yel/red D11 (D21) --> C15 (C14) Map Sensor grn/blu ----> grn/wht D12 (D2) ---> C13 (C10) Brake Switch grn/wht ----> grn/wht D13 (D4) ---> B20 (B20) Service Connector brn --------> brn D14 (D6) ---> (VTEC Pressure Switch) Blue/blk wire in engine harness org/blu ----> (your choice) D16 (D10) --> B10 (B19) Electronic Load Sensor grn/red ----> grn/red D18 (D14) --> C16 (C16) O2 Sensor wht --------> wht D21 (D20) --> C7 (C13) Throttle Position Sensor yel/wht ----> yel/wht D22 (D22) --> C14 (C12) Coolant temp/TPS/O2/etc ground kind of thing grn/wht ----> grn/whtThe pins marked * connect to the distributor sensors (crank angle, TDC, and CYP) and while 1988-1991 and 1992-1995 cars both use the same color wires collectively for these sensors (org, org/blu, wht, wht/blu, blu/grn, blu/yel), wires of a given color do NOT necessarily connect to the same sensors in the 1992-1995 cars as in 1988-1991 cars. So if you check the Hasport pin-out, the connections I gave will be incorrect. However, itÂs actually easier to just match up like colors. If you do this, just remember to match the proper colors on the distributor plug as well. In other words, the org wire on the 1988-1991 engine harness goes into the same spot on the 1992-1995 distributor plug that the org wire went to on the 1992-1995 engine harness. Just don't confuse the fat white wire with the thin white wire on the distributor plug of the 1988-1991 engine harness. The fat white wire on the 1988-1991 harness goes where the fat yel/grn wire on the 1992-1995 harness went (on the 1992-1995 distributor plug). But the thin white wire on the 1988-1991 harness goes where the thin white wire on the 1992-1995 harness went. This section needs further revisement for clarity, I will get to this before long...(KEW) To clarify the information on the distributor wiring, match the like color wires at the distributor plugs (for example: org with org) and at the ECU. In other words, the same color wire should go from distributor clear through to the ECU.