OBDO to OBDI convertion

[ECU-MAN]

Disclaimer: The following is provided as a GUIDE ONLY, and neither myself nor Ozhonda take any responsibility for the outcomes of someone else doing the following. You follow these steps at your own risk!


Aim:

Convert an OBDO car to OBDI to run and OBDI ecu to obtain more flexability for your EMS

Required:

- OBDI ECU
- OBDI Distributor to suit your engine
- OBDO to OBDI harness ( Boomslang Fabrications harness used in this DIY available here )
- Soldering Iron and Solder
- Electrical Tape
- 10mm socket and wratchet



In this DIY Ill be converting a OBDO EF8 to OBDI with a P75 ECU and OBDI distributor from an Integra VTiR. So the EF8 is already a VTEC car so I do not need to run wires from the cabin to sensors in the enginebay. see notes made bellow on how to add extra wires if required. this DIY is based on Boomslang Fabrications harness, If you have a different harness Im sure you can use this article to figure out any reqiured wiring. the Dizzy part will still apply.




Steps: 1

- remove the ecu cover, undo the 4 nuts that hold down the big metal plate with a 10mm socket.





- Unplug the original ECU, unplug the 3 connectors A B and C. Firmly press on the notch in the centre of the connector downwards and pull outwards simaltainously. You can use a flat head screw driver to press on the notch, just be gental.






STEP: 2

- Plug in the convertion harness.






STEP: 3

now its time to do the wiring side of it all.


have a look at the below picture of the harness.




the red arrow points to an extra connector and loom ( sub harness ) , these extra wires are picked up from the OBDI connectors side and go to the sensors in the engine bay. they are as followed

- Green VTEC Solenoid
- Pink IAB - Secondry Intake Runners
- Blue VTEC Oil Pressure Switch ( VTP )
- Red Knock sensor

- Yellow O2 Heater 12v
- Orange O2 Heater
- Gray O2 sensor Ground
- White O2 Signal

If you are installing a VTEC engine into a non VTEC chassis then these extra wires are a real good idea, and you run them directly to the engine bay and to the sensors.

If you are converting a VTEC car up to OBDI then these extra wires are a bit of a pain as you have to wire them to the loom near the ECU connectors as they are not already wired stright through.



since this car is already a VTEC car, then we do not need to run wires to the engine bay. All nessasary wires are at the ECU conectors.

here we only need to wire the VTEC solenoid and the Oxygen sensor. I have disabled the remaining sensors in the ROM as they are not required ( see below )

- since the EF8 only has 1 wire O2 sensor I dont need to wire the O2 heater wires ( 3 wires )
- the VTEC Pressure Switch ( VTP ) is disabled in the ECU so I didnt wire it. ( 1 wire )
- the ECU does not support a knock sensor, so its also disabled in the ROM and no need to wire it. ( 1 wire )
- B16A does not have IAB ( 1 wire )


STEP: 4 ( for VTEC car )

wiring for EF8/9 or any OBDO VTEC car. ( use the picture bellow to help identify the the ECU connector and Pin )

- run the Green wire from the harness to A8 of the car loom, A8 is a Green/White wire
- run the white wire from the harness to C16 of the car loom, C16 is a white wire with silver dots

Optional

- run the blue wire from the harness to B5 of the car loom, B5 is a blue/black wire
- run the blue wire from the harness to B19 of the car loom, B19 is a white wire with silver dots

if you are running a 4 wire Heated O2 Sensor then

- run the yellow wire to the black wire on the 4 wire O2 sensor
- run the Orange wire to the other black wire on the 4 wire O2 sensor
- run the gray wire to the green or gray wire on the 4 wire O2 sensor
- you can use the exsisting wire from the car harness and connect it to the white wire of the 4 wire O2 sensor


Proceede to Step: 6











STEP: 5 ( for non VTEC cars )


- run the Green wire to the VTEC Spool Solenoid on the engine
- run the Pink wire to the 2 pin IAB solenoid valve connector, the other yellow/black wire on the 2 pin IAB connector needs to be wired to a switched 12v source ( you can find this on the EACV )
- run the red wire to the Knock Sensor under the inlet manifold
- run the yellow wire to the black wire to the 4 wire O2 sensor
- run the Orange wire to the other black wire to the 4 wire O2 sensor
- run the gray wire to the green or gray wire to the 4 wire O2 sensor
- run the white to the white wire of the 4 wire O2 sensor


STEP: 6

time to remove the existing distributor





- Unplug the two connectors for the distributor, ( Green arrows in above pic )
- unplug the leads
- undo the 3 bolts bolts shown by the red arrows above that hold the distributor on and remove the distributor.

place both distributors on a bench





STEP: 7 ( Pay attention here or you will be sorry )

Time to remove the OBDO connector from the OBDO distributor. Looking at the pic bellow, you have to de-pin the OBDO connector from the distributor. To do this you have to use a long pin and push the tab that the red arrow is pointing at upwards, while pulling on the wire at the back of the connector.







- mark the ICM wire ( Pin 7 in the pic bellow ) so you do not mix it up with the other white wire.







- Remove all other pins from the connector. Now the ODBO connector is free from the OBDO dizzy.

- do the same for the power and tacho connector. take note of the pin orientation of the blue wire and the black/yellow wire.



STEP: 8 ( dont mess this part up )

Time to do the same for the OBDI distributor, only this time as we de-pin a wire we will plug it straight into the OBDO Connector.


- Start by removing the white part inside the greay conector, get a grip on it with long nose pliers and pull it out.






- to de-pin the OBDI connector with a pin push up and out on the pin ( red arrow ) with the connector facing you as shown in the bellow pic. You can also pull on the wire on the back of the connector to assist.





- using the bellow diagrams start with the ICM from pin 7 of the ODBI conector, plug it into pin 7 of the OBDO connector

- unplug pin 1 from the OBD1 connector and plug it into Pin 4 of the OBDO Connector
- unplug pin 2 from the OBD1 connector and plug it into Pin 3 of the OBDO Connector

- unplug pin 3 from the OBD1 connector and plug it into Pin 6 of the OBDO Connector
- unplug pin 4 from the OBD1 connector and plug it into Pin 5 of the OBDO Connector

- unplug pin 5 from the OBD1 connector and plug it into Pin 2 of the OBDO Connector
- unplug pin 6 from the OBD1 connector and plug it into Pin 1 of the OBDO Connector




















STEP: 9


We now have to swap the conectors over shown in the red circles. de-pin the connectors. I cut off the spade connectors from the OBDO dizzy and soldered them onto the wires of the OBDI dizzy as they where different and would not fit in the OBDO connector











make sure the 2nd connector is wired correctly








STEP: 10




- Fit the OBDI Distributor to the car. Leave the 3 bolts finger tight so you can set the timing later.






be sure to get the firing order right or you will have lots of fun. ( 1342 )


STEP: 11

fit the OBDI ECU to the harness and make sure everything is all plugged in. For this car I used Crome and a stock 203 ROM for an OBDI JDM B16A. You can use Crome to disable knock, eld, o2 heater, ect







STEP: 12

- Time to start the car, If everything is wired correctly then she will fire 1st pop.

- make sure the engine light goes out when the engine starts and it should not come on at all while the engine is running.

***** If the Engine Check Light comes on after you start the car turn the Engine off refer to step 13 *****

- Allow the engine to run untill the engine warms up. Thermo fans should at least come on twice.

- Find the old blue 2 pin timing set connector under the LHS of the dash near the heater fan blower and bridge it. This connector is now the SCS connector for OBDI diag and adjustment.

- Use a timing Light and Set the Ignition base timing.

- tighten the distributor bolts, and recheck the timing.

- remove the bridge from the SCS connector


Thats It, road test the car safly with out braking any road rules . Make sure VTEC engages. After a nice drive check the ECU again for codes. You should have no codes in the ECU.


STEP: 13


If the Engine Check Light Comes on or does not go out when you turn on the Ignition or start the car, you may have miswired something. It would be best to check the ECU for fault codes.

With this harness the old timing short connector becomes the SCS connector. On an EF8 and EF9 you can find it under the pasangers floor well, near the heater fan blower. Bridge it with a paper clip and read the fault codes out. Its a good point in the right direction to where you messed up. Go back and rectify the problem. IF your unsure post your codes here. Im sure I or others will be able to help you.





Final Notes:


This convertion will only work on OBDO cars that have non Vacuum advanced Distributors. Older cars that have vac advanced distributors are pre OBDO and although they have the same ecu connectors they are wired differently.


Big Thanks to

SirFeoc for his help and his car for the DIY
Edgeauto for supplying the Harness, ECU and Distributor and his help.



Disclaimer: The following is provided as a GUIDE ONLY, and neither myself nor Ozhonda take any responsibility for the outcomes of someone else doing the following. You follow these steps at your own risk!

[ACTI0NMAN-1]

if using a chipped p28 obd1 ecu be sure to disable knock sensor in <crome> as the p28 does not use a knock sensor.

[stanleym]

doin this 2moro cheers ecu-man

[Edgeauto]

You own the DIY section

[ECU-MAN]

doin this 2moro cheers ecu-man

good luck with it,

post here if you have any questions

[Dxs]

wouldnt it be better to get some obd1 plugs for the loom to the dizzy, so that if you ever need to replace the dizzy you dont have to repin it again?

also did the dizzy bolt up ok? I heard that they often dont?

[barefootbonzai]

can i ask y you had to change the wiring of the dizzy? Wouldn't it have been fine just leaving it as is?

[stanleym]

you would still need to re-pin the loom if eva u changed the engine again etc. fair comment that dizzy would be changed more than the engine but ones u kno how to do it it only takes 5-10 mins not all that hard....

the reason u need to change the dizzy was because each wire goes and controls different functions to the dizzy and ecu etc. if left how it was it engine codes would be apearing etc etc im sure ecuman can extend on this
and also plugs are different..

**finished doin the change**

wasn't all that hard realli

mainly the dizzy was the worst but using the harness from edge automotive and the ecu that ecuman provided me was able to wire it reasonably easily

1 question though ecu-man .. during the install i found out that the o2 sensor only had the one cable running to it, instead of the 4 wire o2 sensor (that i should have bought:P) but i wired the (white) o2signal wire to it from the ecu/harness will that be fine or should i do the +12v ground and heater wires??

another thing was the oil pressure switch wires weren't the colours that i had been given in the write up from edge automotive
the 2 pin socket had colours of green/blue? and red/yellow? or something i kno one was ground but no tsure which one it was and didn't have multimeter to test it...

ill let u kno if the engine starts when they finish on the motor

but once again many many thanks goes to

edge automotive and ecu-man for all the help they have given to get the ecu fixed etc

[ACTI0NMAN-1]

if the new ecu uses a 4 wire o2 you dont need to connect or use the old single wire o2. If you used a conversion harness it should have the 4wires for the 4wireO2 listed.

[stanleym]

ye ai kno that but i had forgotten to get myself the o2 sensor with the 4 wires so for the mean time i connected just the o2 signal wire

[ECU-MAN]

single wire o2 will work just fine you wont need to het a 4 wire one.

also with that ecu I setup for you, you dont need to wire the VTEC Pressure Switch

[ECU-MAN]

wouldnt it be better to get some obd1 plugs for the loom to the dizzy, so that if you ever need to replace the dizzy you dont have to repin it again?

also did the dizzy bolt up ok? I heard that they often dont?

If you can get hands on then it would be better, However you already have the connectors nessasary to do the job.

DC2 dizzy worked well