OBD conversion inquiries

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91REXsi

New Member
I'm swapping a jdm D15b vtec into my si crx. I bought a P-08 ECU and an the OBD 0- OBD 1 conversion kit from rywire. I just had a few questions about the wiring.

I've read this
http://www.rywire.com/store/images/instructions/inst_0to1jumper.gif
but these questions remain.

1)I understand that the D15b uses a 1-wire oxygen sensor. where does this hook into the harness? the conversion kit is set up for a 4-wire o2 sensor.

2)Could someone explain in some more detail or link me to an explanation of how to rig the check engine light? the article says something about adding a toggle switch?

3)Injectors... the way I understand it is that I can use my old OBD - 0 injectors. This seems like much less work than converting the plugs and whatnot. Is there any advantage to converting to OBD - 1 injectors? do I need to buy anything extra to do this? links or suggestions welcome.

Thats it for now, but I may have more questions as things progress.

thanks
 
1.) The D15B VTEC should use a 4-wire O2, as it's a OBD1 engine. I know that the 88-91 uses 1-wire.

2.) Not sure

4.) As long as you keep the resistor box, it'll work fine. The only advantage to swapping to OBD1 injectors is it gets rid of the resistor box.
 
#2. Pin B6 at your ECU, clip wire, add extension and wire bulb or switch in the circuit, that way you can see your code flashes.
 
I'm 99% sure that the jdm d15b is a 1 wire o2 sensor...

Blackice... srry for my noobish tendencies, but i'm a little unclear about your explanation. Does pin B6 go tho the check engine light on the dash? if so why would it need a toggle switch? how would you ground said inline light? if the wire goes to the check engine light anyways why would you put a light inline?
https://hondaswap.com/attachments/10d1100714226-obd1.jpg
using this diagram... B6 is the 6th pin over on the top row of 'B' right?

thanks a lot for the responses
 
K2e2vin said:
1.) The D15B VTEC should use a 4-wire O2, as it's a OBD1 engine. I know that the 88-91 uses 1-wire.

2.) Not sure

4.) As long as you keep the resistor box, it'll work fine. The only advantage to swapping to OBD1 injectors is it gets rid of the resistor box.
Click to expand...

yes thats right D15b Vtec have 4 wires 02 D15b2 sohc non vtec has 1 wire 02, i used had D15b Vtec it blow up so i have D16a6 SI non vtec right now
 
91REXsi said:
I'm 99% sure that the jdm d15b is a 1 wire o2 sensor...

Blackice... srry for my noobish tendencies, but i'm a little unclear about your explanation. Does pin B6 go tho the check engine light on the dash? if so why would it need a toggle switch? how would you ground said inline light? if the wire goes to the check engine light anyways why would you put a light inline?
https://hondaswap.com/attachments/10d1100714226-obd1.jpg
using this diagram... B6 is the 6th pin over on the top row of 'B' right?

thanks a lot for the responses
Click to expand...

All obd1=4 wire O2

OBD0- flashes error code on the ECU.
OBD1 cars- flashes error codes via CEL on the dash...but there is a connetor on the car that has to be jump to get it to flash.

Your car, being OBD0, will not ahve that connector. So what you are doing is grounding that circuit out and putting a bulb there so you can see what codes flash.

OBD0 the circuit is just straight from the light to the ecu, if Im correct from research, you putting th light there just let the flashes be visible, if you understand what I mean. I will go look at the pin out chart of a OBD1 ecu and see if the circuitry is any different from a OBD0 besides the connector.

All you should have to do is install that bulb but I will double check for you.

+1 for smart questions and learning;)
 
91REXsi said:
using this diagram... B6 is the 6th pin over on the top row of 'B' right?

thanks a lot for the responses
Click to expand...



hell no, thats either or 13. even on one row, odd on next row.
6 was 3rd over on bottom row.

Im sorry, B6 is the CEl on OBD0, A13 is the CEl for OBD1
https://hondaswap.com/reference-materials/ecu-pinouts-28667/


Look, your CRX Si is already MPFI. All you have to do is
1. swap engine
2. Use your STOCK Si harness, not the one from the D15
3. install or use existing 4 wire 02
4. At the ECU, install sub harness.
5. Install ECU into sub-harness.
6. Run sub harness through the firewall to engine bay
7. Plug in Distributor to the adapter, adapter to sub harness
8. The little 4 pin female grey plug thats left, plug in 4 wire O2 sensor
9. Plug Madd TyT3 VtAkk wires from sub harness to the vtec soleniod and pressure switch.

thats it.

even if the motor dont come with a 4 wire O2, buy one and use it instead
 
Still a little bit unclear, but I think I have enough of a grasp to get things started. I'll let you know how things go after this weekend. Thanks for the helpful input, so many people are quick to jump on the "STFU N00B" bandwagon. Its refreshing to deal with patient people.
 
91REXsi said:
I'm swapping a jdm D15b vtec into my si crx. I bought a P-08 ECU and an the OBD 0- OBD 1 conversion kit from rywire. I just had a few questions about the wiring.

I've read this
http://www.rywire.com/store/images/instructions/inst_0to1jumper.gif
but these questions remain.

1)I understand that the D15b uses a 1-wire oxygen sensor. where does this hook into the harness? the conversion kit is set up for a 4-wire o2 sensor.

2)Could someone explain in some more detail or link me to an explanation of how to rig the check engine light? the article says something about adding a toggle switch?

3)Injectors... the way I understand it is that I can use my old OBD - 0 injectors. This seems like much less work than converting the plugs and whatnot. Is there any advantage to converting to OBD - 1 injectors? do I need to buy anything extra to do this? links or suggestions welcome.

Thats it for now, but I may have more questions as things progress.

thanks
Click to expand...


1. To do this you would need the engine harness fron any 92-95 car that comes with vtec. It will have the four wires for the new o2. all you have to do is solder all the 4 wires.

2. The ecu jumper comes with a set of wires that you can solder to the toggle switch that will make the dash lights go on and off those are the codes that the ecu throws out so you can know what needs to be service.

3. If you use the injectors from the 92-95 car you wont need the injector resistor box. All you would need is to take the injector wires from the new engine harness and solder it to your car's wire harness.

I did my own convertion, this swap its really easy take your time when soldering all the wires so you wont mess anything up.
 

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so i got my motor on friday, but i have to wait till next weekend to swap it in :(. It is a 1-wire o2 sensor afterall... I assume I just hook this to the signal wire on the p-08 ecu? I got my conversion kit from rywire as well and it sort of surprised me, there were no loose wires for me to solder into the check engine light and such. Everything had a plug on it already. I guess i'll just plug everything in and see what happens, but i'm sure I'll have a few questions. so stand by.
 
Who did you buy your motor from? I know for a fact that the D15B VTEC has a 4-wire. The P08, the ECU used with the D15B VTEC, looks for a heater.

You can hook it up and make it work but you'll most likely get a code for O2 heater.
 
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Sounds like the manifold got swapped or something. Either way; just buy a 4-wire O2 or call them up and tell them you got the wrong O2 sensor. Then, just plug it up to the harness.
 
Will it work with the 1-wire just hooked to the o2 signal on the ecu? i'd really rather avoid the hassle and cost of getting a new sensor.
 
another question... a little off topic, but here goes.

when i'm buying parts for my jdm d15b, what car do I list it as being. You know how parts stores require a make, model and year before they will even acknowledge your existence. Do i call it a 92-95 civic ex, dx, vx, lx, ?x... i'm specifically looking for the right oil filter and heater/radiator hoses.
 
91REXsi said:
Will it work with the 1-wire just hooked to the o2 signal on the ecu? i'd really rather avoid the hassle and cost of getting a new sensor.
Click to expand...

You can make it work by putting in a chip to disable o2 heater or use some sort of resistor where the heater should be connected. Ground the O2 ground to the thermostat ground or anywhere near the block(preferably as close as you can get it to the O2 sensor) as the 1-wire O2 uses the engine as a ground.

The D15B VTEC is along the lines of the 92-95 Si/EX. The top end is exactly like the Z6(P08 head casting), minus a Purge valve, and the bottom end is more similar to a D15Z1(92-95 VX). You still use the Z6 parts for stuff like the oil pump and bearings though. For the oil filter just look up 92-95 EX(although most Hondas are the same) and for the hoses just use 88-91 Si(upper may need to be trimmed).
 
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