Ok guys... looking for some help here... searched on this topic a ton, and couldn't find any good information - seemed to confuse me more and more... so i apologize if this has already been covered.


Vehicle: 1991 Honda CRX
Engine: D16Z6 (using OBD0 a6 intake/injectors/wiring harness)


Trying to finish up this OBD-0 to OBD-1 conversion but I have a few wires that are left over, and really confused on where to run them....

Using the Empyrean OBD-o to OBD-1 harness (https://uneeksupply.3dcartstores.com...manual%203.pdf)

Wires Left:

PG1 - Power Ground (Black)

IGP1 - Power Ground (Pink)

Logic Ground (Brown)

LG2 - Logic Ground (VTEC Press) (Black) <-- I have this one grounded to unibody under-dash. and I have the black wire off the press switch plug grounded at the VTEC solenoid.



Hoping someone can shed some light on where to run these wires... the more searching I do, the more different answers I find... Throwing my hands in the air and asking for help! lol






Also, does anyone have a pinout of the stock O2 plug (which wires are power, ground, heater, etc.)... Still have to finish that part of the conversion as well ;-).

 

Very strange they are left hanging outside the harness.
Hook them up to the correlating OBD0 pin.

OBD1 Pin A23, B1, A26, B2
OBD0 Pin A2, A15, A18, A16

All of them are ground except for the B1.
This goes to the main relay connection 3 (marked '86' on the relay) and is a yellow wire with black stripe - this wire also runs to the resistor box/injectors.

 

Yeah, I thought so as well....

I guess Im still a bit confused with your reply. I don't follow what you mean by "hook them up to the correlating obd0 pin"...?

Which wires do I run to what locations? Sorry, I just dont understand what you are trying to say in your response.

Thanks...

 

Based on what you're saying, Im just guessing here, but it sounds like I need to run the PINK (igp1) to the 86 connection at the main relay. Correct??

And for the other wires? All grounds, or...?

 

Anyone...?? Would be greatly appreciated.

(this is the harness, in case anyone was wondering)
http://www.uneeksupply.com/OBD0-to-O...-_p_11753.html

 

I used a different conversion harness, but the instructions were just as confusing. I don't think you need to go to the main relay, all your power connections will be available at the ecu or under the dash. The o2 information is out there, I'm looking now for a link or pic on my laptop. Do you have an o2 plug from a newer honda? I cut a pigtail from a newer accord at the junkyard.

 

You have an OBD1 ECU connected to the conversion harness and finally connected to your stock OBD0 ECU plugs.
All of the wring connections already exist on the stock OBD0 plugs.
The conversion harness should be taking care of the wiring for you, but it's not. Cheap conversion harness.

If you route the wires in question to the pins on the OBD0 plugs, then it will be hooked up properly.

OBD1 A23 goes to OBD0 A2
B1 > A15
A26 > A18
B2 > A16

These are the wire colors on the stock harness (most of them are the same for the non-Si models.



And these are the functions of the wires on the stock harness

 

Thank you! In regards to the "cheap harness" ; even the RyWire $105 harness requires the running of these wires... every OBD-0 to OBD-1 conversion harness I've ever seen still has still this 10-12 wire detach harness that requires the running of these wires. If there is one that does not, please post a link for future reference ;-).



So, in conclusion (not being an idiot, just want to be sure...), All I need to do is:

- PINK WIRE (IGP1) = Run to A15 (on OBD-0 ecu harness) ??

- BLACK WIRE (PG1) = Run to A2 (on OBD-0 ecu harness) ??

- BLACK WIRE (LG2) = Run to A16 (on OBD-0 ecu harness) ??

- BROWN WIRE (Logic Ground) = Run to A18 (on OBD-0 ecu harness??


--- That correct, or am I backwards?? Thanks for your patience, and help!!



****ALSO --

FOUND O2 WIRING INFO, IF ANYONE IS INTERESTED - http://www.rywire.com/catalog/images...0to1jumper.gif

 

Yes - those are the correct connections.

I didn't know those harnesses did that! Weird.
I have built my own so I have never dealt with that issue.


The ground wires are ok to just add a lug to and ground out on the chassis near the ECU.
It's the same deal, however the stock harness ground points are out in the engine bay.
You will still need to make sure the grounds exist in the engine bay as well (thermostat housing)?
Maybe grounding the ECU close by helps with a "better" ground sort of like the 'earthing' wire kits.

 

I bought that same conversion harness. The info they give is incorrect. I am at work at the moment, but when I get home I will look at it. I wrote down where everything goes. Everything works good on mine too, after I chased down all the wires.

BTW the color chart they use is boomslangs and not there's. The colors were all wrong on mine.

 

Thank you! I really appreciate it.

Yes, the stock wiring harness is grounded at the thermostat housing as it should be.

I will connect wires as you stated and see if we can get it going!

 

@rico -- YES PLEASE!! THANK YOU!! WOULD BE GREATLY APPRECIATED!!

 

plug n play ease

 

Yeah, I wish we would have chosen a better harness!! =/

 

Are all of the wires you're referring to on the VTEC sub-harness?

I have the RyWire Obd0-Obd1 harness with a B18A1 in a 90 CRX Si and all I did was convert the engine harness as normal and plug the jumper in between the ECU and under dash harness. I didn't have to run any additional wires.

 

That's because you don't have to wire up vtec or a 4 wire O2.

 

Yeah, and the RyWire harness + Subharness makes life a lot easier!! the O2 and vtec wires are taken care of, that was no problem. My confusion lies with these extra wires... igp1, lg2, pg1, & logic ground...

 

Ok guys.... Rewired the harness as we talked (see below). Still no main relay "click"; no "check engine light" at key on. Assuming no power to ECU?

ECU Ground is good.... and here's where I ran the wires...

- PINK WIRE (IGP1) = Ran to A15 (on OBD-0 ecu harness)

- BLACK WIRE (PG1) = Grounded near ecu (tested, good ground)

- BLACK WIRE (LG2) = Grounded near ecu (tested, good ground)

- BROWN WIRE (Logic Ground) = Grounded near ecu (tested, good ground)


Any ideas what I'm doing wrong?? Super frustrating as I'm sure you guys can imagine ;-). Any help/suggestions would be GREATLY APPRECIATED!!

 

Time to trouble shoot the main relay.
Could be ground (this is one of the two lugs that go to the thermostat housing), ignition switch, fuses, or main relay.

 

Everything worked perfectly prior to installing the D16Z6 (lol, i know those are the "famous last words", but seriously haha). There has not been any issue with the main relay. I will go back over the harness grounds, but im 99.99% sure they are all tight because I checked those first...

Stay tuned for an update ;-)




****UPDATE**** -- ECU Ground @ thermostat is good and tight. ohmed it back to the negative terminal - 1.2ohms = good.

****UPDATE**** -- All fuses are good. Ignition switch is good (starter engages with key on - engine start). No click from main relay - appears to be no power to ecu (no initial check engine light on dash at key-on)

 

Anyone know what this wire coming out of the fuse box goes to?? I didn't disconnect it from anything, but its hanging around looking for a home lol...


Any ideas what it is, or where it goes? Don't know if its related to my problem but trying to eliminate ANY possibilities...

 

UPDATE - Plugged in the old OBD-0 PM6 computer back up, and not getting any main relay click with it either... no initial check engine light illuminates either... Now im really confused...

Thoughts??

 

What distributor are you using?

 

Z6 distributor with Rywire obd0 to obd1 conversion harness. But that's not the issue..

Don't believe the ecu is getting powerm. Anyone...???

Rico - do u find that wiring info for this harness as u mentioned?

 

O2 Sensor Wiring
Factory Wiring:
White = O2 Signal (D14)
Green/White = O2 Ground (D22 or other logic ground)
Orange/Black = O2 Heater (A6)
Yellow/Black = O2 Power (A25 or switched +12v)

Aftermarket Wiring
White = O2 Signal (D14)
Green = O2 Ground (D22 or other logic ground)
Black = O2 Heater (A6)
Black = O2 Power (A25 or switched +12v)

If you get an O2 code after using the aftermarket wiring, switch the two blacks around.