MadScientistGuy

I bought this CRX a few months ago, with a b20b swap. It ran fine, pulled hard, never had any major problems out of it. When I went to pull the carpet back, I found the mother of all wiring nightmares. At least in my experience. The car has a Rywire obd1 vtec harness, with a jdm b20b, on a pr4 ecu. There is also an obd1-obd0 jumper harness in that mess. I need to sort through this wiring bunch and try to clean things up and figure out what goes where and all that. I have looked up some wiring diagrams and have not been able to make sense of a lot of it. I am proficient at wiring so once I get locations and all that sorted out, I won't have a problem doing the work to get it right. I am just simply frustrated to no end with the lack or organization right now I can't see straight. So I'm taking a break from it for a few and seeking help from any guru on good ole Honda Tech who would be willing/able to explain to me where some of these wires/harnesses are coming from and going.

Apologies for the long introduction, but I'm trying to explain everything I can to the best detail that I can. If anyone requires any more information I'd be happy to divulge. I don't have the most sophisticated tools out there so my methods are slightly more neanderthal than some.

Thanks guys.

I'll try to explain this as best I can.

The first picture is the overall mess I'm dealing with.

The second picture is of the main Rywire harness coming into the cabin, that plugs into the OBD1 ECU. The code on the ECU is 37820-PR4-A11. The large harness to the right of the ECU goes multiple places, but has a brown/white wire coming off and going nowhere. There are yellow and green wires going into other places in the harness. As you can see the harness above the ECU is blocked off, not sure what it is/does.

The third picture is of most of the wires coming off the large harness from Picture 2. It splits off into two harnesses, the one in my hand that plugs in to a stock harness, I don't know what it is, and another small harness that runs under the drivers side, two green and one yellow wire, and runs back into the cabin harness. Also don't know what those are for.

There are five oem connectors that are not plugged in to anything. Those are the fourth, fifth, sixth, seventh, and eighth pictures.

The ninth and tenth pictures are from what appear to be the conversion harness. The ninth picture depicts a two connector harness, of which only one connector is plugged in. The open slot for that will accommodate the harness from the eighth picture. The "for off road use only" harness from the tenth picture will accommodate the harness from the seventh picture.

The fourth, fifth, and sixth pictures I believe are the shock tower connectors and what may appear to be the map or tps plug. Not positive.

There are white and black wires that don't appear to go to anything. I believe these are the "spares" the Rywire harness includes for additional sensor installations. There is another small connector, around 10 pins, that half of the wires run to nothing, and the other half run back in to the harness. I can't really tell what all is left of the stock harness, but hopefully someone can make some sense of this and possibly guide me to fixing this.

radex7

Some of these should be in the engine bay, does it mean you have a wire tuck? Could you take a shot of the engine bay as well? You said it ran fine. Is there anything that doesn't work?

asianflava

That is the biggest reason why I don't buy somebody elses "project". I just don't trust anybody, there are so many hacks out there. Good luck!

MadScientistGuy

Yes this is the Rywire full wire tuck engine harness. The car ran fine for a while, then it just jumped time and won't start now that I corrected the timing. But I'm more worried about fixing the wiring so that everything is where it should be. Here is a current picture of the engine bay. I have done a lot of work to the car since I bought it, all for the better. But seeing this wiring BS has me pretty stumped.

It's just complicated because it's an OBD2 motor on an OBD1 harness in an OBD0 car. Lots of retrofitting.

4drEF

If it ran before you jumped time, then I'm not following why you are looking at the wiring.
Sounds like you either have a damaged engine or your timing belt still isn't on right.

Anyway....
It looks to me that you have an OBD0 engine harness going to a OBD0-OBD1 jumper and then into ??? some OBD1 Rywire harness.
Maybe the previous owner got a tuck harness for an OBD1 car and realized they messed up so they just made it worse and converted to use the OBD0 engine harness.
yikes!

IF this is the case, the best advice I can give you is to get an unmolested OBD0 engine harness and start working backwards to bring it back to stock wiring + OBD0 to OBD1 jumper.

If you are good with wiring, then you do have another option here. You have everything you need right there to make a very clean harness. Start tracing where those cut wires go. They might not be needed at all. Then cut out all the spare wires and extra lengths. Since it's a tuck harness, you can eliminate a lot of those connectors by soldering wire to wire. Get rid of those butt connectors... clearly not installed well and open to the elements and breakage. You can also delete a few of those connectors because the emissions stuff has been removed (like the charcoal canister)

You have a nightmare there.

7figureswagger

hooooolyyyyy ****, first thats a f*ked up mess....... Makes me feel better about my mess hahaha

on a lighter note, nice f*ckin engine bro, very clean, I wondered if the b20 fit nicely, looks like it went in nicely, still got working room!

sorry i couldnt be more of a help just had to say that because i thought mine was bad, Im sure a few people on here are in the same boat as us tho

MadScientistGuy

I am lead to believe the engine is damaged, so I have another one going in this weekend. But I figured before/during this swap, I would take everything and make it right since the engine will be out, it'll give me much more room in the engine bay to work with. But most of the work will be done inside the car, so that's not entirely relevant.

The Rywire harness is the obd1 vtec tucked harness. It looks to me through all the mess that the obd0-obd1 jumper isn't attached to anything, no ecu, and only one connector is plugged in to the obd0 side. So what I believe happened is the car was running a stock obd0 harness and was converted using the jumper harness to obd1. Afterwards someone bought a Rywire harness and spliced it in to the jumper mess, creating another mess altogether.

I want to keep the Rywire harness in there, if I can. I will be quite upset having to get rid of an 800$ harness because of an incompatibility issue. But I am adequate at wiring so I feel with the right information I can make this work and work right. So realistically, IMO, getting an obd0 harness won't be necessary.

Your second option seems more up my alley. However, tracing wires in a car like this can be tricky. That's the only reason I was attempting to source some help in telling me where some of these wires are coming from. I've never really dug into engine/chassis harness modification just yet, so knowing what goes where from the factory will help a great deal in me pinpointing and correcting these wiring mistakes. I've done multiple engine bay wire tucks so I completely understand doing wiring properly, and this is by far not a good example.

I feel a plan of action as of now is to install the new engine and at least make sure it runs ok. Afterwards, I will break the wiring down, figure out what goes where, and start removing and correcting wiring mistakes until everything is cleaned up and the motor is still running strong.

I indeed have a nightmare, and appreciate the input thus far more than you know. I should be swapping the motor today so granted it runs like it should, I will report back here with progress notes and further input. Thanks a lot guys.

4drEF

Ahhh - ok.
So if what you are saying is right, you can actually run an OBD1 engine harness rather than a modified OBD0 engine harness.
An OBD1 engine harness does not plug into an OBD0 dash/ECU harness so maybe that explains the strange wiring. To make your dash components work and supply your ECU with power and other signals that the dash harness provides, then maybe all the splicing was do to make that work.

RPM_69

I have an 89 CRX and had a shop do the Rywire harness to my b18c1. In short with a different engine, going OBD0 to OBD1, and the Rywire harness needing some of the shock tower wires pulled inside I got a huge mess. Not unlike yours. No RPM sensor, knock sensor, removed the resistor box for the injectors, no A/C, etc. - You wind up with a bunch of plugs and wires that go nowhere.

I have since removed some wires, shortened a bunch of wires, bought some molex connectors at Fry's to make a few of my own connectors and removed a few unneeded plugs. Plenty of online info to help you out, but just spend some time tracing what's connected and what's not needed and you can probably cut that mess in half (or less). It is a HUGE PITA.

EDIT: adding pics.

pic1: my wire mess
pic2: At least she's pretty on the outside

MadScientistGuy

That is what I plan to do. And that makes a lot of sense. But if I can translate what the Rywire harness is supposed to plug into in regards to a factory obd1 harness I can in a sense perform a conversion to adapt those connections to work on an obd0 harness. Again this is why I need to know what goes where before I start any modifications. The motor is out of the car right now I should be putting the new one in tomorrow morning. Once that's done and I can get the car running I'll start tracing wires.

If anyone knows where I could find specifics as to what the new harness is supposed to splice into on an obd1 harness and what harnesses or wires or anything in regards to those corresponding locations so I can attempt to bypass a jumper harness and make my own conversion, pant, that would be helpful. I'm stressed for time so my search capabilities are very limited. Appreciate the help so far all. Hopefully I'll have this straightened out soon.