So I am working on a 1991 civic wagon. When I first bought the car it came a blown b16a. I pulled the engine and sold it, bought a b20b and a brand new rywire obd-1 wiring harness. I thought it was going to be straight plug in play. Until I came across the previous owner wiring hack job. Every individual plug was wired separately, to different spots.

What I have done so far is brought all the plugs back in through the firewall and started taking all the old electrical tape off of them. My Rywire harness plugs into my p28 ecu I bought. The rest of the old plugs are a mess. I am taking the whole dash apart to get a better idea of where everything runs too. I would like to somehow make it all go to one plug than somehow connect to my rywire harness plug.

Where should I start?

 

So I am trying to somehow get my rywire harness to connect to everything in my car. How the previous owner had it set up was he had each plug individually ran than a mass duct tape everywhere. What I started to do was undo all the duct tape, but the wires and everything run in the dash etc and it is very hard to trace them. So I started tearing apart the dash. I got it almost off it seems like it just hanging there, but i still can not remove it.

Anyways back to the wiring. So for my harness the there are 5 plugs on one end than the rest of the other side are all the plugs for the engine harness. The 3/5 plugs on the inside part of the harness plug into my obd-1 ecu. Than another one plugs into the other part of the harness that came with the wiring harness. Than that runs off somewhere else. This is a really big headache for me. I think I will need a manual to get all these wiring diagrams in order. I want to heat-shrink everything and run it into one plug so it will just plug straight in my Rywire harness.

This was the old obd-0 to obd-1 conversion harness that was used before. I will not be needing this I assume this my rywire harness plug right into my ecu.

These were the plugs running into the engine bay. The 4 injectors wires are in there somewhere that were duct tape together to another piece leading to the injectors plugs. When I sold the B16a. It also had some of the engine harness attached to it I believe.


This is how the wiring harness looks plugged into the ecu the 3 plugs go right in the one other plug connects to this other wiring harness leading to two other plugs. Than I have one plug left out of 5 by the ecu.

 

This is how I am trying to get it. I want the rywire to come through the firewall. Than connect the ecu, and the other plugs. Than the rest just plug into my obd-1 converted b20b. So I most like will have to splice all my old plugs into one or two plugs that connect to the harness's I bought from rywire. I don't want to tamper with the rywire harness. It costed me a lot of money.

 

might be easier to purchase an unmolested dash harness. Then everything should be plug and play.

 

Like from a junk yard? Does the harness have to be from within the same year/chassis. Because my wagon has the automatic seat belts. I want those to still work.

 

It would be best from the same year and model. At least start looking for one

 

And look on ebay, there are lots of harnesses on there

 

lets start off with this.
1. what trim is the wagon. there are very few stock mpfi versions out there. im going to assume you have the more common dpfi wagon.
2. the harness you purchased from rywire will only work on stock mpfi set ups, not converted versions mind you. if your body was dpfi you will need to mod the rywire harness to work. or purchase the proper sub harness from them.
3. you will still need to do the needed splicing with the rywire harness (which should be laid out to you in their instructions)
4. rywire is an awesome company im not bad mouthing them in any way with this next statement that I will make, its just my personal opinion:
making a harness with a single wire color is not something I would do. if you think your having a headache now with your current factory harness, imagine trying to diagnose a full harness of 30+ white wires.
5. you can bypass the chassis harness but you would need to take it apart and run a new wire directly to where it ends after leaving the factory ecu plugs.

 

like stated above the best route when dealing with a hacked up harness it starting from scratch with a new one. head to local junkyard and find your matching car. im not sure if its different for wagons but I do know civics and crxs have different body harnesses in respect to years 88-89 and 90-91

 

Okay, I wish rywire gave instructions on what to splice. Are you talking about that one plug with all the white wires coming out of it. Do all those wires have to be spliced with other wires? Is this what you would saying about diagnosing full harness of 30+ wires.

This weekend I am heading to the junkyard to fine a new dash harness. Also my wagon was dpfi than was converted to mpfi.

 

yes. those 8-9 loose wires have to be spliced into your factory ecu plugs. only 1/2 of them are needed to run the car tho. those wires include fuel pump, power, speed sensor, ecu memory, eld and a couple more.

 

post a clearer picture of the loose wires. on one pic looks like there is writing on them or labels for their functions.

 

it also looks like your missing I very vital distribution cap that goes on the 10 pin gray plug. looks like it plugs into something but shouldn't. that cap will most likely be the power supply for the ecu as well as other engine sensors

 

Yes, you are right about those loose wires. I checked them and they say like black green, blue green, and so so on. Each wire has some writing on it.

 

Also sorry what is a distribution cap? Are you talking about that one round plug. That one there had a cap on it which a took off just thinking it was a protecter for the contacts. Or are you talking about the one gray plug with all the loose white wires coming out of it.

 

Yes the cap. You will need to put it back on

 

Okay so I have been trying to do what you said. Splice the 9 wires to the factory ecu plugs. The thing is though the wire codes on the 9 whites wires only match up to some of the wire colors on the factory ecu plugs.

Keep in mind that the car is already converted to mpfi if that changes anything. There was made obd-0 to obd-1 conversion harness made.

If I get these 9 wires wired up, what do I do about the rainder plugs I have like the 4 injectors wires just hanging from one of the stock ecu plugs, there is a o2 sensor plug, etc. Will these just all stay there and be replaced by the Rywire plugs.

 

Would anyone know what the 9 wire color codes on this harness mean?

Green/red
white/blue
yellow/black
white/black
green/blue
brown/white
blue/white
green/orange
orange/black

I tried matching the colors the factory ecu colors because I assumed that is what you are supposed to do. But only a few matched up and the rest never match up at all.