I was curious about all the wiring, I have an 1990 Si HB and I'm swapping in a b18c1 I just got. But I thought all I had to do was get the efsi-vtec sub-harness, cause thats what I was told to do when I was gonna do a b16a swap, and I figured it would be the same cause they are both obd1. But I'm really confused on what to buy for wiring after I keep reading different websites on how to do it. I plan on a buying a P72 GSR Manual ECU OBD1 for the motor but not sure what else is needed to complete all this wiring ****. Someone help me out please and ease my mind.

 

When you recieve a stolen motor, you generally don't get any wiring instructions... so you'll need an OBD1 conversion. I'd recomend the Boomslang harness, and you'll need the HASport Hydro mount kit. As far as anything else, make sure you shave the block # and tranny code off of the motor ASAP.

 

What the hell is the boomslang harness? And if I get the conversion from obdo to obd1, I'll still need the efsi-vtec subharness for the engine right?

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by red_honda_racer &raquo;</TD></TR><TR><TD CLASS="quote">What the hell is the boomslang harness? And if I get the conversion from obdo to obd1, I'll still need the efsi-vtec subharness for the engine right?</TD></TR></TABLE>

boomslang is one of the members on here (it's his SN).

https://honda-tech.com/zerothread?id=844928

Depending on who you go through, some people will modify your engine harness with whatever plugs your motor has. They can also make up a seperate VTEC subharness or integrate it into your cutom engine harness. The OBD conversion harness plugs the OBD 1 (or 2) ECU into your Civic or CRXs OBD 0 firewall plugs.

did that make sense?

EDIT: I got my custom engine harness, VTEC subharness and OBD0 to OBD1 conversion harness from nikitad here on H-T. droppedcrxsi also does wiring work if you dont want to do your or if you feel it is over your head.

 

Yeah I'm getting closer, I got the ecu part figured out now. But the thing is I have no engine harness at all to work with and I want to run all obd1. I thought the sub-harness would be my actualy engine harness cause I haven't seen otherwise. And Hasport onlys carries the ONE harness for the Si's, while everything else is for the dx's and etc.

 

You'll need an Si engine harness.

 

do you guys know what the actual sub-harness replaces? I mean like is it from the fuse box to somethig else.. and now I'm wishing I wouldn't of sold my si engine harness.

 

Are you talking about the HASport four wire conversion?

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by red_honda_racer &raquo;</TD></TR><TR><TD CLASS="quote">Yeah I'm getting closer, I got the ecu part figured out now. But the thing is I have no engine harness at all to work with and I want to run all obd1. I thought the sub-harness would be my actualy engine harness cause I haven't seen otherwise. And Hasport onlys carries the ONE harness for the Si's, while everything else is for the dx's and etc.</TD></TR></TABLE>

You can look around the classifieds forum or at your local junkyard to find an engine harness. You'll need an Si engine harness, since you dont have one, and you'll also need a GSR harness to get your plugs from. Then you can do it yourself or send it to somebody to solder in the correct plugs you'll need. Then you have to get the OBD conversion harness, and a VTEC subharness.

Like I said though, I bought all that stuff from nikitad. He did all the de-oinning, soldering and he integrated the VTEC subharness into the main engine harness. So all I have to do is plug the OBD conversion harness up and hook up the engine harness up to the various engine components.

Anyways, if you need some help in that area contact nikitad or droppedcrxsi. They can help you out. Also I've included some pics of the engine harness, OBD conversion harness and VTEC subharness, just incase you are unsure of what they look like.

CUSTOM CRX ENGINE HARNESS WITH B16A PLUGS AND INTEGRATED VTEC SUBHARNESS


OBD 0 TO OBD 1 CONVERSION HARNESS


STANDALONE VTEC SUBHARNESS


pics courtesy of boomslang and tjshonda site

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by red_honda_racer &raquo;</TD></TR><TR><TD CLASS="quote">do you guys know what the actual sub-harness replaces? I mean like is it from the fuse box to somethig else.. and now I'm wishing I wouldn't of sold my si engine harness.</TD></TR></TABLE>

The VTEC subharness adds wiring between the ECU and the folowing parts:

Knock Sensor
VTEC solenoid
VTEC Oil Pressure
ground

And if you have a B16 you'll need a wire for the 2nd O2 sensor. And if you have an OEM B18C1 intake manifold, I think you'll need wiring for the IAB too.

 

Can't I just get the b18c or b16 harness and hook that up to the engine, instead of having to buy the si harness as well? I hate to keep asking questions but I just want to make sure I know what to get and do so I don't screw myself over. And will the conversion from obdo to obd1 allow me to run the P72 GSR ECU?

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by red_honda_racer &raquo;</TD></TR><TR><TD CLASS="quote">Can't I just get the b18c harness and hook that up to the engine, instead of having to buy the si harness as well?</TD></TR></TABLE>

No, because the B18C engine harness will not plug into your 90 Civic factory chassis or firewall plugs. A 90 Si harness will plug directly into your firewall or chassis plugs but it wont plug directly into the engine. This is where you have to replace or re-pin the Si engine plugs with the B18C engine plugs.

If you supply your own Si harness to nikitad may be able to provide the B18C plugs. That way you dont have to buy an entire 94-95 GSR harness.

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by red_honda_racer &raquo;</TD></TR><TR><TD CLASS="quote">I hate to keep asking questions but I just want to make sure I know what to get and do so I don't screw myself over. And will the conversion from obdo to obd1 allow me to run the P72 GSR ECU?</TD></TR></TABLE>

Yes, the OBD conversion harness is what plugs into the ECU and to the firewall ECU plugs in the passenger compartment. With all this wiring and re-wiring of the engine harness and with the OBD conversion harness, one thing you'll have to know is how to match up the correct ECU pin with the correct wire on the engine harness and OBD harness.

Moving the pins around is what kept confusing me. So that's why I had nikitad do it for me. If you are gonnna be doing this yourself, I think you'll wanna study ECU pinouts for a 90 Si and an OBD 1 P72. Because you have to make sure that the wiring between the ECU pinout and the part it goes to on the engine is correct.

With that I cannot help you though

 

Sweet. Thanx alot guys. I really appreciate the help you have given me. I'll let you know how it goes.

 

Ard performance carries a bunch of different wiring harness's and conversions.

http://www.ardperformance.com/...l=230

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by red_honda_racer &raquo;</TD></TR><TR><TD CLASS="quote">Ard performance carries a bunch of different wiring harness's and conversions.

http://www.ardperformance.com/...l=230</TD></TR></TABLE>

I just looked at some of the pricing and unless I am mistaken that stuff looks way overpriced. The OBD conversion harness is ~$115, but the custom engine harness B16's and B18C's swaps is ~$450!

I paid less no more then $280 for my OBD conversion harness, custom engine harness, and VTEC subharness.

 

Since i didnt see it asked.....Do you have your stock engines wiring harness?
If so then all you need to do is get the subharness and the boomslang jumper conversion.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by hahagasdcrx &raquo;</TD></TR><TR><TD CLASS="quote">Since i didnt see it asked.....Do you have your stock engines wiring harness?
If so then all you need to do is get the subharness and the boomslang jumper conversion. </TD></TR></TABLE>

He already mentioned previously that he didn't have a stock harness to work with.