whyS0serious

So I'm replacing my 97 engine with the 99 civic ex engine and I'm wondering what stuff do I need.

what I have: complete 99 ex engine, headers, intake manifold, dizzy

What I'm needing: complete 99 ex wire harness uncut, ecu

what else do I need to complete the motor swap

thanks for the help guys! appreciate it

kyden

the 99 ecu and harness won't work, easily. the 99 ecu will definitely throw a code for fuel tank pressure sensor too.

find a 96-98 ex harness, reuse your distributor. or rewire your oem harness.

whyS0serious

how about if i get the 96-98 harness and ecu instead of the 99-00 harness/ecu and just replace the dizzy with the 96-98 ex ecu? will that work?

whyS0serious

Oops my bad u just said use the 96-98 harness lol but if I reuse my dizzy isnt the connector to the dizzy different?

Project Dad

knock sensor needs to be 96-98. plug is different on 99-00

whyS0serious

So 96-98 civic ex harness is the best rout to go and wont have any missing plugs?

just making sure! thanks and much appreciate for the help!

rhymeshark916

Make sure to wire in the secondary o2 sensor directly to the ECU.

whyS0serious

the 96-98 wire harness doesn't have the plug for the secondary o2 sensor?

I just bought a 96-98 civic ex wire harness right now and I'll be getting the 96-98 civic ex ecu to match the harness ...

do i STILL have to rewire the secondary o2 sensor to the ecu???

Project Dad

Yes, an EX car has the secondary o2 wires routed through the cabin floor harness from directly under the heater core box

whyS0serious

ok thanks for the info!! btw...

I've done a 96-98 power windows/door/mirror conversion too with the 96-98 ex floor harness

does the o2 sensor connect to the FLOOR harness or the CABIN harness? i know u said CABIN FLOOR harness but they're two different so I'm just making sure thanks!

whyS0serious

ok i just found out its the CABIN wire harness...

if i were to get the cabin wire harness would it just be plug and play?? or do i have to get the whole dash harness? thanks!

HondaPartsHero

https://honda-tech.com/forums/honda-civic-del-sol-1992-2000-1/how-wiring-secondary-o2-sensor-directly-ecu-2509133/

whyS0serious

Thats where i found out if it was the floor or cabin harness!

my second question is... if the cabin harness is the whole dash harness and is it hard to replace or?

cause I'll be going to the junk yard and get one since I saw an 96-98 ex inside clean dash hasn't been touch yet ...

(don't as me why not just wire the o2 sensor to the ecu i guess i want the car to be 100% oem status)

whyS0serious

Hold up.... I been seeing different post saying its from the floor and some saying cabin.. Is the secondary 02 sensor conneted with the floor harness that is you used for the power windows door locks and mirrors??? If that's the case Ive done that conversion(96-98 civic ex) since my hatch is a 97

If I were to do a 99-00 civic then I would have to change the cabin harness correct???

Let me know ASAP so I don't go to the junk yard and waste my time taking out the cabin harness and taking my car apart

Much appreciated!!

kyden

the secondary o2 plug is part of the cabin harness. not sure why you would go through the trouble of doing that for 4 wires.

Project Dad

I agree. I have a wrecked '00 and I plan on just taking out the wires from the harness to put in my '96 and wire them to the ecu plug.

(just my opinion) The only thing I see desirable from the 99-00 is the front end but even then I wouldn't want to mess with it. (statment excludes the B16A2)

whyS0serious

haha I check it out yeah now i agree with you both... just wiring it up with be easiest way... thanks for the help project! big appreciation to u

whyS0serious

while reading this page everybody is asking if they splice the wires or depin the wires and nobody answered the question...

so I'm hoping to hear from u project... should i t tap the wires to the wires already connected to the ecu?

Project Dad

I personally will be depinning the current o2 wires, taping them and putting dielectric greese in the current secondary o2 plug (to keep from corroding). Then I will install the wires from an ex and pin them to the ecu connector. I have not removed the wires from the ex yet so I do not know what the 12v source is for the 2nd black wire that thread referrs to. I think this route will be the cleranest install, but I will let you know when I tackle it. Should be within the next 2 weeks.

As for soldering o2 wires. The wires are not copper like all other wiring. Mine were stainless steel and solder will run off very easily. I made an extension out of 2 o2 sensors. I got a good mesh on the wires then soldered them, should have welded lol. It was a PITA, should have just bought an extension but money and time was tight.

I help as much as I can. My Honda experience is only a year old, but I have done alot of research and tearing down and rebuilding a 96 coupe in 3 months with no previous knowledge. I have been turning wrenches for decades military and personnal along with a couple of electronics degree's. LOL also grew up in Mopar/hot rod family on a farm.

whyS0serious

hey project here is a better website about wiring the secondary o2

http://ff-squad.com/wp/?p=395

Project Dad

nice find. beats me having to trace the wires. I have also been thinking about unwrapping the harness and pulling the wires for the 2nd o2 through the cabin to the plug.

whyS0serious

ok so now.. im getting a code... P0453

FTP...

do i have to change the whole fuel tank or can i just change the fuel pump since i already have the 96-98 civic ex floor harness in my car

HondaPartsHero

http://www.ff-squad.com/technet/code91.htm

whyS0serious

hey thanks hondapartshero for the website and the other website you listed above

but i was thinking of finding a 96-98 civic at the junk yard and try to find the fuel pump with the sensor on it and swapping it to my tank.. will that work? or it wont? thanks for all your guys help!

kyden

there's nothing different about the pumps. it's the tank itself that is completely different.