Ok so here's the deal! My name is Justin and I drive a 96 EK dx with a d16y8 swap.

I bought it a little while ago only to realize that the previous owner neglected to swap the ex ecu and engine wiring harness. Stupid I know...

anyways I got the ex ecu and harness off a buddy but ran into the issue while installing the harness that my motor has a three wire IAC while the harness has a two wire IAC.

I've done my research to find out that the two wire is OEM for the civic ex's. So my ultimate question here is how do I go about fixing this issue?? I borrowed a two wire IAC off a buddies single Cam but it doesn't fit in place of the three wire that's there already?? Should I just take his whole intake manifold with the two wire IAC and swap it into my car or what??

 

does your map sensor have 3 or 2 wires?

 

Round plug with two wires

 

Is your car auto or manual?

 

Oops sorry I forgot to include that in the original post! It is a 5 Speed

 

Sounds like you have a auto intake manifold and you have a 5spd harness.
Check the previous harness for splices

 

Thank you so much for all the quick responses and help btw. But I never thew there was a difference between the auto and man as far as intakes manifolds go.

So I can take any other manual obd2a IAC and swap it onto my manifold? Or do I have to get a full manual manifold with all the plugs to make it all run right?

One last question while I'm on here if you happen to know..... do you have any idea what eci plug and pin or color the vtec wire is on the man d16y8 harness?

 

96+ civics have different intake manis for auto or manual ecu's
3 plug iacv/map sensor= Auto intake manifold.
2 plug iacv/map sensor- Manual intake manifold.
As far as bolting up a manual iacv into a auto intake manifold you can't, thats why people who run obd2 and convert their car to manual need to change the intake mani to run right.
My question is how was it running before you tried the ex harness?? Did it have a check engine? Was the harness spliced?

 

it was running the DX ecu and harness (remember the car is a DX) with the Y8 motor. vtec and knock sensor and vtec oil pressure obviously didnt work. idled a little high and rough yet ran good. and yes there was a CEL but when i scanned it, it threw a "speedo" code.

so i looked and your absolutely correct, it is in fact an auto manifold as the map sensor is also a 3 wire.

now i just got ahold of a guy in tennesse that said he has a Y8 manual manifold with a Y7 throttle body on it with the Y7 IAC on the TB and the Y8 IAC on the back of the mani with the map sensor and everything on it for 40 bucks. this should work right? cause if i plug my harness into the correct IAC and leave the wrong IAC unplugged the ecu will never know the difference right??

again thanks so much for all the help!

 

i recently did a swap from a vtec(y8) to non vtec(y7) due to rod bearing failure; both 5spds. i ran into the complete opposite of what you did justin. the 2wire to 3wire can be a pain and vice versa. i swapped the y8 mani onto the y7. had to plug the "air assist holes", dont know what theyre called, and use the tb and injectors from the y7. i had the y8 iacv hooked up first using the y8 harness. i used the y8 harness because i used the y8 exhaust mani as well. anyway... i kept throwing a P1509 code: IACV Failure! DENIED! so i ran 3 separate wires from my y7 ecu to the y7 IACV. using pins, b6(IACV+) b15(IACV-) and b23(IACVcontrol)

BINGO!

car runs fine. had the motor in for probably 3-4 months now no problems. drive it almost 300miles a week total, back and forth to work.

so break it down..
i used y8 exhaust and intake mani
i used y8 harness
i used y7 motor, tb, injectors, tranny, and ecu
i used y8 speed sensor
ran 3 separate wires from pins b6 b15 and b23 to the y7 tb IACV

worked for me


hope this helps anyone

 

hmmm well i got a guy thats sellin me a Y8 IM with Y7 TB with all the sensors attached. meaning there are two IACs. So theoretically im thinking that i can plug my harness to the Y8 IAC on the back of the manifold and just ignore the Y7 IAC thats on the TB and the ecu will never know its there.

so i guess ill find out soon whether itll work or not. hes sellin me it all for 40 bucks tomorrow after work.

 

you need to use the y7 iacv with the y7 ecu im sure. someone correct me if im wrong. but, i was using the y8 iacv located on the intake mani and kept throwing the code. so i disconnected the y8 iacv plug and just let it hang there. then, ran 3 separate wires from the y7 ecu to the y7 iacv located on the tb. all the other sensors, you should not have had to replace..

hope that one you're getting works flawless, let us know

 

bump

 

Ok all 96-00 Civics, with the exception of EX/HX/SI 5 speed, have a 3 wire IACV. So all auto and non VTEC SOHC from these years use the 3 wire IACV. Your best option is to either get a new intake manifold with the two wire style or you can tap the back of your intake manifold for the bolt holes and IACV holes using this thread and use a 5 speed P2P ECU for the Y8:

http://www.d-series.org/forums/engin...c-problem.html

To clear up any misinformation all MAP sensors, at least from 88-01 are 3 wire. The ECU must be matched with the IACV, in this case where a 3 wire or a 2 wire IACV is used. All the following are 3 wire ECU's: P2E (96-00 Y7 ECU), P2P auto (96-00 Y8 auto ECU), P2N auto (96-00 Y5 auto ECU). The only 2 wire ECU is the P2P manual ECU and the P2N manual ECU.

 

 

well ill be running the Y8 ecu and harness so why would i use the Y7 IACV?? wouldnt it make sense to ignore the Y7 IACV there and plug my harness to the Y8 IACV since ill have both there????

 

Theres your correct info right there ^

 

yes however did you actually read my question about the Y7 TB on the Y8 Mani or did you just wanna prove a point that my original question has been answered?? not to be a douche so dont take it the wrong way!! but im just wondering.

my question was not answered in his post (as helpful as it honestly was!) i just dont understand if i can have a Y7 TB and IACV and just ignore the Y7 IACV since i obviously wont need it??

and seriously guys (all of you) thank you for all of the help!

 

reason i say this is because i cant find a Y8 TB to match the manifold i found btw

 

Read over it quickly and never paid much attention honestly.

Don't think so. Its been a while since I looked at a Y7 throttlebody but I don't recall there being a fast idle thermo valve on it. You should be able to run a D15B7 or D16Z6 throttlebody though.

 

ok so i found a different guy about an hour and a half away with the intake manifold and throttle body (both matching 96 civic Y8 parts) with all sensors still attached for only 25 bucks! so im going to pick it up tomorrow in between classes. ill post back tomorrow with updates, thanks guys!

 

r u using the y8 ecu with a y7 motor?

 

the post said that i have a Y8 motor... that particular tidbit that you quoted was when i was talking about having EVERTHING Y8 except the throttle body.

reread the entire post and youll understand, no offense i just dont feel like re typing it all sorry

 

lol sorry. just get an ls tb and smack it on there. pnp. they might be a lil more ready available. you might have to dremel the intake manifold a lil where they sandwich. might have a slight bottleneck. hope you find a tb. i actually have a y8 tb. but i need it for a rebuild. sorry.

good luck

 

haha its ok thanks tho... b series tbs are compatable with d series motors?!?!