JDM96SpecCTR

someone told me that to use an obd1 computer on and obd2 car u need to change this to a 2 wire...how would u do tht and will that fix the idle problem??

EE_Chris

Some OBD2 equipped cars used a 3-wire IACV - namely all automatics and the D16Y7 5-speed.

OBD1 does use a 2-wire IACV; To convert your existing 3-wire to a 2-wire you would need the 2-wire connector to graft onto the 3-wire harness (typically the orange wire is left hanging). You would then need to make sure that the IACV control wire is going to the correct spot on the OBD1 ECU.

And what idle problem are you talking about?

JDM96SpecCTR

well my car is a 96 with the y7 motor but i put on a y8 manifold and everything been seeming fine until i put in an obd1 ecu....the idle bounces quickly around 1500 and i get a code 14 for iacv and the valve is sucking at full strenth it seems. i put my finger over the hole and the idle is ok but i tried to rev it like that and it seemed something is wrong still

now like i said, with the icv on there from the d16y8 i got no problems with my stock computer, only with the obd1

EE_Chris

Well, if you're using a Y8 'auto' IACV, which happens to be a 3-wire configuration, then with your stock ECU you should have a good idle - they are the same IACV.

But OBD1 doesn't have a clue as to what a 3-wire IACV is....

fjt

Heres how you fix it..It is explained at the bottom.

shadow103rd

not to jack your thread...do 96-00 with y8 manual's have a 3 wire or 2 wire.

Jon

EDIT: from the pinout diagram, under the misc notes, says that 96 EK Civics dont need to do this modification.

Pfieff

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by shadow103rd &raquo;</TD></TR><TR><TD CLASS="quote">not to jack your thread...do 96-00 with y8 manual's have a 3 wire or 2 wire.

Jon

EDIT: from the pinout diagram, under the misc notes, says that 96 EK Civics dont need to do this modification.

</TD></TR></TABLE>

96-00 y8 manuals have a 2 wire IACV

stinker504

Can someone post up how to do it with an OBD2B system? I've been wanting to install hondata on my 6gen accord turbo automatic for a year now.

JDM96SpecCTR

i did the wiring like i said but i still get the super idle so it looks like im gonna block it off because theres no way i can use a 2 wire iacv without changing my intake manifold again which i am not doing. my iacv connects to teh bottom of the tb wheras most are on the back of the manifold. the 2 wire and 3 wire are divvernt shapes and do not look interchangeable

EE_Chris

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by JDM96SpecCTR &raquo;</TD></TR><TR><TD CLASS="quote">i did the wiring like i said but i still get the super idle so it looks like im gonna block it off because theres no way i can use a 2 wire iacv without changing my intake manifold again which i am not doing. my iacv connects to teh bottom of the tb wheras most are on the back of the manifold. the 2 wire and 3 wire are divvernt shapes and do not look interchangeable</TD></TR></TABLE>

*scratches head*

You tried to do the IACV fix but didn't use a 2-wire IACV??

2-wire IACVs, when you unplug them, they close down and seal off.

3-wire IACVs, which are a rotary type, when you unplug them, they stay OPEN and sometimes open even more.

You do not set the idle in the same manner between an ECU controlling a 2 vs 3 wire IACV. You don't unplug the 3-wire to set the idle.

JDM96SpecCTR

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by EE_Chris &raquo;</TD></TR><TR><TD CLASS="quote">

*scratches head*

You tried to do the IACV fix but didn't use a 2-wire IACV??

2-wire IACVs, when you unplug them, they close down and seal off.

3-wire IACVs, which are a rotary type, when you unplug them, they stay OPEN and sometimes open even more.

You do not set the idle in the same manner between an ECU controlling a 2 vs 3 wire IACV. You don't unplug the 3-wire to set the idle.</TD></TR></TABLE>

before i did the wire harness fix the iacv was not being recognized by the obd1 computer, so it was basically like it was unplugged...so i switched the wire over, and the other wire that u are supposed to cut i didnt cut, because there wasnt a wire there on the obd2-1 harness. now the iacv is active but it is fully open it seems, and theres no way for me to control itwith an obd1 ecu

now the problem is i cant even use a 2wire iacv becasue my intake manifold is sealed on the back, where most other iacv's would be. it is on the bottom of the throttle body, with nothing on the back

my options are either block it off, get a 2 wire iacv, plug it up and bolt it to the back of the IM (there is one threaded hole for where teh 2 wire would go) just so i dont get a cel, and get a fitv for teh bottom of the tb, or a tb that doesnt use either on the bottom of it.

by the way, do b series tbs bold up to y8 manifolds??

EE_Chris

D16Y5, Y7, and Y8's did not use a FITV, so don't bother with the notion that you could put one your throttle body.

Your manifold, though made for an auto application, can be drilled and tapped to accept the 2-wire IACV - just like the 5-speed version of the same manifold already has done to it. At this point though, you will need a different throttle body to get rid of the 3-wire IACV - you'll need the 5-speed Y8 t-body.

blundar

One of my buddies has a similar but different problem.

He has a 96 HX coupe that originally had a 2 wire IACV (fairly sure). The stock motor blew, and has been replaced with a 97 D16Y7 with a 2 wire IACV. The ECU that he has is throwing a IACV code and idling the car erratically. As far as we can tell, it is expecting a 3 wire IACV. The 3wire - 2wire wiring has been posted here, but anyone have any ideas about going the other direction?

blundar

anyone?

EE_Chris

If his 96 Hx was a 5-speed, then YES, he has a 2-wire IACV.

This particular D16Y7 that was swapped in - Does it have a Y8 manifold? I ask, because absolutely no Y7 used a 2-wire IACV.

What ECU is he actually using?

If the ECU is expecting a 3-wire IACV, then you'll need to source a 3-wire IACV engine harness plug (to graft onto the existing harness), add the third wire back to the ECU to the correct spot and move a wire.

Since it seems he is using a OBD2a ECU:

a) The 3-wire plug will have a Yel/Blk, Blk/Blu, and Orn wire - match up what you can (Orn is left hanging).
b) Run a wire from the Orn to ECU pin A13.
c) Move the wire currently residing in A12 (Blk/Blu) to A14.

That should be it to convert from 2-wire to 3-wire.

liquidxEG

Anyone know if a 01 GSR (obd2b) has a 3 wire?

(and if you can take a peek at my other thread on how to get a JDM ecu to work with it w/o throwing a cel =P)

steve0unce

does anyone know if you have a 3 wire iacv with an obd1 give a bad idle? like around 10hg?

EE_Chris

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by steve0unce &raquo;</TD></TR><TR><TD CLASS="quote">does anyone know if you have a 3 wire iacv with an obd1 give a bad idle? like around 10hg?</TD></TR></TABLE>

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by EE_Chris &raquo;</TD></TR><TR><TD CLASS="quote">But OBD1 doesn't have a clue as to what a 3-wire IACV is....</TD></TR></TABLE>

If anything, a 3-wire IACV will create a big *** vaccum leak causing your idle to surge.

EE_Chris

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by liquidxEG &raquo;</TD></TR><TR><TD CLASS="quote">Anyone know if a 01 GSR (obd2b) has a 3 wire?

(and if you can take a peek at my other thread on how to get a JDM ecu to work with it w/o throwing a cel =P)</TD></TR></TABLE>

No - its a two wire. No Integra has a 3-wire IACV.

You will NEVER find a way for an ECU that originally controlled a 3-wire IACV to control a 2-wire IACV and vice-versa.

biggmike2

well i just did axles on a 96 hx manual and it has a 3 wire IACV if you dont believe me i can take a picture.

EE_Chris

Please do. And I can take a scan of my Helms just to show where my info came from as well, if need be.

perlmeister8

http://forum.pgmfi.org/viewtopic.php?t=2044

I used this and the cell went away

JDM96SpecCTR

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by EE_Chris &raquo;</TD></TR><TR><TD CLASS="quote">

You will NEVER find a way for an ECU that originally controlled a 3-wire IACV to control a 2-wire IACV and vice-versa.</TD></TR></TABLE>


you are wrong!!! and im so happy about it...i followed the directions in the link above me adn guess what?? my 3 wire iacv is working on my obd1 ecu. damn and i just bought a whole manual y8 manifold and throttle body setup, and now i got it working and dont need it...

so anyone loking for a y8 mani and/or tb PM me

EE_Chris

Well sir, congratulations then. This is the first time I ever heard of this happening.

A 3-wire IACV has two control lines that play tug-of-war with the rotary piece inside of it. A 2-wire IACV has 1 control line. But the assembly is different - a 2-wire uses a spring/plunger assembly.

If you say it works, then...fair enough.

It seems what has been accomplished by hooking it up this way is that IACV N coil has been permanently grouned by A23 and so IACV P is being controlled, through the jumper from A12 to A14, by A9.

I wonder if the IACV N coil will burn up though from being constantly grouned?

JDM96SpecCTR

yea i was kinda thinking there must be some side effect...but i have the parts coming to me so i will see if anything happens...if it burns out i have another 3wire, and i will have the 5 speed mani and tb and 2 wire...but no plug