blowme

Aight, i have a 96 civic coupe ex, have a 98 gsr block and tranny with b16 head fully built with cams etc. When i got the gsr the iacv never worked always threw code for it. tryed some searches and found something that said one wire fix. The sensor itself has 2 wires, but the info i found said to only use one wire. I already have a pinout but can't figure this out, and i have replaced the iacv itself. If anyone else has had this problem i would appreciate it if someone could try and explain a little(last code Im throwing and idle sucks *** especially with cams!!!)
OH and everything is still obd2, nothing has been converted!!

EE_Chris

Still using the Ex wire harness? What ECU are you using?

The Ex already came with a 2-wire IACV, which is what the GS-R uses too. If you had a Cx or Dx, things would be different because they initially came with a 3-wire IACV and ECUs that control a 2-wire IACV will never control a 3-wire IACV (and vice-versa).

Care to share the link to where it says only 1 wire is used? It sounds wrong and needs to be corrected.

blowme

sorry i did a search through here a while ago, but as far as the 3 wire harness, yes thats what i had used, i had to get one from the junkyard and modify it and it was off of a auto ex. But i'm trying to wire it up directly, right from the sensor to the ecu and i can't really figure it out!! and yes i'm using a stock obd2 gsr ecu. If i can find the link to any of them i will post with the ecu printout, i know the pins are a12 and a13 but the paperwork i have says put a12 in and leave a13 out dangling, that didn't sound right so i tryed swapping them and even grounding the other wire, but still nothing.

blowme

https://honda-tech.com/zerothread?id=1243514
heres that thread i was talking about!!

EE_Chris

That diagram is spot on.

If you are using an auto Y8 harness, you will need to graft on a 2-wire IACV connector. The 2 wires of that connector should match up to 2 of the 3 wires on your auto harness - the orange is left hanging/taped up.

Back at the ECU, you do need to move A14 into A12. You can leave A13 alone because as it stands right now, its connected to nothing (you taped it off in the engine bay, remember).

Curious though - was your car originally an automatic? Why source the junkyard auto harness?

blowme

when i got the car it was stripped and the kid who had it had tek 2 engine managemnet on it, so the harness was butchered. Got the auto ex harness, i didn't even try to wire it up with the three wire harness so i cut the plug from the gsr harness and pluged it onto the iac, now i just want to run the wires directly to the ecu, i figured it would be less confusion!! So in other words just match up the colors off of the plug and run my wire right into pin a12 and leave a13 taped up right??

EE_Chris

You have a harness that has exisiting wiring that you can work with - this would be the easiest thing to do/use.

Cut off the 3-wire IACV connector from the auto Y8 harness.

Take the GS-R 2-wire IACV connector and match up its wires with the two same colored wires from the now clipped harness - the orange is left hanging/taped up. You are now done with the engine side of things.

At the ECU, put the Blk/Blu wire in A12 (it was originally in A14). The orange wire can remain seated in A13 - it serves no function at this point.

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by blowme &raquo;</TD></TR><TR><TD CLASS="quote">So in other words just match up the colors off of the plug and run my wire right into pin a12 and leave a13 taped up right??</TD></TR></TABLE>

Its a little confusing to read that but it seems your set on NOT using the Y8 harness since you want to run your own wires. If that's the case, then find a switched +12v for the Yel/Blk wire (on the 2-pin IACV connector) and then run a seperate wire from the Blk/Blu wire all the way back to ECU pin A12.

But again, it'd be easiest to use the existing wiring, make the needed connector mods and move a wire at the ECU instead of trying to run everything yourself.

blowme

Kool i appreciate your help, ill give that a try tonight see if that works
i have already tried to wire it up directly but it didn't work, so your saying on the other wire thats not in a12, needs to go to an ignition 12v source??B/c if thats the case i never tried to do that, that was prob my problem then.

EE_Chris

Notta problem for the help.

On the 2-wire connector, there is a Yel/Blk wire and a Blk/Blu wire, correct?

The Blk/Blu wire is the control wire. Its actually a ground that the ECU uses to command the IACV to open up and let air into the manifold.

The Yel/Blk wire has to supply the IACV with battery voltage, otherwise the IACV would never operate. So yes, it has to be tied to a switched ignition source.

But again, if you just grafted the 2-wire connector onto the 3-wire harness and moved A14 into A12, you'd be done and wouldn't have to worry about finding a switched +12v source....its already done for you.

blowme

kool thanks for all your help definately appreciated, now that you explained it like that i know i can get it to work!!!

blowme

sure enough i wired up a v source last night, and check engine light is gone, i finally have a cold start valve working again, thats pretty nice now i don't have to rev it!! thanks man