genosbro

Okay so this is my second attempt as i have not fixed the problem in over a month. My first post was a hodgepodge mess and i have more of an understanding of what my issue is. I believe i need a simple 2 wire to 3 wire conversion but i have MANY questions as to what it is i need to do.

So i have a 2000 Civic EX P2P ECU, all stock wiring, D16Y8 Head and Intake, And a D16Y7 Block. The only thing that was changed to cause the idle issues was the block.

It idles at about 1500, and sometimes fluctuates very slightly but rapid from 1500 to 1800. It messes up my driving when trying to hold the gas steady and the engine begins to buck back and forth.

I'm throwing 3 codes as follows...
P1508 IAC Valve Circuit Failure
P0505 Idle Control System Problem
P0420 Catalyst Eff Low Bank 1 (Not sure if idle related or not)

I do know I need a wire conversion. I will purse the 16-18 Guage wire necessairy to rewire this. I've read numerous guides on how to rewire IACV, but none of them are step by step on what to do. I dont know what to do first. And my situation is backwards from what everyone else has.

My car ALREADY has a 2 wire plug, an ECU that reads for 2 Wires, and has a intake designed for 2 wire. My question is How could i convert this 2 wire to a 3 wire if my intake is going to check for a 2 wire? Wouldn't this be pointless? I dont know where to start, Although I have tons of diagrams and tutorials bookmarked but im still stumped with these questions:

1. The plug that connects into the IACV... The wires that are fed into it.. are they coming from the ECU?
2. The IACV that receives the plug is programmed for a 2 Wire, so how could rewiring the IACV plug to 3 wire solve anything?
3. Even if i wire the 3 wire correctly from my ECU where would i put the third wire?
4. Would it be cheaper to just buy a Y7 intake with the IACV on the manifold and then rewire the IACV and ECU for a 3 wire?

Alot of questions, forgive me please. I also have some facts I need to state before you answer anything.

I checked my TPS for proper voltage and there was a perfect 12v and ground. The Voltage did not flucuate as I slowly pressed on the ignition, So it cant be that.

I do have a teeny tiny leak in my lower radiator hose, I'm working on replacing it soon. It leaks about a cup of coolant in 1-2 days.

My car never stalls, and the idle seems to change as the engine heats up. Cold start is usually a bit high from 900-1200.
Engine hot idles at 1,500 and makes it more difficult to switch gears and drive smoothly.
(this is a HUGE problem considering my girlfriend is 8 months pregnant and the constant bucking makes her sick.)

When i unplug the IACV the idle is very steady and sounds almost perfect but even when i apply gas it starts surging rapidly (as it does when its plugged in) but stops when i let off the gas.

There is a hose coming from my Y8 head to my Y8 Intake that is plugged up.
I was told my mechanic that it is a vacuum hose and I'll be okay if i plugged. He said he couldn't connect it because there is usually a valve that goes there, Which leads me to my next question...

How could it not fit when it had fit before the block swap, considering I only swapped the block and nothing else? He told me there was a valve that is supposed to between those hoses. Should I buy a new hose to connect them?

kyden

not sure why you're stuck on this 3 wire thing. you only use a 3 wire iacv when you're using a p2e or automatic p2p.

are you sure your tps and map plugs aren't switched?

post a pic of the hose?

genosbro

I will post a pic when i come back from work today.
I was thinking this was possible. Are the plugs the same layout?