Hey guys. I need to wire up the IAB, last thing, but I need either a wiring diagram or someone who has done this to help. The two wires have colors red/yellow and green/blk. I'm thinking the red/yellow goes to the ECU (pin B16) and the green/black is ground. Thanks.

 

You're slightly backwards as to the positive/ground.

First off, are you SURE you have an OBD2b P72? I'm asking because the IABs are different on them, and most people don't run them because of the immobilizer. I'm assuming you do, because I think that's the only one that has IABs on pin B16.

Now, if you DO have an OBD2b P72, the IABs are different from the older ECUs. On the older ECUs, the ECU provides the voltage, and the other side of the connector goes to ground. On the 2Bs however, the GROUND goes to the ECU pin, and the other side goes to a 12V source.

As far as colors, I can't remember exactly which color or which side of the connector was supposed to be positive. On mine though, I have the positive side running to the battery (although you can splice it into any other 12V source), and the negative side running to pin B16 on the ECU.

The idea is that the ECU switches ON the ground below 5500rpm, and closes the circuit which holds the solenoid open. Then, at 5500, the ECU cuts the ground, the circuit breaks, and the solenoid closes, thus cutting the vacuum to the diaphragm, which OPENS the IAB secondaries.

I know, it sounds strange, but that's how it is. When I did my swap, it took me FOREVER to figure this part out, because everyone kept giving me information about the OBD1 and 2a P72s. Ultimately, I had to dig though the wiring diagrams in the manual and figure it out myself.

Once you get it wired up, you can test that they're working by revving it past 5600-ish. At that RPM, even under no load, you can watch the diaphragm open and close.

 

yes, I have the same exact set up as you. I just need to know wire color, is there a chance you can check for me to see which wires you have going to which?

 

Mine doesn't follow standard colors... I used a random honda round 2-pin connector, and spliced it to some plain old parts-store wire.

Unfortunately FFsquad doesn't say either. I'm looking through my service manual now.

 

ahhh ic. Hm, lets hope your helms manual says.

 

Hrm.

According to manual, it should be red/blue on ECU side, and black/yellow on voltage side, at the connector... I guess. Doesn't seem right to me for some reason. I'm all turned around because I have a 1998 manual with a 2001 supplement, and the supplement seems to say a few things that contradict my memory and ffsquad... as well as not really saying much about the *completely* different ECU plugs between 98 and 01. Really, I'm not surprised that you have odd wiring colors there.

My guess is that ffsquad doesn't say, because most people just run their own wire for that on swaps into civics. I wrapped mine in black wire loom with some black electrical tape, and it looks OE.

Anyway, good luck.

 

Yea I just found the wiring diagram for it as well and its saying the same thing, red/blue to ECU and yellow/black to 12V source...sigh...I'll figre it out haha.

 

I put the red/yellow wire to ground (since it showed it was leading to the ECU and you said ECU was ground) and the black/yellow to the battery directly and all I hear is a click, I don't see it moving...so shoudl I be hearing a click, or hear something actually moving? I wonder if the solenoid is dead if I'm hearing a clicking sound.

 

When you start the car, you should actually see the the diaphragm open, on the driver's side of the intake manifold. When you rev it above 5600, you should see it close. Sometimes, when I shut my car off, I can actually hear a hiss as well, as the vacuum escapes from the tank.

Unfortunately, I'm really not sure which side is supposed to be ECU, and which side is supposed to be battery on the 2 prong plug. I can't really check mine, because I have it all wrapped up in the wiring harness, and both wires are red. I just checked, and I do know that I have black/yellow on the left pin, and red/green on the right, but I'm not sure which side goes where, and can't check because it all disappears into the harness.

Try this:
We know that one side should go to 12V and the other goes to ground. Try running one side straight to battery, and ground the other. When you plug it into the solenoid, the diaphragm should click open. You can visually watch it move.

If it doesn't, then try swapping sides on the 2 prong connector. It should work then. Even if it's an OBD2a solenoid, it should still work, just the pins are swapped.

Once you know which side is which, then you know which side to run to B16 and which side to run to battery.

I think, anyway. I can tell you that I really had to screw with it for a week or two before I figured it out. Once you do though, you can VISUALLY see the diaphragm open when the engine is started.

 

Thats exactly what I did a few hours ago. I put one wire directly to the positive side of the battery and one to the negative side of the battery...it clicks when I put: (red/yellow to negative terminal) and (green/black to positive terminal). I thought I was suppose to see the diaphragm move, but all I heard was a click, so I reversed (red/yellow) to positive and (green/black) to negative and I still hear clicking, but no diaphragm moving. Not sure what's going on.

 

Ok vindicator, I figured it out. I realized what you said about when you shut the car off and heard the valve closing or letting air out....so I figured I should start the car after I was going no where and hearing only the clicking sound to see if maybe the valve was stuck or something. I go and start the car then turn it of. I ONCE AGAIN haha, put (red/yellow) to negative terminal and (green/blk) to positive and I can here it opening and closing!! TIGHT!! It's not broken!! haha. Last question is, which 12 volt wire did you tap into? IPG1 or IPG2? I want to make this as stock looking as possible because BAR sucks

At least now we know the red/yellow goes to ECU and green/black go to a 12V power source.

How come ur the only one chiming in and helping haha, but I do apprecaite the help

 

nvm, I noticed you just said you tapped directly into battery haha. I think im going to tap into a 12V ground wire on the main harness, I believe its the black/yellow wire on the main harness...correct me if I'm wrong.

 

12V ground? Ground should be B16 on the ECU, right? Are you talking about 12V supply?

yes, I ran it straight from the battery, but you can do it from any 12v source that's continuous while the engine is running. So, you could run it into the underhood fusebox and connect it to something in there. Or, you can splice it into the 12V on the EVAP purge. Or from an injector. Really, you can splice it into just about any other wire that carries 12V.

Glad you figured it out. I've been saying for years that IABs make a significant midrange difference on a gsr.

 

why the heck did I say 12v ground -______________-

but yes I meant 12v power source haha.

Yeah, I think I will just be splicing into the evap purge. Thanks for all the help man, gladly appreciate it! I will let you know how BAR goes.

 

The IAB is working. Just for future reference for anyone else doing the IAB wiring for obd2b...the wire going to the ECU is the signal wire and the second wire goes to a 12v power source, which I tapped into the evap purge solenoid on the intake manifold. When I connected the negative battery terminal back on, I can hear the vacuum on the IAB...thanks again vindicator for all the help man, much appreciated

 

Ok Iv tried everything in this thread and Im still having a problem which I think might be because the IAB solenoid I have is not compatible with my 0bd2b ecu, but correct me if Im wrong...I swapped a 98 GSR in to a 2000 LS body and am running an 0bd2b ecu....

If I connect one wire from my solenoid to 12v power and the other to the ecu, the iab's stay open and there is no movement (I tried switching the wires). Basically the solenoid stays closed and the vacuum gets to the solenoid and does not go any further, which I tested by pulling off the vacuum lines. Now if I wire the solenoid so that one wire has 12v and I ground the other on the block the solenoid opens and the diaphram opens (closing the butterflies). So I know the solenoid works but only lets vacuum pass through when it has power so if the ecu does not provide ground until 5600 rpms or so, then the diaphram will not have vacuum until 5600 rpms at which time the iabs will close instead of open!

Basically its like my solenoid is doing the exact opposite of what its supposed to be doing and Im thinking I might have to buy a solenoid from an obd2b GSR but wanted to run it by you guys before I waste my money. I looked up the part numbers and the solenoid for a 98 gsr is the same as a 2000...so maybe my wire harness or specifically the solenoid is actually older than 98?....If anyone has any suggestions Im all ears

 

#1 should go to B16 on the ECU. #2 should be grounded.

 

thanks for the reply but I already have my pinouts done correctly so thats not the problem...