Hybridguitarist

So I've found all the info on how to hook up IAB into ecu but still not quite understanding it. So I have a 94 integra 5 speed manual and I'm putting a jdm gsr motor into it. It's obd1. So a20 is the evap and a17 is empty. So my question is the IAB has two wires and needs to be hooked up two different ways? One in a17 for the 12v source and the other I'm not sure about. Could someone elaborate a little on this for me. This is the only thing I have yet to figure out. Anything helps. Thanks again.

HondaPartsHero

Two ways really:

1. Depin the wire from A20 and pin it to A17. Then plug the Evap purge connecfor into the IAB. You'll obviously delete the Evap but no codes will be thrown.

2. Run a two wire connector from the IABS, one wire goes to A17, the other wire tap a switched 12V source.

Hybridguitarist

Okay so first question, without the evap in it won't throw a code and in turn will not effect emissions? I live in Washington state so we have to do emissions. Second question, so the connector for the evap will plug right into the IAB and all I have to do is re-pin the evap to a17 and all done? If so than thank you so very much for elaborating on this.

Hybridguitarist

As for the second method, would the 12 v source be a ground? Like hooking it up to the thermostat housing or something along those lines?

JRCivic1

A17 is actually the GROUND for the IAB circuit. The other wire in the two pin plug connector needs to be connected to a 12v+ source... pick a wire in the engine harness that is yellow with a black trace.

Hybridguitarist

Got it. So any yellow wire with black strip on the wiring harness. the way that involves the evap is definatly the more simpler way, but know that I understand how the 12v constant thing will work I think I'm going to go that route. Thanks for chiming in and elaborating for me, really appreciated. Can't wait to start up this gsr build.

94 Civic Si

I am sorry to ask a question that is probably incredibly un-informed, but I cannot figure out these responses...

I was recently confirming IAB connections in my swap, as I understood the IAB solenoid to ground to the thermostat housing (G101). Your references to pins A20 and A17 are confusing to me. Are you talking about a JDM ECU? In which case, I thought they did not have Evap?

From the service manual for '96 Integra, IAB is pinned @ A26.

What am I not understanding?

Thanks for tolerating my question!

HondaPartsHero

1996 is obd2, your car is obd1, are you using a JDM P72 OBD2 or OBD1 P72?

Heres a diagram I made a few years back

94 Civic Si

Oh wow...
Of course my '94 EH3 is OBD1.
I just took a look through the manual for the body, and yes, the ECU/ECM connectors are OBD1, so I am guessing I have the OBD1 P72...
Thank you. This is really teaching me a lot about this vehicle.

94 Civic Si

Thanks for making this diagram! It seems that the manuals for the '94 Civic and Integra do not detail the ECM connectors as nicely as the '96 manual I used above.

This will help me when I am checking my connections this weekend.

PS: did you get my PM about VTEC connectors?

94 Civic Si

Sorry I am making a mountain out of a molehill, and I don't want to sounds ungrateful, but I think the pin-outs shown above for the IAB might be incorrectly labeled.

It looks like you got A17 and A20 mixed up...

Here are some scans from the '94 Integra manual, my first clue something was wrong was when I saw A17 in the upper row on the A connector. I wish the OBD1 manuals had a legend that labeled each pin, but that does not seem to be happening in this manual. I would love to label the connectors, maybe someday when I have a lot of time...

Hope these can help:

94 Civic Si

When I look at the purge solenoid, am I reading this correct that A20 is a switched Ground (-) for the Evap Purge Solenoid?

Rufer

Hi guys I have a question about the AIB I have a 1997 Integra GSR pretty much Stock I recently replace the head gasket, water pump, Valve cover seals etc, now that I put it back together I noticed that my
secondary Vtec/Butterly/Runners is not working at all, I can hear and feel the primary at around 4400 RPM but the 5800RPM one is not working, no CEL are flashing so I have no idea whats wrong or how to fix it I verify that the vacuum hoses are plugged in correctly, anyone has any input on how to find the problem?

94 Civic Si

It sounds like you did some good maintenance! If you replaced the head gasket, I am wondering if you got all the vacuum lines to the IAB hooked back up correctly?

Rufer

I had an experience friend help me with the job and I he also have no idea whats wrong, I had check several time the vacuum hoses are connected properly and they are. IDK if the IAB is bad would the check engine light come on the dashboard? or how could I check if its working? all the post I seen are aftermarket Manifolds or they have the CEL on which aren't too helpful in my situation since mine is all original and no CEL are on lol!

94 Civic Si

If you are all nice and original, I would probably start asking this crew: Acura Integra - Honda-Tech

Rufer

ok I will do that thanks!

HondaPartsHero

@94 Civic Si - you're correct I need to back and fix that diagram. Both IAB and evap are switched ground activated.

The IABs won't throw a code. I'll try to post some troublseshooting pages later

94 Civic Si

Thank you for confirming, I was afraid I was missing some other key detail!

94 Civic Si

So it looks like it gets more interesting! My B18C1 is from 1996 (OBD2) and I saw the swap shop had connected the (-) terminal of the connector to the G101 at the t-stat housing. "Uh-oh" I thought! But when I check the FSM for '96, the ground terminal goes to body ground!
So what the heck is the (+) terminal of my IAB hooked up to at my OBD1 P72 ECM? Not like any other terminals are going to switch off (+) @ ~5000 RPM

Below scan is from 1996 (OBD2) Integra FSM for troubleshooting IAB connector:

94 Civic Si

That seems like a big change for OBD1 to OBD2 - same connector, but switching polarity of terminals and switched ground vs. switched (+).

Hybridguitarist

Okay so I should be doing something differently with the IAB than what was said early on? So where should I be hooking up the IAB in my p72 obd1 ecu, and where should I be hooking up the yellow/black wire from the IAB? Unless nothing has changed for my setup than what was stated above than disregard. But if this effects my swap than please elaborate on this.

94 Civic Si

I think I need help. It looks like my IAB is hooked up to ground (-) at the thermostat housing (G101) and the other terminal is hooked up to A17.

Am I correct that my IAB has likely never operated hooked up in this manner, as it never saw a (+) 12 signal?

Am I also correct that in the presence of no voltage, the intake operates with the valves open, and thus uses the short runners - to the detriment of low end torque?

If yes, I have been missing out on IAB for the last 14 years...

Scans are from the '96 OBD2 FSM:

94 Civic Si

Am I reading the OBD1 FSM correctly that both use (+) from the PGM-FI main relay via the YEL/BLK wire?

94 Civic Si

If I understand things correctly, which I may not, the (+) YEL/BLK comes from the PGM-FI main relay, and the switched ground @ A17 will be on until the engine hits 5750 RPM. If I were you, I would wait until someone more knowledgeable than I confirms.