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A friend of mine did a B18 swap in his civic. The engine and P72 are both JDM. He had the purge wires from the civic harness (B18 harness was hacked... had to use civic harness) connected to the IAB solonoid. Obviosly, the weren't working. After doing much searching, I learned that the JDM P72 sends a Positive 12V from pin A17 to activate (close) the IAB below 5750 rpm. So, we cut the yellow with black stripe wire (switched 12v) from the plug and capped off the hot wire. Then, the plug end that was cut, I soldered in a wire and mounted it to ground. I moved pin A20 (purge on civic) to pin A17, and voila!!! The IAB works with the JDM P72!!

***Here is the problem***

We chipped his stock P28, added datalogging (which works with ECU control... very cool), and extra features using a USDM P72 codebase with knock disabled. Knowing the output needed to be 12v for the IAB, I did the ODB2 version of Add IAB to P28. The IABs did not function with the P28, but did with the JDM P72 after our rewire.

On the P28: I have pin 1 of IC15 desoldered from it's hole, and jumpered to hole C of Q34. I have c61 in place with the proper polarity.

Somewhere I read that you need to switch A17 to A19 after this mod... tried that and it didn't work either.

here is some shots of my work... did I do it right?






The brown thing you are seeing in the corner of the pics, is the max233 serial pcb I made.

Any advice would be appreciated! I will do some more troubleshooting tomorrow, and hopefully this will help someone else in the future!

**edited to add comment that we moved A20 to A17**

Just did some testing..

Vout on IC15 does go to pin A19... so on the wiring harness... connect the IAB wire to A19 --- this needs to be added to the WIKI in the OBD2 section of this http://www.pgmfi.org/twiki/bin/view/Library/AddIABToP28


With no load at A19 it is batt voltage as per the datasheet
with load (12v tester) A19 is 0v.

I cut the wire that is going to q34, and shorted Vin on IC15 to 5v with a 10k resister.

when Vin is high (5v) Vout is 12v and the light comes on in the tester connected to A19.

***So, IC15 is correct and working*** I am not getting 5v from the contol hole of q34.

Here is where I am basing this mod from http://forum.pgmfi.org/viewtopic.php?t=3365

Do I need to use a certain P72 codebase to control q34? We are using the P72 USDM rom that comes with crome in a USDM P28.



*** I need to know how to make control hole of q34 work... this will solve my problem ***

I have a sneeking suspicion Q17 is required!

I traced back the control pin of q34 to it, but in the WIKI, it says "above procedure not needed"

I will take Q17 out of my ECU and try in this one tomorrow, and let y'all know the results.

PLEASE someone that can help verify the OBD2 IAB procedure... chime in whenever you can... Deluded... you seem to be the pro at this... your input?

OK, I haved solved my problem! (my electronic engineering degree pays off!!!)



For positive output ( 12v+ ) to control IABs for JDM or OBD2, you must have Q17 installed which is an A143 info here: http://www.pgmfi.org/twiki/bin/view/Library/A143


the rest of the instructions in the WIKI are correct after the statement "above procedure not needed"
And if you are using IC15, the IAB output will be A19 on the OBD1 harness.

IC16 Vout goes to A17, which is the correct IAB pinout, but I did not trace the DIAG line to see it using it will interfere with anything.

Can ADMIN please add this info to the WIKI write up? I would if I knew how.

on it

I figured out how to edit WIKI entries, so I added the pertinent info to http://www.pgmfi.org/twiki/bin/view/Library/AddIABToP28

I just don't know how to add pictures. The second pic in my first post of this thread should be added to show how to connect IC15 to Q34.

Glad I could contribute a tiny bit.

you can attach files to wiki pages using the attach thing. If you attach an image, you have the option to link it on the wiki page you attach it to. Standard HTML image stuff.

Props for adding the info! Thankyou!

Ok, I am a little confused. I am assuming that ALL the ecu's you are modifying here are OBD1. Questions:

1. Why does an OBD2a>OBD1 conversion harness need to have IAB (A17) moved to A19? Are you saying that A17 is correct for IAB enabled ecus ONLY such as P72 and P13?

2. Do you have to have IC15 installed in a P28 for this to work? In the first picture it doesn't look like IC15 is installed. In the other pictures, IC15 is being used. I.E. can you have IAB working without both IC15 and IC16 installed?

3. Can you check out IC16 to see if it can be used so that the normal A17 pin can be used?

Thanks!

Answer to 1. A17 on a OBD1 P13/14 and P72 controls the IAB. If you have an OBD2 engine, or a JDM OBD1 engine, the ECU needs to send a positive (+) signal to activate the IAB solonoid. Deluded's original instructions used IC15. This goes to A19. So, you must move pin A17 to A19 if this is the conversion you are using.

Answer to 2.The first picture is for Negative (ground) output to make the IAB work. This is for USDM OBD1 engines. IC15 is not needed for this procedure. Also for this, you leave your harness alone as this will send a ground to A17.

Decide if you need 12v or Gnd to control your IABs. If you need Gnd, just do the top half of the instructions. If you need 12v, ignore the first picture and those instructions, and skip down to where it says "ODB2 & JDM B18C conversions: ( ECU sends +12v, IAB wired to GND )"

Answer to 3.Yes I could, but I can't guarantee how soon. From my initial inspection, yea I think it will work to use IC16 instead, but I am not sure. I am thinking if it where possible, Deluded would have done it that way to begin with...

Ok, I get it now. So for example if you were using a JDM H22 head you would need to send +12v (A19) to the IAB; if it was a USDM H22 you would just ground it (A17). I (and I am sure others) would appreciate you getting it to work on A17.

Thanks!

AIB conversion...
ADD:
Q17(A143)...already present on auto 11F0/1720.
*Q34(D1980)....already present on auto 11F0/1720. may use PCS trans: Q31(D1980)
*jumper R135(trans side) to D13(arrow side)

Remove:
R135...11F0/1720 autos mostly
R150...1980/LS only

* obd2 conversions: (*) are not needed...cut control leg of IC15
short and solder signal carrying wire to it, thread wire through
desoldered hole and solder 5151s in place, solder other end of
wire to control-hole of q34 on bottom of pcb. add tantalum
cap at C61.

i have been using these notes for at least a couple years. i guarantee they work and no pin swapping is nessasary.

ps: i add D13, too. the solenoid has a coil so the diode really should be there.

Vernon, I agree that no pin swapping is needed for OBD1 version of this mod, but IC15 output goes to A19 for the 12v+ version... If IC16 was used, then no swapping would be needed. Are you using IC16? Trace it back you will see what I mean.

I have done both versions of this on a P28, and I had to move the harness to A19 for the JDM (or OBD2) B18C version. Maybe I did something wrong, but I don't think so. I found that in another post somewhere too that you need to move wires.

step 3 (add jumper...) takes care of that... only required for obdI iab btw.

also, tuned a '01 'lude today (mostly ) and can confirm that they require a ground side signal from the ecu for iab control.