whpazz

I have a 98 prelude that had a h22a4 that had a 2 wire iacv i installed a jdm h22a red top that came with a 3 wire iacv. The original computer is obd2a the red tops computer is obd2b I already have the adapter from boomswanger but neither computer will make it idel. I used the harness from the car on the new engine. every thing else works fine except the idel. If any one has the wiring diagrams for this please post it on here. Or if you know the specific solution or a type of car to get a 2 wire iacv that bolts to the intake by the throtle body. THe one from the old engine will not fit i already tried. At this point i don't care wich computer i use as long as it runs and idels like it should.

Fabrik8

This should help. The Prelude pinout should be the same, and even if it isn't the concept is the same so it can be adapted to your setup.

Fabrik8

More info:

http://www.ff-squad.com/technet/

http://www.hondacivicforum.com/forum...ad.php?t=81865

So it looks like the ECU must be compatible with the IACV, which makes sense. The 2-wire IACV is a linear solenoid type with a spring and plunger, and the 3-wire is a rotary valve. So there is no way to make them compatible because the 2-wire just needs a simple low side driver to ground but the 3-wire needs an H-bridge driver most likely. Just smile and nod if you have no clue what I'm talking about.

You'll want to use the OBD2b ECU that came with that engine then, and add the extra wire (and the pinout change) for the 3-wire IACV.


It's also possible that there is a drop-in 2 wire IACV you could use, but I don't know enough about the different models to say if any of the 2 wire IACVs would fit where the 3 wire should go.

dXXX96civic

just put in a block off plate eliminate it all together....

whpazz

Ok Thankyou but unfortunatly I followed all the directions to the letter and it did not make any changes. I even wired every wire from the iacv to the obd2b ecu directly and still nothing. I originally thought I would just have to connect the third wire to the ecu but the pins must be differnt from a civic. Do you have another suggestion I'm just over dealing with this I had a guy from J-spec in ashland who was supposed to come down to Va Beach yesterday but he never showed up.

Fabrik8

That's all I've got, sorry. If you're using the 3-wire IACV, and the correct ECU, and the IACV is getting power (yellow/black wire?), and the ECU isn't damaged, everything should work fine. I know all of the Prelude pinouts for OBD1 are exactly the same as the Civic/Integra pinouts, although I'm not entirely sure about the OBD2 stuff.

If you can track down a Prelude pinout of the same OBD2 generation to compare, that should tell you everything you need to know.

whpazz

I appreciate everything man Carlos from jspec is supposed to be on the way down he said he has run into this exact problem before. I hope he is right but i agree with what you are saying 110% that is why I am so confused and frustrated I just don't want to waste time and money chasing the ghost in the machine if you get my drift LOL. I will let ya'll know what he does to fix it thanks again.

Fabrik8

No problem, hope you can get to the bottom of it.

whpazz

Ok here is the final setup obd2a engine harness with obd2b boomswanger conversion harness type s obd2b ecu the whole issue was the third wire is only a ground. I was not sure that is what it was for and tried to use a jumper with aligator clips to test if that would make it run correctly. well come to find out all that needed to be done was to make the ground more secure as soon as he put the wire under the throttle cable bracket and tightened the bolt it worked just like it should. I never knew that honda are so tempermental about their grounds. Carlos did explain that the h series are always the swap that causes the most problems just for the fact that euro-r & s have weird wiring for instances the set I just bought has a pcm that is hardly ever seen (It's a PCD) What ever that means any ways my hats off to J-SPEC AUTO and Carlos & Mitch

Fabrik8

All fuel injected cars are critical of their grounds. If you want accurate sensor function, you need an accurate sensor ground reference.

Glad to hear it's fixed.