ENG: H23 Intake Manifold Swap (56K die!!!)

[Tippey764]

I just finished the swap. Everything went great exept i had to swap the little wheel thing the throttle cable hooks up to.

With the h23a1 on there the throttle cable was too tight and held the throttle open just a little even with it all the way adjusted to full slack

With the f22a6 one on there, there was pleanty of slack so i could adjust it just right.

[Airhonda92]

Reinstalling everything.

21. You’ll need to swap out the EGR valve to the new H23 manifold. Do this first before the injectors so you’ll have room for your wrench to tighten down the EGR valve. You’ll also need a new gasket. Remove the old one with a razor blade. Mine came cleanly off with a razor, just don’t scratch up the surface. As a side note, the h23 and f22 egr’s fit each other’s manifold, but use the accords EGR as it has the correct plug for our purpose.
22. Now swap over the injectors and fuel rail. Clean the injectors with some carb cleaner. You’ll notice that the yellow tip that was in the intake manifold is crusted with carbon. Get the carb cleaner, spray it on a towel, and wipe it away. MAKE SURE NOT TO CLOG THE INJECTOR NOZZLE. REPLACE ALL INJECTOR SEALS as stated in accordztech’s injector seal replacement guide. I didn’t do this and put me behind a day. So do everything right the first time. Side note: we are using the F22 Fuel rail because the service bolt on the H23 manifold is on the wrong side and our fuel line won’t reach it. So just use the F22 because they are interchangeable.
23. I also had to change out the IAT. Don’t lose the little o-ring washer.
24. As for the TPS sensor on the throttle body, I had to use the old one on my f22 tb. You’ll notice that the sensor is “riveted’ in there. You’ll need to make a slot on top of each bolt and then get a flat head screw driver and unscrew them. Voila. I’ll get to setting the tps sensor later. You may need a new tps gasket, I just reused my old one.
25. Throttle Rotor – this step may be optional. I’m not sure if this is a manual / auto thing. But the h23 Throttle rotor (TR) only had one plug for the throttle cable. My auto f22 TR had 2 plugs/holes - 1 for the throttle cable, 1 for the auto tranny cable. You’ll see what I’m saying if you get to this point. You may not have to do it.
In order to remove the rotor, you have to remove the 10mm bolt and the washer on top of the throttle rotor. Then unclip the springs. The rotor will be stuck on there, so pry it off with a screw driver. Now be careful, the TR might fly off ‘cause of the spring. Now just switch the throttle rotors out. One problem I encountered was that when I used the f22 TR, the butterfly for the TB didn’t close all the way. There is an adjusting screw that allows the TB butterfly plate to close all the way. I believe it’s an 8mm screw.
26. Go to back to the engine bay and remove the old intake manifold gasket. Use a razor blade and putty knife. You can also get gasket remover spray from auto zone. This process was time consuming for me (about an hour to an hour and a half) because everything was caked on there good.
27. Now life is good, I put the bottom half of the h23 (just the runners) and hand tightened the bolts just so the intake manifold would stay put.
28. make sure all wires are out of the way (tps wire, iat). Make sure you transferred everything over, yada yada yada.
29. Torque down the bolts on the manifold in a criss cross pattern to 16 ft lbs. this is a time consuming process also and am not going to lie to you.
30. Now everything is pretty reverse of removal.
31. Reconnect the water housing and MAKE SURE you reinsert that radiator house that goes from the water housing to the engine block. Bolt everything down good.
32. Bolt on the Fuel Pressure Regulator (FPR)
33. Bolt on the upper half of the intake manifold – 16 ft lbs.
34. Now hook up all the coolant lines. Now your FITV valve is under your TB instead of on the front of the IM. Just reroute the coolant lines. Same thing goes with the other pair of coolant lines that pass thru the IACV. The only that was hard for me was to get the clamps to go around the iacv – it’s a pretty tight fit. So I unbolted it and clamped it from the bottom. As for the throttle body, you may have to cut some of the existing coolant lines b/c they may be too long.

IACV VALVE radiator hose


TB radiator hoses


35. bolt back the intake manifold bracket. It fits perfectly unlike the F22a6 dual runner.
36. bolt on the starter / ignition coil.
37. replug the IAT and EGR sensors.
38. Reattach the vacuum lines. Remember to cap off unused vacuum nipples.

- Well, out the black box on the passenger side of the car you have like 3 hoses that come out on top, # 21,20 and 24 or something, 20 and 24 go to the intake manifold (two plugs right next to each other on the back of the mani), the #21 is on the throttle body, Then a red hose goes from the big port on the throttle body to the charcoal canister, and the #3 hose goes from the charcoal canister to the bottom of the black box. FPR goes to the center port on the intake mani, little sensor thing on the drivers side of the mani goes to your intake tube.

- IAB valve actuator – you can use the IAB control box and wire it to pin A17 on the EX ecu (PT6) or you can do it like I’m doing and get a vacuum line from the nipple of the diaphragm and connect it to an unused nipple.

39. reinstall all brackets removed. The H23 has the same bracket points as the F22.
40. put back the injector clip rail. Don’t forget it has 2 black 10mm bolts. Don’t over tighten it too much.
41. Bolt down the 17mm service bolt.

YOU DA MAN!!!!!!!!!!!! I litterally just finished the swap and had a vac issue which was cleared up by this thread!!!!!!!!!!!!!! THANK YOU SO MUCH FOR DOING THIS THREAD

[CB7 R3ason]

why do i have the feeling that this is going to be bitch to do

[CB7xTURBO]

does the TB have to be bypassed? can i run it normally some how? i dont want to fail smog ort visual even

and btw does it matter if the iacv doesnt go from t-stat housing - iacv - fitv - manifold?

i have it the the way it is on the h23 which is

t-stat housing - iacv - manifold
and the fitv is also by itself..

would it matter? because im getting a weird idle issue and also a popping sound when it goes down in rpm kinda like when the butterflys open and close but its not the butterflys

and btw my iab's are bypassed i do not have the ecu

[vietkid_2006]

Someone needs to make a new one with pictures. I understand only so much of it.

I'm just a visual person.

[DejectedAngel]

On a H22 swap Accord EX.

Is the iab valve suppose to close when i start the car? Which they would be in a close position right? I have the valve plug onto the driver side plenum nipple because that is the only one on there. Im also guessing it will open when the vaccum gets cut off?

[DejectedAngel]

Anyone