I got a 99 Honda civic dx not too long ago and realized it was a mini me swap and I was wondering why when I plug in my P2P ecu it throws a idle air control valve circuit malfunction engine code but when I plug in the original ecu it says my car is fine and the only code I have is the oxygen sensor that I am aware of but other then that can anybody explain why one ecu tells me I have a idle air control valve code and not the other? And do I need a knock sensor for my car to run vtec I will post photos below thank you.

 

Sure. The DX ECU is set up to run a 3-wire IACV... and if you are using a manual P2E ECU, it runs a 2-wire IACV. Since the car is wired for a 3-wire, you get no code for the IACV. When you plug in the P2E, it cannot deal with the 3-wire IACV, so you get the code. You will need to re-wire that and use a 2-wire IACV (this means that you must use a manual intake manifold) and you will have to install a Knock sensor so that VTEC will work.

 

JRCivic1, sorry just now really getting into the mechanics of the vehicle my car is manual and I have both manual ecu but in order for me to run vtec I need to use a manual intake manifold could it be from a d16y8 bc I want the extra power or torque and then I would have to switch the IACV to a 2 wire? Just to confirm?

 

Yes, you can use a Y8 manual intake manifold... just make sure that you use one from the proper model year cylinder head... the '96-98 and '99-00 heads and intake manifolds are different. They must match or you will have a huge vacuum leak.

 

I appreciate it for the heads up but i have a d16z6 head I know I should’ve gotten the p28 ecu bc I figured it would still do the job but should I get a 1992-1995 Honda civic si manual intake manifold that belongs to my head or still get the ex manual intake manifold now that you mentioned that?

 

Since you have a Z6 head, you can use either a Z6 or '96-98 Y8 intake manifold. The rated HP difference between the two engines (Z6 and Y8) is only 2 HP, so you should be fine either way.

 

Thank you so much man helped out a lot and I plan on doing the z6 intake manifold js bc it’s cheaper then y8 but since I plan on going with the z6 intake manifold can I re use the y7 throttle body with the same iacv and js rewire it to two wires or do I use a z6 throttle body with a z6 or b20 iacv? And still re wire it to two wires?

 

You really need to use a Z6 style throttle body... and you will HAVE to use a 2-wire IACV like what is found on the Z6 intake manifold. From the 3-wire IACV plug on your Y7 engine harness, you will NOT use the orange/black wire, and at the ECU end, you will need to move the blue/black wire to the appropriate pin location and plug in the manual ECU that you have acquired.

 

Thank you man I found the orange and black wire on the iacv but I had ordered a d16z6 intake manifold came with fuel rail injectors and pressure regulator along with the iacv and throttle body do I also use the d16z6 throttle cable right? Sorry for the questions I just don’t know much about the swaps and into debt about what to swap out. And one more thing sorry I use the d16z6 knock sensor or y8 knock sensor?

 

Use the Z6 throttle cable and the Y8 knock sensor.

 

Really appreciate it a lot thank you but I’m not sure if I need a knock sensor because I just realized my d16y8 ecu doesn’t throw the code when I switch to it so do you think it would throw a code if it wasn’t plugged in? Or if I didn’t have a knock sensor? Because the previous owner before the one I bought it from did the mini me swap js never completed it and I’m wondering what if he maybe did the wiring already because the vtec ecu isn’t giving me a code for it

 

You were not very clear here... are you stating that when you switch to the Y8 (P2P) ECU, you do not get a Knock code or you do not get VTEC codes (VTS or VTP)... or BOTH ?

 

My bad man my head is all over the place but when I switch to the p2p I don’t get a knock sensor code. I get the vtec code which I know isn’t plugged in. But essentially what I’m asking is, is that since it’s a vtec ecu wouldn’t it throw a knock sensor check engine light if the knock sensor isn’t plugged in because my and I’m wondering if the reason why it’s not throwing the code is because does it mean I have one? I can’t really tell with my manifold in and the way and stuff.

 

If you are not getting a Knock code, there must be one plugged in. On the Y8 engine, it is normally found on the back of the block just under the intake manifold, close to the water pipe. It is easier to see from below.