Alexanderdj91

Hey guys, this is my first post so first off it's nice to meet ya'll.

I have a story for those who would like to hear.

About a month ago I bought a 2000 civic ex manual coupe. I thought I got the car for a steal but I didn't practice my due diligence and I ended up getting royally screwed.

So the car doesn't have the original engine in it (2000 d16y8 VTEC). Instead the car has a 1999 d16y7 non vtec engine in it, but everything else including the intake manifold and wiring harness and ecu was still from the stock y8. The car started throwing codes and running really rough and bouncing the idle from 1500 RPM to 2000 RPM.

So I checked the codes and first thing I found was a code for a bad O2 sensor (Sensor 1). So I bought a new O2 sensor and replaced that and that code went away. I was also getting some IACV codes (can't remember which codes they were now but I have more to say on that later) so I took the IACV off and cleaned it but it was brand new so the person who had the car before me must have just replaced it.

I also did some research online relating to having a y8 intake manifold with a y7 head and saw that the manual y8 intake manifold has air injection ports that can create a vacuum leak when used with a y7 head. So I took the IM off and sealed the air injection ports and put that back on.

I also saw that everyone said you needed to match the ECU to the engine so I went and found a P2E y7 ECU and plugged that in.

Car was still running badly with either ECU in so I did some more research.

I found out that the y7 and the y7 P2E ECU used a 3 wire IACV attached to the throttle body whereas the y8 manual used a 2 wire IACV attached to the back of the IM which is what I had. So i found a y8 automatic throttle body (which uses the 3 wire iacv just like the y7) and put that on. I got a 3 wire iacv plug from the junkyard and wired that to my harness and added a wire to run to my ECU to match the 3 wire IACV setup.

I did the reverse of a 3-wire to 2-wire IACV fix and on the ECU B connector plug I removed the #23 pin and moved it to the #6 pin slot and I added the orange wire that I added to the IACV to the #15 pin slot.

I thought for sure that the above IACV fix would work as it seemed my problems were the exact problems an IACV issue would cause and because other people have done that and had it work out fine.

However my car is still running rough and bouncing the idle, except now it idles higher and bounces from 2000 RPM to 2500 RPM.

The IACV CEL codes did disappear though. But now a new code has popped up. P0135 02 sensor heater circuit malfunction Sensor 1. However remember the sensor 1 O2 sensor is the one I just replaced.

So now here I am today. I'm pretty much out of ideas on what to do next. As much of a pain this car has been so far I've really enjoyed working on it I'd love to be able to get it working and not have to quit and cut my losses with it.

Any suggestions or ideas on something I might have missed?

Alexanderdj91

This is the info I used to do the reverse IACV fix. (The image is showing a 3 wire to 2 wire IACV fix and I reversed it into a 2 wire to 3 wire fix.)

tutran99

I actually have the same problem lol, you ever fix it?

Former User

^You're better off creating your own thread because the OP has not returned since making the second post of this thread.