Joan Ventura

Hello to all.

I own a Honda civic 99 automatic since 5 years ago, I decided to rebuild as a personal project. I bought this civic with engine problems and like 2 years ago I changed the engine.

This Civic is like a transformer that Honda sold in my country Dominican Republic. It has 2000 front end, but the trunk is 98, it came with a d14 engine, and many other adaptations..

Well, I changed the engine to a JDM D15b non vtec, because the original jdm d14 was not avaliable in my country. The problem is once in a while the car lose power while running, or when I'm in the red light the rpm goes almost at 0 rpm, and start shaking. Sometimes I think it will power off.

Some people said its the IDLE valve, so I bought a new IDLE valve. When i went to changed it, I was surprised the car has 2 IDLE valves: one on the throttle and another on the manifold, but this one is disconnected. I was like WT???

I'm trying to solve this problem and rebuild my car, So i went to check the manifold, so it has a P2P, when i went to the ECU it has PHX-G92..

So, what do I need to fix my car? which manifold, throttle,ecu and engine harness do I need for my D15b non vtec jdm?

Thank you all.

TomCat39

The JDM D15BB non vtec is the same motor as the USDM D15B2 and D15B7. Same pistons, rods, cylinder head etc.

This engine should have an IACV on the intake manifold that controls idle electronically and then a FITV that controls idle when cold mechanically via coolant temperature.

And then you have the idle control screw on the throttle body.

I believe the OBD2 cars did way with the FITV that is under the throttle body. I would think this is the one that would be "deleted" from the system. I would leave it hooked up to the coolant as when it's cold it's open and lets air pass through. When the coolant heats up it closes the valve.

IACV is on the back of the intake manifold, FITV attached to the bottom of the throttle body.

Does this seem like what you are seeing?

Joan Ventura

I understand... should I leave the Throttle how you say?, or can I swap to one without the valve under the throttle body like this one? Because i don't want to leave things unplugged, I want to do a full restoration.



* My throttle looks like this one...


And my manifold like this, but mine has the IAC valve attached, but it's not connected to the system.. not water or plug.. Even one day when I unplugged the IAC, it has a paperboard blocking those holes to the manifold.


thank you..

mk378

When replacing a bad (worn out our blown up) D series engine for daily driving, it is best to swap out ONLY the engine itself: the block and head. Keep the manifolds and controls that came with the car. That is assuming of course that a previous owner did not swap stuff out.

The valve on the bottom of the throttle body looks like a 3-wire IACV. This is what is used with a OBDII automatic ECU in the USA versions. The manifold would not have an IACV on it. The 2 wire IACV on the manifold was used in manual OBDII EX or OBD1 systems.

So you have two parts (3-wire throttle body and, well, some other manifold) that were not intended to mate with each other. This may or may not be a problem. If the air from the IACV on the TB can't actually get into the engine, it would be a problem.

Also you should go to the "Wiring Guide" sticky at the top of this forum and identify all your plugs by wire colors and make sure they are plugged into the correct things. There is no mechanical interlock to keep for example the 3-wire TPS plug from being plugged into the 3-wire MAP sensor and vice versa. Honda made the bold move of assuming that the people who work on their cars would know what they were doing.

TomCat39

As MK378, it doesn't look like you ended up with the OBD1 setup and instead have one of the OBD2 variants.

My statements are a moot point. Except you have an IACV attached to your manifold and the throttle body you posted a picture of also has an IACV.

I do not think an unplugged spare IACV will cause issues as I believe the IACV is closed by default and is opened with the ECU signal.

I would make sure that which ever IACV system is stock with the car is used (2 wire or 3 wire) and leave the other unplugged. If that means the throttle body IACV is unplugged, I would then put on the one without a valve you posted just to have it be a cleaner install.

I would also check for vacuum leaks and that is the other area that is going to cause idle problems.