Good morning everyone.

I bought REDOM ecu from forum member about a year ago.
I didn't install it due to lack of info. about ecu.
Recently, I've been sending emails to RE-amemiya to find out about ecu and I believe it is ok to use according to them.

I did alot of search on REDOM ecu and found out that since it is JDM ecu, there are 4 wires that needs to be cut : AWS solenoid valve, EGR solenoid valve, EGR function sensor, split air bypass solenoid valve.

I was thinking if I pull those pins out from REDOM ecu itself, it should work, right?
I am going to block off AWS tubing to eliminate AWS eventually.
I also saw someone say fuel thermosensor is the main difference between JDM and other ECU pinout.

 

You can also just remove the pin out of the wiring harness,same thing must people do when the install the PFC.

 

Would it effect any if I pull it right now with stock ecu on?
Do I have to worry about fuel thermosensor pin?

 

You can pull them and still run stock ECU, I did that when I was waiting to have my car tune.

 

i would just pull the same 4 pins the PFC people do, works great.

 

Thanks for the info.

 

for bonus points, you could wire your car like a JDM car, and remove the E/L box. the 4 wires on the JDM car go to the e/l box on the us car, because the US car runs out of pins. the e/l box takes the 4 inputs and out puts the one pin.

 

I need to do some studying on E/L Box.
Meanwhile, can air pump be removed with split air bypass valve pin removed?
I would really like to get rid of air pump to free up some space.

Also do I need to do something about EGR before pulling the pin out?

 

part of the e/l box is fairly simple, it takes the 3-4 different electrical loads, and translates them into 1 ecu input. it also takes the error code signal, and as if by magic drives the CEL light bulb. i've asked nobody knows how it works, and it apparently never fails either.

short answer to the air pump question is no, the split air thing barely has anything to do with the air pump/acv system

 

Yes, I used a ROM tuned JDM ECU and did the pin mods like you have to for the Power FC and it works great.

I used a patch harness because I had it- so I did not have to alter ECU pins or pull pins from the harness connector (just cut/insulate wires in the patch harness).

 

Sounds like a very simple job and I want to do it asap, although I want to check AFR before I switch to see the difference.
So lazy to install AFR....

 

i have EGT on mine, and the re ecu is different than stock pretty much everywhere. the EGT is actually smoother than stock, higher at idle

 

I just pulled all the pins and installed afr gauge, now I have CEL.
For stock us ECU, am I suppose to get CEL for pulling those pins?
Would CEL go away once I put JDM ECU in?
I'm assuming E/L unit has something to do with this?

I did some study on E/L unit, sounds complicated.
I'm not sure if I want to go that route like JDM car.

 

before you just pulled the wires out of the harness did you look to see what they did? did you check the codes?

the JDM car has no EGR or AWS, so it will not throw codes for those.

the only thing the E/L unit does is amplify the signal from the ecu to actually run the CEL bulb, as the JDM car does not have a CEL.

 

I'm not sure who you mean by they.
My car was completely stock when I purchased.
I haven't check the code due to sunset.
I didn't have any CEL before all this, so ATM, I highly think pin issue.
I can try to check the code tomorrow after work.

 

part of this is a logical thinking exercise. you just disconnected 4 wires (they = the pins, sorry!) from your ecu, why? do you think those wires did something? if they did do something, do you think the ecu would notice? do you think those wires have 12v with the key on?

 

I'm not quite so sure.
My electrical knowledge is very weak.
I did go for run to see the afr, the car ran great.
I can check the code tomorrow after work.

 

I just pulled all the pins and installed afr gauge, now I have CEL.
For stock us ECU, am I suppose to get CEL for pulling those pins?
Would CEL go away once I put JDM ECU in?
I'm assuming E/L unit has something to do with this?

Yes.
Of course you will get check engine light if you disconnect wires to the US spec ECU and leave the US ECU in there. The ECU is doing its job telling you someone yanked wires out for EGR Switch, Split Air Bypass, EGR Solenoid and AWS System.

> > > > > 3J (JDM rear defroster relay/USDM EGR switch)
> > > > >
> > > > > 4F (JDM not used/USDM split air bypass)
> > > > >
> > > > > 4O (JDM TNS relay/USDM EGR solenoid)
> > > > >
> > > > > 4P (JDM not used/USDM AWS system)

You will not have a check engine light with the JDM ECU and those wires missing.

You disconnect those wires for the JDM ECU because it isn't looking for them as they do not exist on JDM vehicles.

part of this is a logical thinking exercise. you just disconnected 4 wires (they = the pins, sorry!) from your ecu, why? do you think those wires did something? if they did do something, do you think the ecu would notice? do you think those wires have 12v with the key on?

Exactly, I guess we should have just let him search out and study the JDM ECU and USDM ECU pin-outs and reason through this mod as we did. It is dangerous to start modding the FD without being able to think through the entire process.

For instance, before I put the JDM ROM tuned ECU in my FD I sent it to Knightsports to be flashed to what I wanted.

An FD ROM tuned ECU has options for no overboost fuel cut, no redline, larger injectors (so stock size would run lean), advanced timing for use with race gas, etc.

It would be easy to blow your engine putting in an unsuitable ECU!

I am not meaning to harp on you, just trying to impress how important it can be to logically work through this.

 

I've checked the error codes yesterday, and they are indeed those 4 codes : 16, 28, 30, 38.
With AFR gauge installed, I connected the REDOM ecu and drove for test.
CEL went out after installing REDOM ECU.
Idle was smooth, did not see or hear any issue.
AFR stayed similar to stock ECU, so I think I'm good to go.

Before all this ECU swap, I did check with amemiya and they said my setup is ok.

 

oh you heard back from them? good

 

I had to send emails in Japanese.
I guess INUKAI does not work there anymore, since I cannot get any response back when emails were sent in English.

 

Awesome!

Glad you got it working. The ROM tuned JDM ECU is an attractive option since it is so affordable and common.

We just need to get knowledge of this option out there and establish communication with the ROM tuners in Japan to find out what we buy.

Shouldn't be too hard in this communications age!

Another option I would like to see more accessible to FD owners is 8bit to 16bit ECU conversion harness and switching to ROM tuned 16bit JDM ECUs.

 

that seems too hard for me
Anything mechanical, I can deal with but wires....no thanks
Thank you guys for all the help.
Now I can install intake and intercooler to see how my engine reacts.

 

-deleted-

 

my friend had a 16 bit ecu running in his FD, and its a huge upgrade. we are able to make an adaptor harness, although it would be expensive, as the 16bit ecu connector is a bit weird