xxxchibixxx

is there a way to tell which 13b is jdm and which is usdm? also can the ecu plug different on the jdm and usdm?

misterstyx69

iTrader: (142)

Depends which engine you are talking about.Try to be specific when asking technical questions.If someone has to Pull teeth to get info they won't post!
Anyways One way to tell is the wiring harness will be routed differently.Seeing the "driver's side" is swapped.

xxxchibixxx

well..i bought the rx7 on monday, the owner said it was swap to a jdm motor and the ecu was swap to a jdm one too, so then his turbo seize up and he said he let the car sit for 3 years, so now i bought it and i'm trying to find out if the harness are plug and play with usdm ecu or does the jdm motor need the jdm ecu to run them?

rexy91

iTrader: (2)

Check your intercooler. If it says 13b intercooled its jdm. If it says turbo 2 then its usdm. Also jdm has less smog stuff.

xxxchibixxx

the thing is that it doesn't have those anymore

diabolical1

iTrader: (3)

why don't you take a photo of the intake/exhaust side of the engine and post it? also, post the code printed on your ECU (N3xx).

RXSpeed16

iTrader: (41)

and tell us what year car/engine you are asking about.

Akagis_white_comet

iTrader: (4)

When requesting assistance, it is customary to post the vehicle's details such as model year and grade/trim level (GXL, Turbo II, R2, etc) in your first post. This prevents misinformation due to responders assuming you have a FC as it is the car that most new owners start out with.

Xxxchibixxx's profile indicates this is for a FD, 1994 to be exact. Therefore, information about the intercooler's text and where the harness breaches the firewall is not pertinent.

On a FD, the engine harness, referred to as the Emission Harness in the Factory Service Manual, loops around the engine bay from the drier's side of the firewall to the passenger side of the firewall. The FC has it exit the firewall on the passenger side only.

ECU numbers for FDs are as follows:
N3Ax: North American/J-spec FD S6 Twin Turbo, 8-bit ECU (N3A1 for 1993 North America FDs, N3A7 for J-spec up to 11/95)
N3B1/3: **North American FC S5 NA Vert (1992 only)**
N3B7: Euro FD S6 Twin Turbo (1/92 to 7/93)
N3Cx: Revised North America FD S6 Twin Turbo, 8-bit ECU (1994 North American FDs)
N3Dx: Revised Euro/North America FD S6 Twin Turbo, 8-bit ECU (8/93 to EOP for Europe, 1995 for North America)
N3Ex: Revised California FD S6 8-bit ECU (1995 only)
N3Fx: FD S7 Twin Turbo, 16-bit ECU (12/95 to 11/98)
N3Gx: FD S8 Twin Turbo, 16-bit ECU (12/98 to EOP)

**I've never actually seen the N3B1/B3 ECU before, but it is in the Parts Catalog for 1992. My hypothesis is that Mazda ran out of N35x ECUs and had to modify some N3A1's for use in the final run of S5 verts, hence the N3B1/B3 prefixes.

Assuming it was a North American build (not a California FD), it originally had a N3C1 ECU. My gut feeling says that the previous owner didn't swap harnesses, but only transferred over what was necessary to make the N3C1 ECU operate the N3A7 Engine. I don't know the specifics of this as my area of expertise is with the S4 FC, but searching the 3rd Gen Section and taking a look in the FSM would get you in the right direction.

Depending on how the swap was done, it is possible you'll encounter a N3A1 or even a N3A7 ECU. If that is the case, I would suggest looking for indications of splicing. Again, this is best examined by one more familiar with the FD than myself.

xxxchibixxx

thanks..i will have to relook at the ecu..forgot to take picture of the engine bay, but i try to start it today and it turns out i have lost compression on one rotor so it's time to take out that motor and find myself a new motor.

F-111a

It had been sitting for 3 years? Did you consider the seals could be sticking?

Rickey89

Best of luck on the car turning over to op

misterstyx69

iTrader: (142)

The car is an 1994 ..so FD.
...NOTE: if you try to post another thread and leave out your car info I can Conveniently just not Post your thread.So I suggest you make it a habit.
3 People asked you.you failed to answer.
If you want to get Quick answers providing Just that Basic info will get you Replies that may help you.
Do not make people GUESS.(see Thread at Top of Section)

xxxchibixxx

1994 rx7 FD3s, engine is claim to be jdm from owner i bought from

xxxchibixxx

i started it the other day..but lost compression on one rotor..so i order a jdm 13b..should be here in a week or so

wthdidusay82

iTrader: (15)

You should of just got a rebuild, there's a good.chance the jdm will have similar problems.

RXSpeed16

iTrader: (41)

That's half the answer. The '95 and newer JDM ecu's (N3Fx and N3Gx) use a different plug. So whether or not the USDM stuff will plug in depends on the year of the engine.

I wish you the best of luck with your imported engine. There are some very unfortunate stories about people dealing with importers. Task #1 when you get it is to compression test it. Ignore whatever promise or guarantee that they gave you.

TRIAD

I've looked and doesn't exactly answer my question

I have a 1991 na

Doing a s5 jspec swap

I have engine harness and drivetrain

My problem is the harness

Could I use a usdm 13bt harness on the jdm engine and jdm ecu?

Should I use my stock harness?

Like I said I'm sorry for bringing up an old thread but I've been looking and my poor FC is just there and I really wanna get her running again

Every bit of info will help and thank you very much

rotarr

iTrader: (4)

Use your stock harness it's the best way to do it,It's basically plug and play with your stock harness with the acception of three wires two for your boost solenoid and one for your knock sensor I just finish this same swap on my 91N/A and she is running like a charm.The three wires you will need is from your White and your Brown connector from on your stock harness which is use as your six port solenoid which is the white one I believe has the BLU/BLA and Black wires which is use as the boost solenoid on the JDM and the Brown connector you only use the thicker Black and White wire from this connector as the one for the knock sensor on the JDM motor and that's it,I will look to get a N370 USDM ECU because the Jdm will not run the engine properly with the N/A harness Aldo some people had luck with some of them but if you send the Jdm ecu to Rtek and get it chip it will run just find you will have couple extra plugs think two with no way to plug in because the JDM engine don't have EGR and AWS on in and you should be on your way with the rite sensors which included S5 T2 N370 MAF,N370 Boost sensor,N370 ECU or an Rtek JDM N374 ECU with a S5 T2 throttle cable and T2 or FD fuel pump,wideband and boost gauge with a Apexi Neo to fine tune your Air/Fuel Ratio because you don't want to be or running lean when in boost on your new motor also I will replace all vacuum lines and injector grommets because you don't want to have large leaks on first start up so see how it goes an let we know hope this helps J.

TRIAD

Thanks rotarr so I guess I can just use mine and save my money and not buy the usdm turbo harness

rotarr

iTrader: (4)

Yes you can my friend and if you need anymore help with anything I will be glad to help you with it and thanks again and good luck.