Zaphod

Hi guys,

I have a thread going on with my 1996 (90bhp) Euro 1.6 to VVT swap attempt.
Here: https://www.miataturbo.net/engine-pe...uro-car-72134/

Now I re-wired my MS3 + MS3x (DIY Frank's PNP style) from my 99-00 car for the 1996 wiring (which is nearly identical to the 1990-93 wiring, apart from already being sequential injection) according to this schematic:



Now I need some help about the alternator wiring.
I do have in fact an spare 1.8 94-97 alternator here - just in case.
But as I do already have a working alternator circuit inside my MS3, I would like to check the possibilities to use it, but as I am no electronic expert I need some help.

Here is the alternator wiring on the 1996 car:


Here is the wiring on the 1999+ cars:


I have the field wire on the "spare" 16pin connector on my MS3 - now I need to pull a wire and wire it to? (My guess would be the W/G - wire on the 96 car? - Is this correct?)

P.S.: I have no problem if you tell me that I am stupid an should do things how they are always done - aka swap in the old internally regulated alt...

Thanks

NiklasFalk

iTrader: (1)

Have you checked the connector on the alternator?
The connector for an alt with internal control is different (go figure).
Your harness have simply the connection to the charging light in that connector, not something to the ECU which will enable connection to field control.

A 94-97 alt must be the easiest choice (connector might even be the same).
Sell the NB alt.

Braineack

iTrader: (62)

I think he can do what he's talking about, But I think it would require fussing around with the wiring at the connector.

Right now Here's what you have:
What you'll need to do:

Eunos91

resurrecting an old thread, I wanted to clarify/ask a few things.

I'm in the middle of a VVT into 91 NA swap myself. My ECU is a MS3-Pro using Westfieldmx5's custom board. It's made for a 90-93 MX-5 and unses the original ECU connector.

I want to use the internal alternator control circuit that I still have to solder to the board. Once I'm done building the circuit, how do I connect it to my ECU? If I understand Braineack correctly, I have to
- run the White/Green wire (99-00 wiring harness color) from the 99 alternator to the F_Out pin at the ECU, and
- run the White/Blue wire (99-00 wiring harness color) from the 99 alternator to the 12V pin at the ECU

But since my 90-93 pinout doesn't have a F_Out pin, i can randomly pick on. In my case, I could pick connector pin 1D of the 90-93 ECU connector, run a wire jumper over to the 99-00 side of the board and connect it to the hole 1O of the not-installed 99-00 ECU connector.
1O should be connected to the internal alternator circuit of the board, right? I guess so, because in the 99-00 pinout the pin 1O (GY/R color wire) is labelled as "Alt. F_Out"





yellow jumper wire to get alternator F_Out from 1O (99-00 connector) to unused pin 1D at 90-93 connector






1D (W/G) seems to be free, ready to be the future Alt. F_Out pin




Please be kind to me. You're talking to a mechanically skilled guy who still has to get comfortable with electric circuits

Braineack

iTrader: (62)

tap any white/red wire in the engine bay for 12v.

I'd send F_OUT to 2X to the purge valve solenoid wire.

1D goes to the diagnositcs connectors. although you could tap B+ right there as well for your 12v.

Eunos91

Thanks a lot!

Why not hook up the 12v wire from the 90-93 alternator connector (on the harness side) to the corresponding pin of the 01-05 alternator?

... hm I originally wanted to use that wire for the VVT signal. So I'd have to run an extra wire from the ECU, either for VVT function or alternator function.

Would that leave me with a non-functional battery warning light?

Braineack

iTrader: (62)

whoops i was combining the concept of adding VVT and alternator.

ignore me. too early. ill review again in a bit.


if you dont have the alternator yet, I'd go for an internally regulated 94-97 one over the NB alternator.

EDIT: reread, what youre doing looks good. Id' still just recomend using a 94-97 alt over an 99+

WestfieldMX5

If you're going to install a VVT engine, don't forget to remove the tps resistor you have on the board!
The yellow wire to the 99 side is correct. The 2 yellow jumpers in the alternator area are correct as well. Choose software when you want hardware

Eunos91

Thanks Frank. TPS resistor is already removed, TTL to R232 circuit installed, internal bluetooth module installed. Really like your board, although i still have to figure out all the possibilities,... Believe it or not, I own exactly this example of your PCB pictured above.

While you're here, could you quickly answer two questions please:
- for sequential injection i desolder the two jumper wires and connect "Inj A middle hole" + 2U hole // "Inj B middle hole" + "Y // Inj C m.h." + 2Z // "Inj D" + 2V, right? (plus using the correct pins at the ECU connector of course)

- do i still have to install a jumper wire at the AFM connector to make the fuel pump work? Or is it already taken care of by having the jumper wire installed on the board at JB8?

- how do I get the internal BT module connected to my laptop for the first time? I suppose it won't simply be available when I power up the ECU?

WestfieldMX5

Correct about the injector jumpers. And indeed, you'll have to rewire the 4 injectors for the correct pins on the connector)

There's 2 ways to make the fuel pump work:
1. use the jumper
OR
2. remove st-sig fuse and build the active fuel pump circuit what you appear to have done

Is this a BT that I supplied? If so, it is already programmed. If not, you'll have to program it according to the manufacturers manual.

Send me a PM with your email address and I'll send you some setup info about my board.