FHS

iTrader: (2)

So, I had an issue with an ECU wire breaking off at the connector:

https://www.miataturbo.net/forum/t28863/

Fmowry offered to send a couple of wires and pins to me since he was working on his NB. There seems to be an issue with ECU plug pin compatibility between the NBs and NAs. Does anybody know of any other plugs that an NB has with pins that might fit the NA ECU plug?

Thanks!!

Fred

Joe Perez

iTrader: (8)

I can't help with the pins specifically, but I do feel your pain since this happened to me when I had the stock ECU still in the car.

Since I needed it fixed right away, I took the wire that had broken off, stripped it back a little, and crimped a common 1/4" terminal onto it. I then took a 6" length of wire and crimped a mating terminal onto this. Lastly, I removed and opened my ECU, located the pin on the connector which corresponded to the broken wire, and soldered my 6" pigtail onto the underside of the board in the appropriate spot. There's plenty of room to run a wire out of the ECU case in the gap between the lid and the connector.

Which wire is it that's broken (pin number and color)? It might be one of those that isn't actually all that important, of which there are a surprisingly large number.

FHS

iTrader: (2)

Hey Joe,

I believe it's 2O. For certain, it's one of the wires that gets cut to install the EManage Blue, on the ECU side.

I'm not comfortable enough with my skillz to crack open my ECU just yet, but definitely thanks for the suggestion. We'll see how the great ECU pin search goes first!

In case it does come to that, if I open up the ECU case, will the point where I solder the wire to be obvious with plenty of room for a sloppy soldering job, or it will be something i have to search for requiring a nice, clean, precise soldering job?

Joe Perez

iTrader: (8)

Pin 2O, eh. A red wire with a sleeve around it? Yeah, that's an important one- it's the AFM signal.

As to small & precise vs. big & sloppy, I guess it depends on your point of view. I'm used to working on boards that contain surface mount ICs with hundreds of pins, using 30ga wire, ultra-fine tools, and a Leica stereomicroscope. So I'm a bit jaded.

In all honesty, however, the inside of an NA ECU is a pretty easy working environment. Things are loosely spaced out, especially around the connector, and it's all through-hole. In fact, I'd say that the spacing of parts in a '90-'93 ECU is even greater than in a Megasquirt.

Assuming that you have a clean, straight tip, some .032" rosin-core solder (forget the fancy stuff, you want plain 'ole 60/40), some 22ga stranded wire and anything resembling a steady hand, it's actually a pretty beginner-level repair. If you don't have an iron, go to Radio Shack and buy One Of These. None of those irons are particularly awesome, but they're cheap and will be good enough for what you're doing here.

FHS

iTrader: (2)

Hey Joe, I realized I had these links to the pics from Kags old Pictorial guide to the Emanage install.

Is this what you were talking about when yo usaid you soldered the wire to the appropriate ECU pin?

http://www.automotiveexpression.com/.../emanage29.jpg

If so, instead of running the wire through accross the length of the ECU, you just looped it back to stick out towards the harness?

Joe Perez

iTrader: (8)

Same basic concept. I made the connection on the underside of the board so I didn't have to fiddle around trying to solder a wire in-between pins. But yeah, just tacked a wire to the pad on the board where the pin went and then ran it right out the back below the connector.

FHS

iTrader: (2)

Ok, so I'm looking at parallel rows of contact points where the pins are soldered to the board. If I flip the board over, I would just solder the new wire to the other side of the corresponding contact point, correct?

Joe Perez

iTrader: (8)

Yup.

I honestly can't remember if 2O is on the top or the bottom. If it's on top, you can solder to the back of the pin itself just like in the picture you linked to. I did it on the bottom because the wire I broke was on the lower row of pins, and thus not easily accessible from the component-side of the board.

FHS

iTrader: (2)

Fixed and running.

Thanks again Joe. 2O is on the top row, but it was just a lot easier to solder the wire to the back of the board.