jacobcartmill

iTrader: (6)

i've been looking at my haynes manual to see about adding some grounds to my ecu to get my secondaries to come on and i found that wire 2C has like 4 grounds branched off of it. my question is, like the title says, whic plug and which pin is 2C?

haynes manual says its brown with a black stripe, but i see no brown wire with a black stripe.

jacobcartmill

iTrader: (6)

come on people, where are you HAILERS.

jacobcartmill

iTrader: (6)

braawwwwrrr

jacobcartmill

iTrader: (6)

i'm a monster brawwrrrr

10TH_ANNIV_T2

Maybe this will help. According to my 1988 FSM, plug 2 is the middle plug on the ECU. Now, looking at the ECU connector socket (not the harness side), 2C is the second pin from the right on the top. Top right is 2A, bottom right is 2B, and this is uniform across all three connectors actually. Connector 1 is the widest, and located on the right as you look at the ECU. I show this pin to be a ground, and the wire color according to my book is just Black, no stripe. Connector is EM31.

Greg O.

NZConvertible

Regrounding the ECU

HAILERS

These are the plugs as you look into the back of the harness with everything connected up. They read from the far right in a up and down method going to the left as described above./

I think in 88 they changed some of the ground wire colors from brown/black to pure black. 3A and 3G and 2R really should be also grounded. Especially the 3A and 3G.

This will help on some cars. Not all. Its the ONLY thing that helped my 87 n/a. The 86 and the 87Turbo suffered no problems, so I didn't do it to them. As I've said before, I can remove these extra grounds(one lug) and make my 87n/a hesitate in a heart beat at 3800. Even with less than .2ohms b/t the battery neg post and the engine. I'm convinced its in the harness where several ground wires are spliced together. Probably a cold solder joint. Mazda probably offloaded the harness work to Korea back in the eighties.

jacobcartmill

iTrader: (6)

thanks hailers, just what i was looking for.
damn, i need to get a FSM

dmcrx7

Dug up from the dungeon, I know, but the link is mentioned in several threads and no longer works, anyone have a working link?

jacobcartmill

iTrader: (6)

almost 2 years old

dmcrx7

the one nzconvertible linked no longer works.
Is this on fc3s pro or somewhere else too?

NZConvertible

This shows you where the ECU's ground wires are.



All I did was follow the wires to where they joined together, solder another wire to connection, crimped a ring terminal onto the new wire and bolted it to the chassis.

Personally I no longer think this is necessasary if the original ground points are in good condition. All of the EFI system's ground wires go to one point on the engine, and cleaning this connection up would probably be a better idea.

dmcrx7

I was just trying to figure out how far back I had to go to check the connection where they all come together, have already redone all of the grounds in the engine bay.

NZConvertible

It's only a few inches from the ECU.