Need guru help with a59 rewire

[daplatano91]

So I'm in the process of doing a wire tuck on my car and have been removing anything not involved with running and starting the engine. I have run into a snag though. By mistake I have cut the A59 connector out of the harness. From what I've been reading without this connector the car will not run. Does anyone know how this wire is run and what can I do to put it back in the harness. It is the engine speed adjustment connector. Any help would greatly be appreciated.

 

[19Eclipse90]

I'm not completely sure that holds true for 1Gs as it does with 2Gs. The engine speed adjustment connector is a single wire in 1Gs whereas on 2Gs it has two wires going into it that must remain joined together.

Whatever that means, right?

Preface: The material below denotes the connectors using http://www.dsmtuners.com/forums/articles-electrical-wiring/412841-1990-engine-control-wiring-harness.html article as a guide and are likely different from what is actually found in a 1990 electrical service manual.

Basically on a '90, A-59 runs back to a group of wires just before the C-58 connector. I haven't peeled the tape back from there just yet, but the main gist of it is there's three other wires coming out of that bundle. One is a ground (thin black wire) running back to the location by the ECU, one runs to pin 5 (white wire) on C-58, and the other runs to the top pin (single white wire) of B-00, the noise filter connector; it is of note that this last one starts from the bundle as a thick black wire with white strip and only near the B-00 end does it magically turn into a single white wire.

Assuming the C-58 connector holds a similar function as the '91+ models, this white wire at pin 5 is the tach signal and will run to the gauge cluster which suggests that it is connected with the black wire with white stripe. As mentioned, the thin black wire goes to ground.

All that being said, it appears that removing A-59 would be similar to removing the noise filter that connects to B-00 (not necessarily B-00 itself) in the sense that it would have no effect on the engine starting/running. Steve posted this which, if I interpret it correctly, seems to confirm what is presented here: http://www.dsmtuners.com/forums/tuning-engine-management/335519-tacho-interface-swap.html#post151872567.

Since I do not have a dash harness or the '90 diagrams to look at, I can't be 100% certain. If it makes you feel any better, '91+ models could run without the engine speed adjustment connector as all it does is tap into a wire running between the coil pack and the power transistor.

 

[daplatano91]

Ok great after looking over the wire diagram and double checking the plug itself I figured that the same rule did not hold true for the 1g as it is on the 2g because it was only a single wire.

On another note I would hate to start a separate thread for such a simple question but when wiring extra injectors can I simply tap the power wire of the respective primary injector then run the signal wire to the correct aem pin?

 

[steve]

No. keep in mind that each injector on a turbo car has it's own injector resistor. Running two injectors off the same resistor would change the behavior of the circuit and you might not be able to provide enough current to open both injectors. If you're going to run another set of low impedance injectors you'll need to verify what the AEM drivers are configured for and perhaps run another set of injector resistors to feel them.

 

[daplatano91]

The injectors I'll be running are high impedance does this make a difference?

 

[steve]

All of them?

Any that are should be wired without the resistors (direct or using a resistor pack bypass) to the power source.

 

[daplatano91]

So in other words your saying that I should get the power for the secondary injectors from the power just before the resistor pack or directly from the 12v in off the ecu

 

[steve]

I'd wire them to the same place where the stock injector resistor pack currently gets it's power. That's a branch off the output of the MPI/MFI relay.