The AUSubaru.com.au Forums

Stripping down the wiring loom, i have come across 2 pins on the ecu that i have no idea what they do. They are B56.7 and B56.8. the description for both is "Select Monitor (Rx)" and "Select Monitor (Tx)" respectively. does anyone know what they do, and are they critical for running the engine?

cheers,
adam

I belive they go to the diagnostic plug that Subaru use to find faults within the ignition system. I always remove the plug and insulate them wires. The way i look at it is... if your doing your own conversion then you can'r afford Subaru to fault find on your car.

The normal way of fault finding with the engine light will still work however.

Short answer is No you don't need em, and to cut them and insulate the wires.

Dave

cool that clears it up. ive cut out everything except for all the engine sensors that came from the ecu. looks like ill have to make a relay loom as well.

1 more question, theres 2 wires, both Green/white, going from one of the 3 main engine connectors, to an instrument cluster connector. do you know what these are?
cheers

Have you found the Oil light wire and the Temp Guage wires??

They both come off the engine harness and go to the cluster.

Don't confuse the temp sender wires to the ECU and the Temp sensor wires for the guage... they use different senders on the motor... hence different wires.

Dave

If you have i think the speed sensor wire and the engine light wire run to the cluster also.

I hope this narrows it down.

Dave

What ever you do dont cut the temp pick up sensor for the ECU, the engine will run with black smoke out the back all the time.

As said the Temp and oil light wires are different to the ECU ones. You can get away without a speed sensor if you dont have one

oh ok thanks. i think ive got the oil and temp wires, but thats it. there are only 2 wires running from the engine connector to the cluster. at least i know what they are now. my diagram didnt show them in there.

I think your mad cutting the select monitor wires. leave that plug there - if you ever need to diagnose the thing (with a computer) you need that connector

Subarino do you mean to say that I can't take WackyBug in to Subaru to have them diagnose it??

j/ks

ok ive got the loom into 2 parts now, the ecu sensor wiring and the rest of the loom, relays/alternator plug/radiator fans are all seperate. now do i use the alternator plug and fuses from the ej loom or just hook the alternator into the existing EA plug? im aware that it still needs the self shut-off control plug which will come off the ecu.

cheers
adam

haha

you dont have to go to subaru to make use of the select monitor port, I sell data cables that let you do this with a laptop

vincentvega wrote:I think your mad cutting the select monitor wires. leave that plug there - if you ever need to diagnose the thing (with a computer) you need that connector

hehe when I was doing my loom...

"Diagnostic port Nah, don't need that!! *snip*"

3 months later I had two wires joined back onto it! oops.

ive completed the wiring loom now, im just a bit confused as to how the ecu gets its grounding points? where does it pick up the negative from, and can the sensor grounds and all the other grounds be bundled together?

cheers,
adam

yeah i would make all the ground points to the same spot. Use a very very good bolt on the body that can not fail. (steering rod bolts are good on the drivers side) This will avoid ground loop problems.

And yes i would put the grounded sheild wires to the same point.

Im not sure what u mean by not knowing how the ECU is grounded. I had a quick look at a wiring diagram and there should be atleast 2 wires on the ECU that should be grounded for the ECU and for the sensors.

Dave

oh ok, so those green and white connectors right next to the ecu on the wiring loom are grounding points? are these the only 2 that need to be grounded, because in my wiring diagram it tells me that 6 of the pins need to be grounded yet there is no provision for it like bare ends or ring connectors. makes me wonder if it gets all these grounds from the engine connectors or whether i have to put them in.

The grounding wires SHOULD be black with a red trace and there should be quite a few coming from pins from the ECU As said band them together and bolt them to a good spot on the body preferably nude metal. I always put in 2 earths in a harness that way if one is problem or is cut for what ever reason the engine will still run.

The Green and white connectors if they are terminated sound like they are for the check functions.