EJ20 wiring in L-series, few quick Q's

Pav · Post by **Pav** » Mon Feb 15, 2010 10:06 pm

Hi I have recently aquired an L-series with an EJ20 AWD conversion (from 98 impreza). The motor is wired up and running but I need to get the dash working.

- How would I go about hooking up the fuel gauge, temp gauge, oil gauge?
- How would I get the speedo and tacho to work?
- I can use aftermarket gauges if it makes things easier...
- Also I heard you can wire in a center diff "lock" switch that tricks the ecu or something so you get almost 50:50 drive, is this possible?

cheers I may have missed something but I need to get started on this soon

AndrewT · Post by **AndrewT** » Mon Feb 15, 2010 10:14 pm

fuel, temp, oil - look up the "pin-out" wiring diagram for the ECU. Then just connect the relevant wire from the ecu to the guage.

Speedo - just plug your L series mechanical speedo cable into the speedo socket of the gearbox. The gearbox might already have an electronic speedo sensor in it. If it does, just unscrew it, throw it away and plug the mechanical cable in it's place.

tacho - same deal as the fuel, temp and oil. Just find the correct wire out of the ecu and run it to the guage.

Aftermarket guages won't really be much easier, it's the same deal.

I'm guessing it's the AWD automatic from the 98 impreza? In which case I don't think those are the proper VTD gearboxes. I don't think you can do the "centre diff lock" trick with those....but I am definitely not 100% on my knowledge of these so I could stand corrected here.

YouTube · Post by **El_Freddo** » Mon Feb 15, 2010 10:19 pm

G'day Pav,

The fuel guage should already be hooked up through the standard L series loom.

The oil and temp guages can be wired through the original L series loom - you'll need to cut down an EA82 engine harness that fits the model year wiring of your L series. Otherwise you have to chase wires behind the dash to plugs that are easy to tap the EJ wires from the appropriate senders to the right guage. The EA motor loom trick is by far the easiest.

The speedo - remove the speed sensor on the gearbox. Screw in the L series speedo cable. Done! It will be difficult to do but this is the way to go.

The tacho - you will have to find the EJ's tacho wire from the ECU and tap this into the tacho wire to the dashboard, you'll have to find this too. It can be frustrating but once its done you'll be laughing!

That "diff lock" mod you talk about has something to do with an electronic centre diff in the auto gearboxes. I don't know a lot about it but someone on here will know more. If you have a manual box it can't be done (unless you fit the centre diff from an auto - if it can be done with ease).

Hope this helps

Cheers

Bennie

YouTube · Post by **El_Freddo** » Mon Feb 15, 2010 10:21 pm

Beat me to it AT!

Pav · Post by **Pav** » Mon Feb 15, 2010 11:30 pm

Thanks for the replies fellas this is helping heaps.
So the temp, oil and tacho all come from the ecu? In that case would anybody have a wiring diagram handy?:)

Btw it is an automatic awd, so if anybody has a writeup or if it is even possible to do the center diff lock trick that would be great.
Cheers

YouTube · Post by **El_Freddo** » Tue Feb 16, 2010 12:50 pm

I'm not sure that the oil and temp guage wires come directly from the ECU to the guage, I understand them to be two wires in the ECU harness that connect the senders to the appropriate guages.

Here are the wiring diagrams I used to cut down my harness with, I owe a lot to ben for posting these up:

Ben's EJ wiring diagram scans

I ended up using the L's wiring for the oil warning light and temp guage. For the alternator wiring I used this diagram that Outback Bloke drew up for me:

Cheers

Bennie

Pav · Post by **Pav** » Tue Feb 16, 2010 9:49 pm

Cheers for the help mate, rather than using L wiring I think I will try and tap into the EJ wiring from behind the dash to get to the temp/oil gauges.
So basically do I just get the wires from the gauges and wire them inline into the wires coming from the senders? Sorry bout the silly questions but I need to get this thing ready soon, cheers

AndrewT · Post by **AndrewT** » Wed Feb 17, 2010 2:22 am

no not really....the senders (or "sensors") on the EJ engine are connected to the ECU via the EJ loom. The ECU needs these so it can tell whats going on with the engine. They go into various input pins as part of the big yellow connectors on the ECU.

Some of the pins on the same yellow plugs are OUTPUTS for the dash lights. These are what you want to connect to the relevant guages.

Just need to get the correct pin-out diagram for your ecu and connect 3 or 4 wires and ur done

Gannon · Post by **Gannon** » Wed Feb 17, 2010 5:31 am

If you want constant 4wd, you will need to put a switch inline with the wire to the duty soleniod C. When the switch is open, the solenoid sends full pressure to the transfer clutch. You will need a resistor to fool the TCU into thinking the solenoid is still there.

I dont think it is necessary as the TCU is very smart and automatically sends power when it needs it

Pav · Post by **Pav** » Wed Feb 17, 2010 10:35 am

Ok thanks heaps guys, I think I have enough info to tackle this job, as for the constant 4wd thing, I found a good website which shows how to do it, and I don't know if it is necessary or not but would always be a good option to have in some situations (taking off on boggy sand or uphill etc)

YouTube · Post by **El_Freddo** » Wed Feb 17, 2010 3:05 pm

AndrewT wrote:no not really....the senders (or "sensors") on the EJ engine are connected to the ECU via the EJ loom. The ECU needs these so it can tell whats going on with the engine. They go into various input pins as part of the big yellow connectors on the ECU.

Some of the pins on the same yellow plugs are OUTPUTS for the dash lights. These are what you want to connect to the relevant guages.

Taken that on board - my 1991 Gen I EJ22 has separate senders for the dash guages. Thought this is how they all worked...

Don't worry about asking questions, I asked the same ones a few times over. After you've done it all you'll wonder what you were worrying about!

Cheers

Bennie