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Hi All,

I am putting an LT10 into my mates brumby with an EA82T a few questions

The EA is a 3 plug ECU

At the moment who ever did the conversion has cut all but 1 wire from the dizzy and it goes to the coil. I have not taken the cap off yet but I though the 82T's had similar to a crank angle sensor in the dizzy to be used with an ignition modual. 4 wires out of the dizzy goin to the LT10 then out of the LT10 to the Ignition modual to the coil.

Also the TPS on the EA seems to have 5 wires but I can only find 4 wire diagrams.

Lastly the LT10 has crank inputs GND. POWER, Input #1 and Input #2 according to the diagram they should be red, white, green and black but the loom I have from microtech is yellow, red, green and blue.

Any help would be great.

I have used the LT10 before but not on a subi engine.

No time ATM but quickly .

3 plug (ECU) type TPSs have 3 wires from the main rectangular connector and they are for earth and switched by the idle and open throttle contact points .

The 4 (ECU) plug TPSs have two connectors insted of one , the main one looks like the early type mentioned above BUT it doesn't have the open throttle contact points so will only have the idle contact wire and an earth .

The second (round 3 wire) connector on the later TPS is for a variable voltage potentiometer so that the later ECU can tell exactly where the throttles position is and how fast its opening or closing .

Bottom line is if the TPS has only one rectangular 3 pin connector its an early one , if it has two (a rectangular 3 pin and a round 3 pin) its a later type but only uses two of the rectangular 3 pin connectors pins .

Clear as mud LOL .

Hope something got across , cheers A .

Will check Subaru 87 WSM later for wire colours from the Hot wire 4 ECU plugs systems . Also have the early systems diagrams from WSM .

Found time .

Later TPS with two connectors .

Rectangular one . BR - to earth , LW to pin 26 of std ECU .

Round one . B - power supply to pin 16 ECU , R - sensor signal to pin 22 ECU , W - ground to pin 21 ECU .

My diagram shows four of the five above mentioned wires going to a common loom plug , the exception being the BR earth wire from the rectangular TPS plug .

To confuse matters some of the wire colours appear to change on the main looms side of this plug . B becomes BR , R becomes B .



Early or 3 ECU plug cars - 1985-early 87 .

Rectangular plug Pin 1 (LW) Idle switch , Pin 2 (BR) control earth , 3 (GR) full throttle switch .


Later CAS type "distributor" .
These have a 4 pin black round plug .

BR - control unit ground .
B - control unit position signal .
W - control unit reference signal .
R - control unit power supply .

Coil Transister switch used with later system to charge and dump coil .
2 pin plug , (WY) to ECU so it can tell the coil via the transister (switch) when to dump , and (BW) to fuse 11 (in an 87 L Series) which is the power supply . This powers up (fuse box) via the ignitioin switch .

I have a diagram for the early distributors systems layout inc "knock box" but if your going to use it leave it alone .
Just need a negative side coil pulse signal to tell your new ECU how fast the engine is turning (RPM signal) .

If you dont feel like making a complete new engine control loom you can use the factory one but note that the injectors are fired in pairs not as one batch or full sequential ie 1 and 2 plus 3 and four ganged - in the late system .
I'm not sure in the early or 3 plug ECU system , the wires go back to the ECU so possibly they have sequential injection via four injector drivers .

You really only need to run two extra wires for sequential injection and whatever for a MAP sensor if you are using that load sensing system .

Check this first but I haven't noticed injector dropping resistors used in the early system so that could mean that these early ones use saturated injectors and the later ones peak and hold types , basically high current and low current .

Lets know how you go , cheers A .

Thanks for the help, should have stuck with my rotaries. ; )

So I have found out it is a 3 pin TPS no worries there
and the injectors are not a drama if I have to run new wires so be it.

I have the diagram on how to wire up the dizzy using a modual.

But not sure where to get the crank pick up from but if the computer

As far as map sensor that will be the vac line.

So a standard early type 3 plug the computer does not control the advance or retard in the timing correct. So using the map sensor the computer should be able to fire the modual to fire the coil in time.

So really all i need is the map, single out put to the coil and TPS (plus all AUX stuff)

Please correct me if I am wrong and a diagram for the coil and knock unit would be very helpful.

first up just let the dizzy fire the spark, no crank signal to ECU.
I used a Microtech Digi2 with ea82t, basically fuel only control.
For that you need inputs of MAP and RPM at the very least.
You should be able to get it to work without TPS also.

Digi2 did have Ignition output, which I did eventually mod to use, thus able to advance/retard spark by maybe 10deg.

Don't know LT10, does it have individual spark ignition outputs? like x4 or only the one?

As for the wire colors, should be on the diagram supplied with LT10?
otherwise trace the wires to the plug on LT10,
each pin would have a definition.

Thanks Sub

Yeah the LT 10 can be used for seq spark meaning 4 coils or just single fire.

Wire colours not a drama anymore.

The other thing is this computer come off a 4 plug ecu and I am fitting to a 3 plug so that would mean it was using the optical dizzy.

See how we go

Did you get the last owners engine loom with that computer ?

A .

Nope,

it came off a 4 plug ecu that is all I know oh and yeah I have to make it work on a 3 plug set up.

Thanks

I guess that means it's going into an early (3 plug) car .

I doubt very much your aftermarket ECU will talk to the early two switch only "TPS" . Most of them want something like a 0-5V output from a potentiometer so I think you'll probably need at least a later 4 ECU plug systems TPS - the one with two connectors . These are not that hard to find as every later type MPFI L Series has one .
Simplest is to pull the throttlebody which has the TPS on its side off a car in a you pull it wrecking yard and fit it as both units (throttlebodies) interchange .

Cheers A .

Warning , do NOT try to use the TPS of a spider Vortex engine as it won't fit the L TB and turns the wrong way anyhow .

The TPS you need can be found on a camry and lots of late eightys car,s..potenziometer type....
with the 3 plug ecu type dizzy..you will have to use a 1k pull up resister to allow the dizzy to talk to the ecu...as its gives a sine wave...the 4 plug type hotwire ecu and 4 plug type dizzy give,s a logic on off in square wave and can trigger the ecu with no mods...cheers

thanks all,

Yep early 3 plug ecu

I might try and get it going, leaving the dizzy the way it is now, find the correct throttle body and run with that.

The next problem is if the tune loaded for the later 4 plug will run the early 3 plug.

oh well you get that.

So going at it this weekend.

Got a 4 plug dizzy with the optical outputs.
Got a throttle body off a camry TPS sorted
Map side of things easy
Injectors will be rewired to be fired seperatly.