ea82t 4 plug computer probs

[kiwibrat]

hey all, having a bit of a problem with geting my motor to run. Just did conversion on my brumby (1987 4 plug ea82t)

The first computer i tried (the one that came out of the same car as the motor) fires the injectors flat out without even cranking engine, just when powered up. Also the fault code light flashes flat out at same speed as injectors

After checking wiring was correct, i swaped computers for a sprare one i have. This one did nothing at all (doesnt light up or anything)

I tracked down another computer and put it in, this one lights up but doesnt give me anything (no ignition pulse or injection pulse) does show fault code 13 sometimes witch is crank angle reference, ive checked out crank angle sensor witch apears to be fine, gives a good signal out.

What i want to know is if all the 4 plug computers are the same and are all compatable??

Is there a difference between auto ecu and manual??

Is there anything im missing??

Any help would be much appreciated, thanks, Andy

[H-top]

I do not think that there would be a differnxe auto to manual because
the auto is not electronically controlled.

All 4 plugs should be the same if the year is the same.

I do not have the wiring s diagrams for all years unfortunately.

[H-top]

I do not think that there would be a differnxe auto to manual because
the auto is not electronically controlled.

All 4 plugs should be the same if the year is the same.

I do not have the wiring s diagrams for all years unfortunately.

Strike me down fellow members where I may be incorrect

[Gannon]

Yeah all 4 plug computers are the same.

The injectors have 12v supply when the ignition is turned on, and the ECU grounds them to make them fire.

Seems like there is a short in your ECU


But it makes me think there is an underlying issue if other ECU's arent working either

[T'subaru]

My ea82t's use transmission specific ecu's. '89 and '90 models
spec codes to identify with out knowing the part numbers

01 MT 49 states and Canada
02 MT California
03 AT 49 states and Canada
04 AT California

Id pull numbers but im away from home for the week. We have compared ecu pin outs and part numbers on this forum in the past and if I recall right we found the US info is the same as AU. Hope this helps.
Cheers, Mark

[Gannon]

Yes there are differences between manual and auto ECU's, but its mostly in the software.

I think the rev limit may be a little lower in the auto and manual ECU's have a neutral switch, which does something with the idle speed/mixture. I think it was 89 models also had a 4th gear switch, which in some markets changed boost and mixture settings for overtaking.


(the above information is only what ive picked up off other forums and has not been verified by a FSM)

[steptoe]

search in here should come up with a typed out 4 plug ecu pin code in a comparo between three plug and four with input by myself and Discopotato03.

LTurbo runs a 4 plug I think, that had a 4EAT electronic tranny AWD that had its own TCU.

With my three plugger I did not change the ECU pin connection when gone from auto to manual.

Andy, maybe make a new thread asking 4 plug ECU owners to drop ECU and give you the part number they have to compare with yours.

Good to see you are many steps closer than meself to a Brumby with an EA82T.

PLEASE , have you got a pic of EA82 in the engine bay showing clearance of chassis rails? A point of a little discussion in here from time to time

Where are you getting your details from to be able to check all wiring is correct?

Jonno

[discopotato03]

You need to get two signals from the crank angle sensors in the distributor , one is the reference pulse (tells the ECU that the crankshaft and No 1 piston are approaching top dead center on the compression stroke) and the cylinder pulses .
Computers of this era need that reference pulse also as a crank/engine speed signal and they are not supposed to inject any fuel without it - anti flood strategy .

Must have spark , you can try getting the dizzy cap end of the coil lead and sitting it close to an earthing point without touching . When cranking the engine you should get a visible arc and a snapping noise . If so then you know that the computer is getting CAS signals and the transistor is switching the coil on and off .

First test the positive side of the coil for ignition switch on power and if you have a smart test probe like Coxy has you can probe the negative side to see if its being switched on and off . If its not you won't get any spark and the computer shouldn't be injecting any fuel .

From the factory 87 WSM it says to disconnect the injector connector which I gather means the engine loom to body loom one .

Unplug the CAS/distributor , I think four wire round plug .
Wire colour codes are (R) Red , (B) Black , (W) White , (BR) Black with Red trace .
Switch ignition on but don't crank .
Check voltage at (R) - should be greater than 10v .
Ditto (B) - should be greater than 4v .
If so reconnect CAS .

Disconnect two pin plug from the coils power transistor .
When looking into the open end of this plug I think the horizontal female terminal connects to the (BW) black with white trace wire which is the ignition on power supply and runs back to fuse 11 in the fuse box .
the vertical female terminal connects to the (WB) white with black trace coded wire and runs through the loom to pins 37 and 40 of the ECU .

The WSM says to turn the engine over slowly by hand and you should get voltage repeats of 0v and 5 v logically at the (WB) wire .

From what Steve's tried to teach me over the years its mainly the things plug into the looms on a std car that gives problems with EFI systems of the era . Unfortunately when you graft all this stuff into a different car you don't know of any pre existing issues the system may have had .
The most successful conversions seem to be when a correctly functioning system is taken from one car meaning a matching set and fitted to another . This way you know that all the components including the loom are good and provided you add the necessary power and earths it should start and run normally .

If you have no luck you may have to import a mechanic thats familiar with L Series EFI or cars from that era , they can quickly check a few vitals and ascertain what isn't functioning .

Hard to tell without being there but it sounds like there is some sort of issue with the CAS or the coils power transistor and either could be because of wiring issues .
For the record are you using a complete std loom or has it been changed in any way ?
If it was an auto loom it should have an inhibit switch somewhere near the trans tunnel and you are going to have defeat that .

I don't have any personal experience with Subaru four ECU plug systems because my RX Turbo has the earlier more basic three plug with conventional distributor system . Its not quite as flash as the later one but at least it has two separate (EFI/conventional distributor) systems and can be tested separately .
If anything the later system is simpler hardware wise but everything has to be able to talk to the computer so it can generate the correct output signals to the injectors and coil transistor .

Lets know how you go , cheers Adrian .

[kiwibrat]

thanks for the advice guys, so is it safe to say that all the 4 plug computers have the same pin outs?? i noticed that the insides of the auto computer is different to the others i have. thanks again

[T'subaru]

Heres a 4 plug ecu pin out from my '89 fsm.
Cheers