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1994 Legacy Crazy Electrical Gremlins


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Alright I'm gonna need everyones ideas/input on this one. I got a 1994 Legacy LSI wagon with a manual tranny in it. I've done some work for this guy and this is the last job I have to do so I can get a 1992 SVX touring. I really want the SVX, I've always dreamed of this car and I really really need to get this legacy on the road.

 

History on the car, he bought it at an impound auction. I'm guessing the car was abandoned because the it wouldnt run. Who ever had it blew #1 rod through the top of the block. After taking a quick glance at it, I noticed the Power TR box was missing (screws down right above the dog bone/pitch stopper) the cam and crank sensor harness connectors were cut out and the coil pack was gone.

 

We replaced the stuff that was cut out or missing. Went to start the car and I noticed no check engine with with key on engine off. I connected the green and black scan connectors under the dash still no check engine light. We are getting no spark no fuel. I went through and replaced Every relay under the dash that I could find, took apart all connectors from the engine back to the dash and cleaned them out with electric contact cleaner.

 

I tested the ECU for power and grounds and it seems to have power/grounds were its supposed to from what I can tell. I dont know what wire is the 12v power supply wire to the ECU though. All Data didnt list the wire, I checked with Chux and he mentioned that it was a yellow/red wire. All yellow wires with a red stripe are hot with the key on. I read up on the board and found that the ignition relay is the blue connector/brown relay up above the interior fuse box, I replaced that along with the green connector/round relay and the red 3 wire connector relay thats behind the fuse box. I'm not sure what relay on these is the fuel pump wire.

 

So after all of this tinkering around (pulled the cluster out checked the bulbs replaced the bulbs, swapped out the cluster) and still no check engine light. so as we were getting ready to tow the car out of the shop I was rolling up the windows and noticed that the power window switches would make the check engine light flicker on and off and make the fuel pump power up. so I tried playing with the buttons and cranking on the car. Still no solid check engine light with Key on Engine off and the engine will still not start.

 

Any ideas on what could have melted together causing the power window circuit to make the check engine light/fuel pump/ecu have intermittent power? There are a few connectors under the dash that are unplugged and I've noticed on all legacy's I've worked on that they are generally left unplugged. There is a big black connector next to the radio along with a dark yellow connector that are unplugged. I'm assuming these are Dealer scan ports for ODB 1?

 

Has anyone EVER ran into this electrical problem where the power window circuit makes the ecu lose power? I cant really find a good wiring diagram for these cars. I had a 1992 FSM on my old computer but the hard drive fried and I lost all the Subaru data I had stored on that comp.

 

If there is a way to disable the power window system, maybe I can get the computer to function properly. Another electrical issue I've noticed that may or may not be a cause/symptom of the no start/no fuel/no spark is the flasher relay for the blinkers and hazards makes a solid buzzing noise when they blinkers are turned on.

 

Ok guys chime in with the ideas. Thanks in advance to anyone answering/posting.

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I would say you have a short or a ground issue.

 

The yellow & black connectors you mention, yes should not have anything connected to them.

 

Here's the 1992 Legacy FSM (engine & electrical

http://www.main.experiencetherave.com/subaru_manual_scans/1992_FSM_(Engine_&_Electrical)/

 

I've got some other various manuals on my server as well.

 

I'd suggest taking a look at the wiring diagrams and checking all the wiring/pins to the ECU to verify they are still wired/functioning correctly.

 

If you do all that, and still nothing, then I'd suggest replacing the ECU.

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Start with the basics.

 

Make sure the Crank Position Sensor and cam position sensor are producing a signal. Is there power to the coils (the coils ground out through the ignitor which is controlled by the ecu).

 

Is the fuel pump running?

 

How do you check spark?

 

nipper

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coil has power, pulled a plug wire off the coil and held it about 1/4 inch from the coil back. I didtn get shocked, or see a spark.

 

Fuel pump is NOT coming on. only power at the fuel pump during key cycling is the fuel gauge power wire.

 

the fact that the check engine light only flickers on/off when operating the power window switch on the drivers side is whats got me stumped....

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I think Legacy777 may be correct about the bad grounding issue for the CEL light problem but it could be a power lead issue. There may be a bad ground to the dash area and the ECU that is causing the trouble. By turning on the window it may be allowing a lower resistance to ground. To prove it you could make a long ground lead and tie one end to the negative battery post and then touch the other end of the wire to places you suspect may have a bad ground, like the dash area or ECU chassis. If that makes the CEL light turn ON while the ignition is ON then you need to check the grounding in that area. It would be a good thing to clean the main grounds at the battery and chassis also.

 

The return side of the light ties to pin 31 of the dark gray connector going to the ECU. Pin 31 is in the second row of wires on one side of the middle of the connector. The wire color is red/green. When the light is supposed to be ON there should be very little voltage on the pin. Hopefully you have something to check for voltage. If you don't have something you need to get at least a test light probe.

 

If the ground isn't the trouble then you need to check fuse 15. It supplies power to the CEL light, along with other things. The power wire to the light in the cluster is red/black and goes to pin c11. Make sure voltage is ok there.

Edited by Cougar
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I'll try the ground deal when we have the car back in the shop.

 

btw there isnt a gray connector going to the ECM on a 1990-94. they use bright yellow connectors. but yeah as far as I could tell all ground supplies to the ECM had ground. didnt do a continuity test because I left my meter at home. I just used a test light to verify grounds. I'll have to check the CEL wire for high or low voltage.

 

I'm kinda pissed that I got conned into working on this car. the deal for me to Get the SVX was to do head gaskets on a EJ25D and then do a engine swap on this 1994 legacy. both which I did but the guy wont give me the SVX until the 94 runs. I'm tempted to tell him to get f#@%ed and just lose the SVX. its not really worth my time to spend 20 hours dickin around with wiring...

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It looks like the info I gave you that came from a '95 manual isn't correct for a '94 model. After looking at one for a '94 it shows that the pin to the CEL light is A16. The pin is just left of the center key for the plug.

 

The power to the light also ties to other warning lights so if they aren't working also then the power from the ignition switch should be looked at. Power to the ECU comes from the Main Relay and ties to pins C3 and C4 of the ECU. Be sure you have power there. If you don't, check SBF-8 and the Main Relay for a problem.

 

Since you aren't getting spark or fuel also I suspect that there is a power connection problem to the ECU causing the trouble.

Edited by Cougar
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well we fingered it out.. I mentioned it to my buddy when we first started but he swore up and down it couldnt be this..

 

Dead short in the battery caused all these issues. Put a new batt in, car fired right up

 

Lesson learned, always start with teh stupiest stuff first

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Back to Basics! ... Well I Was about to Suggest That, 'cos I had that "Flickering" Dash Lights issue when attempting to Run electrical Draining Accesories like A/C or Power Windows on a Car that has a Weak Battery...

I am Glad to Know that you Already Fixed it Up! ... :banana: ... Congratulations!

Pics of the SVX Please! :)

Kind Regards.

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Glad to hear you got it working though I have to wonder about the cure. A shorted battery would mean there would be no voltage available to turn on any light much less crank the engine or read any voltage as you stated you did check. You may find that the trouble comes back later on.

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cougar the car was bought from your neck of the woods.. good old rusty corroded subaru.. its being sold ASAP so we dont have to deal with any new issues from corrosion. I'll get pics of the SVX tommorow if its not cloudy. we are only having 4 hours of sunlight right now, so the light is VERY very flat atm. Need a good clear day to get decent pics outside.

 

Im thinking of lifting the SVX 6 inches. been talkin with The beast about making me a lift for it. put a DR tranny in it with a datsun t-case and some off set 31"s... it'll definatly be a "rare" subaru.

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