no spark, no power to the ecu

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damnsubi
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no spark, no power to the ecu

Post by damnsubi »

my dad was given a 91 legacy and it won't start. i have checked all the fuses they are fine. there is power to the coil and igniter but no pulsing power to the other terminals,so i looked up a shop manual online and tested the wires at the ecu. there is power to the yellow wire but not to the three yellow wires with the red stripes. i tried it with the key on and on start and off no power. and i didn't hear the ign relay click either. i changed the ecm because the old one was smelling burnt. the car ran fine then the previous owners shut it off for a few months and it wouldn't start. so they gave it a tuneup and changed the coil pack then gave up on it. now it is my problem. i like where they put the relays. smooth move subaru. working under the dash is not for people with big hands. i don't see a brown relay up above the fuse box. and the ecm is on the drivers side not the passenger side like the haynes told me. i am 6'2" and it is difficult to crawl under the dash. the fusable link is fine. could it be the ign relay? i am getting stumped. :( i also changed the crak sensor and the cam sensor with used ones. the old crank sensor was dented on the bottom.
Legacy777
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Re: no spark, no power to the ecu

Post by Legacy777 »

Welcome to the BBS.

Connector pins B48 2 & 13 are the power supply wires to the ECU. They are yellow with a red stripe. If you don't have power at those pins then yes try verifying power from MB-3. The wiring is kind of screwy because the ignition switch trigger is from the ECU, but ignition relay feeds power to the ECU. So make sure all the ground & power leads are correct.

I've got pictures of the various relays from my 6spd swap. Check out the description for what the picture is referencing.

https://main.experiencetherave.com/suba ... index.html
Josh

surrealmirage.com/subaru
1990 Legacy (AWD, 6MT, & EJ22T Swap)
2020 Outback Limted XT

If you need to get a hold of me please email me rather then pm
damnsubi
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Posts: 7
Joined: Fri Jan 25, 2019 4:44 am
Location: pine city washington

Re: no spark, no power to the ecu

Post by damnsubi »

how am i suppose to get to the ign relay without taking the dash apart? i cannot even see up there let alone fit my extra large mitts up in there. is it above the fuse box inside?
Legacy777
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Re: no spark, no power to the ecu

Post by Legacy777 »

Yes it's above the fuse box and pretty tight in there. My suggestion would be to try and follow the diagrams to see where the wiring from the ignition relay goes and then test the relay/wiring at a more convenient spot if you can.

These 90 Legacy wiring diagrams would be applicable to your 91.

https://main.experiencetherave.com/suba ... agrams.zip

I replied to your post in the service manual thread about you needing to download the file, unzip it, and then use any free pdf viewer.
Josh

surrealmirage.com/subaru
1990 Legacy (AWD, 6MT, & EJ22T Swap)
2020 Outback Limted XT

If you need to get a hold of me please email me rather then pm
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