Jump to content


Welcome to Ultimate Subaru Message Board, my lurker friend!

Welcome to Ultimate Subaru Message Board, an unparalleled Subaru community full of the greatest Subaru gurus and modders on the planet! We offer technical information and discussion about all things Subaru, the best and most popular all wheel drive vehicles ever created.

We offer all this information for free to everyone, even lurkers like you! All we ask in return is that you sign up and give back some of what you get out - without our awesome registered users none of this would be possible! Plus, you get way more great stuff as a member! Lurk to lose, participate to WIN*!
  • Say hello and join the conversation
  • Subscribe to topics and forums to get automatic updates
  • Get your own profile and make new friends
  • Classifieds with all sorts of Subaru goodies
  • Photo hosting in our gallery
  • Meet other cool people with cool cars
Seriously, what are you waiting for? Make your life more fulfilling and join today! You and your Subaru won't regret it, we guarantee** it.

* The joy of participation and being generally awesome constitutes winning
** Not an actual guarantee, but seriously, you probably won't regret it!

Serving the Subaru Community since May 18th, 1998!

Guest Message by DevFuse
 

Photo
- - - - -

"Electronic Brain" (ECU) replacement


  • Please log in to reply
7 replies to this topic

#1 revbill

revbill

    USMB Regular

  • Members
  • PipPipPip
  • 65 posts
  • Redmond

Posted 09 September 2005 - 04:12 PM

Hi, all. I'm a frequent lurker (and information user) but I don't post much, thanks to the hefty archives on this site, which are better than any repair book I've ever seen.

I'm a contractor at Microsoft, and there's a '91 Loyale someone's looking to get rid of cheap in the Microsoft classifieds. In the ad it says it needs an "electronic brain." I e-mailed the person with the car, and they said their neighbor, who is a mechanic, came up with this diagnosis when the car died and wouldn't start. I'm not sure if it turns over or not, but it sounds like it might.

My question for you all is, first of all, has anyone looked at this car? It's been in there a while, and I wouldn't be surprised if there was another subaru maniac working at MS.

My other question is: what should I look for if I go look at this car? I was going to bring a battery and see if it turns over, then go from there. What would the symptoms of needing an "electronic brain" (I love the way this sounds--great band name) be? It sounds like if this is really the problem it would be pretty easy and cheap to fix, but would there be a risk of blowing a new ECU?

One theory I have is that the timing belt broke, and the well-meaning neighbor was explaining that with these modern cars, everything's controlled by a computer, so they're hard to work on. It doesn't make sense to me that an ECU would blow on a perfectly good car, but who knows.

Does anyone have some advice for me on this? I appreciate all the collective help, past and future.

#2 zyewdall

zyewdall

    Subaru Master

  • Members
  • 2,132 posts
  • Ward, CO

Posted 09 September 2005 - 04:23 PM

I've never heard of the ECU dying, unless the car is struck by lightning or something. Or if you try to jump start it and hook the battery up backwards. I suspect some sensor or such went bad, and the ECU won't let it start now.

But, if you do need a new "brain" for it, I'm parting out a '91 Loyale right now. I already used the engine, but no one has taken the ECU yet... That would be pretty cheap to mail I suppose. But where is it in this car? I don't see it under the hood anywhere. Maybe under the dash?

#3 Snowman

Snowman

    Midnight Passenger

  • Members
  • 3,538 posts
  • Haines

Posted 09 September 2005 - 04:28 PM

Generally, if the check engine light comes on with the ignition on and the engine not running, the computer is okay. Your timing belt hypothesis is very likely to be true, and can be verified quite easily. The same procedure will also allow you to check for another common problem, which is the distributor rotor set screw coming loose.

Use a phillips screwdriver to remove the distributor cap (it's held down by two screws). Inspect the disty rotor to see if it's firmly held in place and unable to rotate on the shaft. If it can rotate on the shaft, then its set screw fell out. Reinstall the screw with some loctite and you should be good to go. If the rotor is firmly held in place on the shaft, crank the engine while observing the rotor. If the rotor doesn't turn with the engine, the driver's side timing belt is gone (that's the one that usually fails first). Replacing the timing belts is a simple job on these engines.

Good luck!

#4 Snowman

Snowman

    Midnight Passenger

  • Members
  • 3,538 posts
  • Haines

Posted 09 September 2005 - 04:29 PM

I've never heard of the ECU dying, unless the car is struck by lightning or something. Or if you try to jump start it and hook the battery up backwards. I suspect some sensor or such went bad, and the ECU won't let it start now.

But, if you do need a new "brain" for it, I'm parting out a '91 Loyale right now. I already used the engine, but no one has taken the ECU yet... That would be pretty cheap to mail I suppose. But where is it in this car? I don't see it under the hood anywhere. Maybe under the dash?


It's held to the bottom of the steering column by three nuts.

#5 zyewdall

zyewdall

    Subaru Master

  • Members
  • 2,132 posts
  • Ward, CO

Posted 09 September 2005 - 04:36 PM

Thinking about it, the timing belt sounds the most probable. They do fail exactly as Snoman says -- drivers side going first. And since the engine doesn't self destruct, it just stops running and you don't know why... Till you check the distributor. On mine I could also tell it was cranking weird, because it didn't have compression in one side any more.

#6 revbill

revbill

    USMB Regular

  • Members
  • PipPipPip
  • 65 posts
  • Redmond

Posted 09 September 2005 - 04:44 PM

Great, thanks everyone. I'll check the distributor and the timing belts when I go there. I thought it sounded strange that an ECU would go out. I'll be sure to ask if it was hit by lightning, or some sort of secret government death ray.

And zyewdall, I'll let you know if I need that ECU, thanks.

#7 calebz

calebz

    Andys Coupe killed my cat

  • Administrator
  • 7,547 posts
  • Tacoma

Posted 09 September 2005 - 05:48 PM

I had an ECU go up in smoke a couple years ago.

CEL wouldn't come on, got no spark and the fuel pump quit.

With the diagnostic connectors connected, the fuel pump should cycle off and on.. mine didn't. that was my first clue that something was not right.

#8 gunslinger

gunslinger

    USMB is life!

  • Members
  • 167 posts
  • Gold Bar

Posted 09 September 2005 - 07:00 PM

Great, thanks everyone. I'll check the distributor and the timing belts when I go there. I thought it sounded strange that an ECU would go out. I'll be sure to ask if it was hit by lightning, or some sort of secret government death ray.

And zyewdall, I'll let you know if I need that ECU, thanks.


REVBILL,

if you decide to not pick the car up, call me and ill take it off the guy's hands. :brow: 425 478 8119. and if you need an ECU go to pullapart in lynnwood. ECU's under the dash bolted to the steering column.




0 user(s) are reading this topic

0 members, 0 guests, 0 anonymous users