Hi everyone,

 

I'm new here. We have an old Subaru with repetitive problem, so decided to join the forum to get to the bottom of it.

 

It is a Legacy 1994 Auto with a 2.2L engine normally aspirated. Here in Australia, we call them Liberty.

 

The car has been to the mechanic numerous times with the same problem.

 

Basically, from time to time it refuses to start.

 

Previously months before this event the car would conk out in the middle of the road, mainly when battling a long uphill road. However after pulling to the side of the road, the engine would start again.

 

The car has done 170,000 kms or about 108,000 miles.

 

I believe some of the parts that were changed were second hand, then he manage to get the car started but a week later would fail again.

 

Any help is very much appreciated.

I'd check the Mass Air Flow Sensor. Try to replace the one you have with one you know that works and see if the car continues to act poorly.

Crank and cam sensors are known for causing no-starts on these.

 

You've heard of a MAF sensor causing this before? I've never heard of a no start caused by a MAF, but i'm sure it's possible.

crank angle sensor? usually a problem after the car has warmed up, then wont start, then let her sit for a while and she'll start again

Crank and cam sensors are known for causing no-starts on these.

 

You've heard of a MAF sensor causing this before? I've never heard of a no start caused by a MAF, but i'm sure it's possible.

When my MAF failed, the car wouldn't start or run.

Yeah I'd suggest looking at the MAF sensor as well.

 

What parts have already been replaced?

According to my mechanic, he replaced the ignition coil, crankshaft sensor and the last one being the ignition module that got it started.

 

I asked him about the MAF and he said it won't stop the car being started.

 

So unless one of the parts that he replaced has gone bad again, I have no idea what else can be replaced.

 

We can keep replacing parts one by one but it's already getting a bit expensive here. So far $500 not including the towing and the MAF sensor even for a second hand one is over $100 and he said no guarantee that's the problem, sigh...

Edited December 22, 200916 yr by Conroe

Try downloading this manual http://cid-4ca3c3459aaa7f7f.skydrive.live.com/self.aspx/.Public/1992%5E_legacy%5E_full.pdf

and see what (if anything) it says about diagnosing a No start condition. The manual for my 96 has a section specifically for that, not sure if the older ones will have it or not but it can't hurt to have some extra info.

 

I can't remember the username of the guy who hosts that. But he's a great for putting the info out there for everyone to see! Maye he'll pitch in and refresh my memory.

Muffler bearing

According to my mechanic, he replaced the ignition coil, crankshaft sensor and the last one being the ignition module that got it started.

 

I asked him about the MAF and he said it won't stop the car being started.

 

So unless one of the parts that he replaced has gone bad again, I have no idea what else can be replaced.

 

We can keep replacing parts one by one but it's already getting a bit expensive here. So far $500 not including the towing and the MAF sensor even for a second hand one is over $100 and he said no guarantee that's the problem, sigh...

 

try unplugging your MAF while the car is on, it will shut off.... So improper info from the MAF will cause the engine to shut off. There have been similar cases. Finding a USED JECS MAF should be pretty easy to find.

try unplugging your MAF while the car is on, it will shut off.... So improper info from the MAF will cause the engine to shut off. There have been similar cases. Finding a USED JECS MAF should be pretty easy to find.

 

Hehe... I've got to get the car started first before I can do that. Then being a noob, I've got to locate this somewhere inside the engine bay .

Hehe... I've got to get the car started first before I can do that. Then being a noob, I've got to locate this somewhere inside the engine bay .

 

It's the small box with wires going to it just on the throttle body side of the air filter box.

Hehe... I've got to get the car started first before I can do that. Then being a noob, I've got to locate this somewhere inside the engine bay .

It's too bad you're so far away from me. I have a spare lying around here just for testing purposes.

The mechanic is right, the maf won't cause a no start. They will run rough for a second then the ecu ignores the maf and just uses throttle position and revs to run the car. The crank and cam sensors are the most likely electrical components. All the other sensors the car will run without.

 

Have you checked the fuel pressure and flow though? Changed the fuel filter? Always a good place to start if there are no trouble codes set... which I'm presuming there aren't since you don't mention them.

 

Also...

If you are getting elusive, varying, intermittent codes, or no codes at all, and the car is a few years old....

Pull the ecu and have a look inside. Look for blown transistors(they can explode a piece out of the side of them), burnt resistors, cracked circuit boards, dry solder joints, leaking capacitors, water damage.

Use a magniying glass and inspect every component, circuit and joint.

It only takes a matter of minutes and given the number of things that can happen inside there, and the number of checks you could have to do to track it to there, it's best to do it earlier than later in the diagnostic process.

Ok, where can I find the ecu for the Legacy, underneath the dashboard I presume or behind the glovebox?

Ok, where can I find the ecu for the Legacy, underneath the dashboard I presume or behind the glovebox?

 

under the carpet on the passenger side near the fire wall.

The ecus will be just above the drivers right knee I think. There are two there, a engine and a transmission computer. The engine is the big one.

 

Take the plastic covers that are under the dash and above your knees away. In some cars there are two, one black one that goes right down to the pedals and another coloured one that's more part of the dash.

 

Use a flat bladed screwdriver to lever gently on the wiring plugs one at a time while you depress their little locking tags which are in the centre side of each plug. Then using spanners, sockets and extensions you can get the ecu out. Take out the philips head screws and inspect the internals carefully.

 

It only takes about half an hour to an hour to do it and get it back together and that is nothing compared to the time you can waste looking for faults that turn out to be a faulty electronic component inside the ecu.

 

From the circumstances of your problem, ie, dies when hot and working hard, then comes right fairly quickly when it cools just a little... I'd be suspecting the crank and cam sensors which have a bit of a reputation for doing that. If not them, then the ignition ignitor which is on the firewall would be my next most likely suspicion. It's the nature of faulty electronics to die when overheating, then to come right way before the motor has cooled much at all. Perhaps the mechanic used a second-hand ignitor?

Here's a pic of the MAF sensor (minus the stock airbox)

 

 

 

Here's a pic of the ECU

 

In australia aren't they 1 year ahead ? So a 94 for them is a 95 for us.

In australia aren't they 1 year ahead ? So a 94 for them is a 95 for us.

 

That's a good question, I remember Subaru used to put us ahead before other countries but since when I can't remember.

 

Ok here's another data that may be useful, a few years ago the car had a pretty bad front end damage that requires the removal of the engine to straighten the chassis.

In australia aren't they 1 year ahead ? So a 94 for them is a 95 for us.

 

Yeah, I believe your correct. So the ECU should be in the passenger footwell.

Just an update.

 

I invited another friend of mine who is also a mechanic, he noticed the connection to the cam sensor was loose and dirty, he played around with it and manage to get the car started.

 

He said that would be the problem. The cam sensor may need to be replaced if the car won't start again in the future.

 

Well, I'm happy that he was able to find the problem. I hope that would be it.