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Failing fuel pump symptoms? 96 Legacy


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  • 2 weeks later...
On 4/16/2019 at 3:17 AM, idosubaru said:

Swap the coolant temp sensor next

There are three coolant temp components - one triggers the radiator fans, one is for the dash gauge cluster engine temp, and one is for the ECU.  Swap or replace the one for the ECU. 

 

When it cuts out to you get any symptoms just before or around that time such as: 
A. dash lights lighting up
B. drivability issues, engine getting weak
C. noises

Or it goes from perfect running to not at all instantaneously?

We put in a different MAF for a week and initially it was much better— but then returned to the way it was previously. Then it can be problem free for a day or two. 

Now we finally got a code for the coolant temperature sensor. Where do we find the one connected to the ECU?

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9 minutes ago, Ravenwoods said:

We put in a different MAF for a week and initially it was much better— but then returned to the way it was previously. Then it can be problem free for a day or two. 

Now we finally got a code for the coolant temperature sensor. Where do we find the one connected to the ECU?

 

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19 hours ago, Ravenwoods said:

Now we finally got a code for the coolant temperature sensor. Where do we find the one connected to the ECU?

Coolant crossover pipe. Driver’s side for the RHDrive vehicles, Passenger’s side for the WHDrive vehicles. 

There will be two sensors there. The single wire is the temp gauge on the instrument cluster, the other one that typically has a brown plug and is two wires is for the ECU. That’s the one you want. I need a new one for my EJ22 as well. 

Cheers 

Bennie

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Quote

Now we finally got a code for the coolant temperature sensor

You are very fortunate to get a code.  Of course replace it immediately.

I had very similar symptoms as you have on a 95 and it drove me crazy because I didn't get a code.  After a half dozen stalls, I finally got the MAF code and was then able to solve the problem.  I think this sort of failure is caused by an intermittent short in a solid state device.

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  • 2 weeks later...

We replaced the coolant temperature sensor but there was no improvement. We still don’t have any trouble codes. So I swapped out the following sensors  from a 95 Legacy one at a time with no improvement: Knock sensor, camshaft Position sensor, crankshaft angle sensor.

Now I’m planning on swapping the fuel pump too. Any other suggestions?

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4 minutes ago, el_freddo said:

Did you flash the ecu between each sensor being swapped? 

Is the cam timing lining up as it should?? 

Cheers 

Bennie

No. How do you flash the ECU?

How do you check the timing? I looked at live data with the OBD2 code reader and It says Ignition Advance is 14 degrees when the engine is warm and idling in contrast to the other Legacies which read 20 degrees.

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2 minutes ago, Ravenwoods said:

No. How do you flash the ECU?

How do you check the timing? I looked at live data with the OBD2 code reader and It says Ignition Advance is 14 degrees when the engine is warm and idling in contrast to the other Legacies which read 20 degrees.

There’s a set of connectors to erase stored codes, but I’m unsure about the exact details. Instead I do the “battery dance” - disconnect the battery for a few minutes. Half hour to be really sure! 

Start the engine but do not touch the throttle. Idle may waiver up and down a little, this is normal. Don’t touch the throttle or put it in gear until the fans have cycled at least once, I usually do twice. 

Then you can go for a drive or shut it down and have lunch etc. 

By checking timing I’m taking about the cam belt timing. Sorry I should’ve been more explicit about that. Just check to see that it’s all aligned as it should be. 

Cheers 

Bennie

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16 minutes ago, el_freddo said:

There’s a set of connectors to erase stored codes, but I’m unsure about the exact details. Instead I do the “battery dance” - disconnect the battery for a few minutes. Half hour to be really sure! 

Start the engine but do not touch the throttle. Idle may waiver up and down a little, this is normal. Don’t touch the throttle or put it in gear until the fans have cycled at least once, I usually do twice. 

Then you can go for a drive or shut it down and have lunch etc. 

By checking timing I’m taking about the cam belt timing. Sorry I should’ve been more explicit about that. Just check to see that it’s all aligned as it should be. 

Cheers 

Bennie

So we want to check the timing belt to make sure the lines and marks are all aligned correctly?

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3 hours ago, Ravenwoods said:

So we want to check the timing belt to make sure the lines and marks are all aligned correctly?

since it's intermittent i think you're guaranteed to find them lined up.  what might be off is the tensioner - but if it's intermittent it's going to look fine when you look in there.   

if you do go in there look at the tensioner that's the only part that could be failing intermittently - see if the hydraulic pin is wet or deformed in any way.  

i've seen loose EJ tensioners (new style) and the drivers side belt will slop around while driving.  you could leave the drivers side timing cover off (it's only 3 10mm botls and takes a couple minutes to remove, very easy) and try to look at it when the car has symptoms. 

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4 hours ago, Ravenwoods said:

No. How do you flash the ECU?

you don't, not sure what they have in his country, but that is not an appropriate course of action for any 1990's US market Subaru. 

swap sensors and carry on just like you did.  the ECU has no idea what sensor is in there, there's no identifying data for a specific sensor. 

you can swap ECU's (which thereby changes *all* the sensors) - plug in another ECU and drive immediately.  which, since you have additional vehicles and an untraceable issue you could try.  plug in another ECU and see what happens.   model and EJ22 or EJ25 doesn't matter as long as they're all 1995-1998 legacy/outbacks/foresters - all the ECU's are plug and play interchangeable. 

Edited by idosubaru
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5 hours ago, idosubaru said:

you don't, not sure what they have in his country, but that is not an appropriate course of action for any 1990's US market Subaru. . 

Sorry, I meant flash as in remove stored codes. No good changing sensors, check codes and still have the same stored codes showing up. You’ll be chasing your tail if you’re not clearing these! 

May least that’s how I operate in my shed, it works for me every time. 

Cheers 

Bennie

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10 hours ago, el_freddo said:

Sorry, I meant flash as in remove stored codes.

Sure, most on here are familiar with reading and clearing codes. "flash" is confusing as it implies tuning.  google subaru flash ECU and it'll show COBB, tactrix, open source...us old school owners know the real 'flashing' ECU's - counting LED's to get our codes, haha. 

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2 hours ago, idosubaru said:

us old school owners know the real 'flashing' ECU's - counting LED's to get our codes, haha. 

Yeah we do! 

(OBD1 EJ22 in my L series) 

I’m now about to replace the CTS, and I’ve just replaced the O2 sensor since this film was made. 

Cheers 

Bennie

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On 5/10/2019 at 11:00 AM, idosubaru said:

you don't, not sure what they have in his country, but that is not an appropriate course of action for any 1990's US market Subaru. 

swap sensors and carry on just like you did.  the ECU has no idea what sensor is in there, there's no identifying data for a specific sensor. 

you can swap ECU's (which thereby changes *all* the sensors) - plug in another ECU and drive immediately.  which, since you have additional vehicles and an untraceable issue you could try.  plug in another ECU and see what happens.   model and EJ22 or EJ25 doesn't matter as long as they're all 1995-1998 legacy/outbacks/foresters - all the ECU's are plug and play interchangeable. 

I finally had a chance to swap the ECU from a 95 Legacy into the 96 Legacy. Our problem car, the 96 now doesn’t start at all. The 96 had the 8D ECU. The 95 has the 2D ECU.

image.jpg

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On 5/11/2019 at 5:23 AM, el_freddo said:

Yeah we do! 

(OBD1 EJ22 in my L series) 

I’m now about to replace the CTS, and I’ve just replaced the O2 sensor since this film was made. 

Cheers 

Bennie

Our 96 Legacy starts well, not at all like this video.

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On 5/10/2019 at 10:54 AM, idosubaru said:

since it's intermittent i think you're guaranteed to find them lined up.  what might be off is the tensioner - but if it's intermittent it's going to look fine when you look in there.   

if you do go in there look at the tensioner that's the only part that could be failing intermittently - see if the hydraulic pin is wet or deformed in any way.  

i've seen loose EJ tensioners (new style) and the drivers side belt will slop around while driving.  you could leave the drivers side timing cover off (it's only 3 10mm botls and takes a couple minutes to remove, very easy) and try to look at it when the car has symptoms. 

I replaced the belt and tensioner today with no improvement. I had already swapped out the MAF with a 95 AT Legacy which did not seem to help. So today I took a different MAF from a different 95 AT Legacy and neither car has any bad behaviors with the swapped MAF sensors. All the MAF Sensors have different numbers on them. Very strange how the problem suddenly disappears from time to time.

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when mine died the car started and drove 10 feet then cut out and stalled would not start again until i banged on the top of the pump unit a few times then it started again ran another 5 or 10 seconds and died again. no matter what happened it wouldent stay running unless i was tapping on the top of the pump unit with a long bar from the front seat.

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Sounds like an intermittent electrical connection. Being in Alaska I would put my money on corrosion somewhere. Start wiggling wiring connections and harnesses with the engine running and see if you can replicate the issue. Sounds like it's related to the drivetrain shifting when driving at lower speeds and accelerating from a stop, etc since you say it rarely, if ever, does it on the highway. 

Another potential is a dead spot in the TPS. Check it with a scope if you can. 

Don't troubleshoot with the parts cannon. 

GD

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