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Discussion Starter #1
I have a 06,na it was running great until last week.
It shut off on my wife wile going to work.
After we towed it him I started looking at it.
It starts fine but after mabey 2 seconds it would shut down.
There's 35-39 lbs or pressure at the fuel rail for 2 seconds then it drops to zero.
With the key to on you could hear the pump for a few seconds then nothing.
The fuses are OK, there's constant power at the pump so I figured it was the fuel pump.
I replaced the pump, and now it won't start at all.
I didn't replace the whole sending unit, just the pump, there was no cracks in the plastic anywhere on the sending unit so figured it was on to reuse.
It's not throwing any codes.
What could be the issue?
I put oem plugs and wires on it a month ago, I took the coil pack off my kids 06 legacy and put it on the outback and it did the same thing start and shut off so it shouldn't be the coil pack.
I'm stumped, it's getting spark, fuel, and air but it won't stay running.

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2009 Subaru Outback
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31 Posts
Is the security light blinking at all? It sounds like it might be an immobilizer issue. I believe these will start and then die quickly if the immobilizer isnt right

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2000 Outback, 2006 Outback XT LTD, 2005 Legacy GT LTD
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40 Posts
Is there any way you got the fuel line connectors crossed? Are they different sizes to prevent that?
 

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Discussion Starter #4
No security lights blinking, I'll go and try swapping the lines around mabey I put the on backward, they are both the exact same connector
 

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Discussion Starter #5
Is there any way you got the fuel line connectors crossed? Are they different sizes to prevent that?
Just double checked the fuel lines, no way to mix them up.
Both are bent molded rubber, one is not long enough to go in the other plug.

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2005 Outback VDC limited 3.0r
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324 Posts
Unplug the maf sensor and see if it runs? Maybe it needs cleaned. Un plugging it will have it run in a default loop.
 

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2008 Subaru Outback Base. 2005 Subaru Outback 2.5i. 2013 Harely-Davidson FLHTK.
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711 Posts
Did you check for a cracked fuel filter cap on the fuel pump module?
 

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Discussion Starter #8
Did you check for a cracked fuel filter cap on the fuel pump module?
Tomorrow morning I'm going to try and start it with the maf unplugged, and retest the pressure at the rail, and if necessary pull out the pump/assembly and look it over.
 

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It starts fine but after mabey 2 seconds it would shut down.
There's 35-39 lbs or pressure at the fuel rail for 2 seconds then it drops to zero.
With the key to on you could hear the pump for a few seconds then nothing.
When the key is turned only to On, (engine is not started), the fuel pump normally runs for 2 seconds and then stops until the key is moved to Start and the engine cranks.

With that 2 seconds, and later with the engine running, the pressure measured at the fuel delivery hose ("T" connection in the fuel line) in the engine area should be 49-52 psi. 35-39 psi is not sufficient to enable the injectors to work properly.

After the key it turned to On and the pump runs for 2 seconds (engine off), what's the pressure, and, does that pressure go down quickly or does it remain steady for some time?

I replaced the pump, and now it won't start at all.
I didn't replace the whole sending unit, just the pump,
Do you still hear the pump run for 2 seconds when the key is turned to ON?
If not, are you sure all the connectors were re-reconnected?

What exactly was replaced? Do you mean the pump electric motor, or the whole assembly minus the fuel level sending unit?

474738


The fuses are OK, there's constant power at the pump so I figured it was the fuel pump.
Constant power, as in always there? Or is it there only under certain conditions/settings, and if so, which? At which pins of the 6-pin connector on top of the pump assembly? (There shouldn't be power to the pump motor all the time)
 

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Discussion Starter #10
When the key is turned only to On, (engine is not started), the fuel pump normally runs for 2 seconds and then stops until the key is moved to Start and the engine cranks.

With that 2 seconds, and later with the engine running, the pressure measured at the fuel delivery hose ("T" connection in the fuel line) in the engine area should be 49-52 psi. 35-39 psi is not sufficient to enable the injectors to work properly.

After the key it turned to On and the pump runs for 2 seconds (engine off), what's the pressure, and, does that pressure go down quickly or does it remain steady for some time?



Do you still hear the pump run for 2 seconds when the key is turned to ON?
If not, are you sure all the connectors were re-reconnected?

What exactly was replaced? Do you mean the pump electric motor, or the whole assembly minus the fuel level sending unit?

View attachment 474738


Constant power, as in always there? Or is it there only under certain conditions/settings, and if so, which? At which pins of the 6-pin connector on top of the pump assembly? (There shouldn't be power to the pump motor all the time)
That plastic housing snaps apart, the fuel pump is in there that's what was replaced.
Yes with the new pump, key on engine not running it still makes the sound for 2 seconds and stops.
 

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Discussion Starter #11
When the key is turned only to On, (engine is not started), the fuel pump normally runs for 2 seconds and then stops until the key is moved to Start and the engine cranks.

With that 2 seconds, and later with the engine running, the pressure measured at the fuel delivery hose ("T" connection in the fuel line) in the engine area should be 49-52 psi. 35-39 psi is not sufficient to enable the injectors to work properly.

After the key it turned to On and the pump runs for 2 seconds (engine off), what's the pressure, and, does that pressure go down quickly or does it remain steady for some time?



Do you still hear the pump run for 2 seconds when the key is turned to ON?
If not, are you sure all the connectors were re-reconnected?

What exactly was replaced? Do you mean the pump electric motor, or the whole assembly minus the fuel level sending unit?

View attachment 474738


Constant power, as in always there? Or is it there only under certain conditions/settings, and if so, which? At which pins of the 6-pin connector on top of the pump assembly? (There shouldn't be power to the pump motor all the time)
power is there wile the key is on, and wile my wife turned the key to start, I forget the voltage exactly but I tested it before tested the pressure.
 

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Power to the 6 pin, I tested it before I pulled the pump
Attached is the wiring diagram showing the connections to the fuel pump. There should be battery voltage at pin 5 of the 6-pin connector (wire color green with yellow stripe) for 2 seconds when the key is turned to On, and when the engine is being cranked or is running.

If the sound of the pump is still heard when the key is turned to On, then that suggests power is getting to the pump motor and that it's running. But that doesn't say anything about the fuel pressure, which earlier was low or flow.

In addition to the pump motor, which has to run at full speed all the time, the pump assembly includes a fuel filter, a pressure regulator, and a venturi pump that draws fuel from the driver side of the fuel tank to the passenger side. The pump motor itself might run, but if the pressure is low because of low voltage, a restriction, or a leak elsewhere in the assembly, the engine might have started but then failed because of insufficient flow, and perhaps now it doesn't start because the fuel delivery is now more deficient or absent.

Not saying that the problem is the fuel supply, but the earlier observations, especially the low pressure, suggest this area should be looked at.
 

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Discussion Starter #14
Tested pressure and it was zero.
Took the pump out again, there was a o ring that wasn't seating correctly.
Put the o ring in right, put the pump and assembly back in.
The car now is back whare it was, it starts for 3 seconds or so and shuts off.
Fuel pressure is 55+ with key on and not running, after start it maintains pressure for the 2 or so seconds its running
 

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Fuel pressure is 55+ with key on and not running, after start it maintains pressure for the 2 or so seconds its running
55+ seems somewhat high relative to the spec, and my own readings. Could be the gauge is off, or the fuel pressure regulator isn't working properly. But unless it's really high, that shouldn't lead to the current symptom. Nevertheless it leads me to ask: What is the actual reading?

Also, what's the current fuel level in the tank?

It maintains the pressure after the engine stops
Okay, I want to be sure I understand this correctly . . .

With the key turned to On (not started), the pressure is 55+ psi. From the On position the key is turned further and the engine is started, and runs for a second or two (as in the video). During that short time the engine is running, does the pressure remain in the 50+ range? And when the engine stops on its own (key is still at On), is it still in the 50+ range?

If the pressure remains in the 50+ range all the time, then it's less likely the problem is fuel (as it certainly was before the o-ring was corrected).

When the engine stops on it's own with the key at On, and the pressure is still good, what happens if the key is turned again from On to the Start position? Does the engine start and then stop again. Or, do you have to first turn the key to Off, and then move back to On and then to Start to restart the engine?

In regard to the above, in post #2 @cam2363 raised the possibility the immobilizer is causing the engine to stop, as the problem now (and was before the pump motor was replaced) is consistent with the descriptions of that system. (See pages 2-3 and 2-4 in Section 2 of your Owners Manual.)

When the key is turned to Off and the key is taken out, does the "Security" light in the instrument panel begin to flash regularly? If not, there could be a problem with the immobilizer system.

If the light does flash, then when the key is put back into the lock, but not turned, does the Security light go out, or does it continue to flash? And does it continue to flash when the key is turned to On, and also after the engine is started?

If the light continues to flash with the key in the lock, then do you have more than one key for the car, and if so, have you tried the other key(s) to see if the engine will continue to run?
 

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Discussion Starter #18
The actual reading is unknown, I'm using a 20 dollar Harbor freight pressure gauge.
Key on no start it primes to around 46,turn the key and start the car it goes over 50,after the stall it drops to mid 40's.
Current fuel level is around half, It was full, I pumped 5.5 gallons out for the fuel pump change.
After the stall if I turn it to start again it starts and runs for about 2 seconds and shuts off.
I'll go down and check the book on the immobilizer, but it does it with both keys.
 

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Discussion Starter #19
55+ seems somewhat high relative to the spec, and my own readings. Could be the gauge is off, or the fuel pressure regulator isn't working properly. But unless it's really high, that shouldn't lead to the current symptom. Nevertheless it leads me to ask: What is the actual reading?

Also, what's the current fuel level in the tank?



Okay, I want to be sure I understand this correctly . . .

With the key turned to On (not started), the pressure is 55+ psi. From the On position the key is turned further and the engine is started, and runs for a second or two (as in the video). During that short time the engine is running, does the pressure remain in the 50+ range? And when the engine stops on its own (key is still at On), is it still in the 50+ range?

If the pressure remains in the 50+ range all the time, then it's less likely the problem is fuel (as it certainly was before the o-ring was corrected).

When the engine stops on it's own with the key at On, and the pressure is still good, what happens if the key is turned again from On to the Start position? Does the engine start and then stop again. Or, do you have to first turn the key to Off, and then move back to On and then to Start to restart the engine?

In regard to the above, in post #2 @cam2363 raised the possibility the immobilizer is causing the engine to stop, as the problem now (and was before the pump motor was replaced) is consistent with the descriptions of that system. (See pages 2-3 and 2-4 in Section 2 of your Owners Manual.)

When the key is turned to Off and the key is taken out, does the "Security" light in the instrument panel begin to flash regularly? If not, there could be a problem with the immobilizer system.

If the light does flash, then when the key is put back into the lock, but not turned, does the Security light go out, or does it continue to flash? And does it continue to flash when the key is turned to On, and also after the engine is started?

If the light continues to flash with the key in the lock, then do you have more than one key for the car, and if so, have you tried the other key(s) to see if the engine will continue to run?
No key in ignition the security light blinks, key in ignition security light stays off, with key on and not starting no security light.
After start and shutdown, turning the key to start will start the car but it shuts back off 2 or 3 seconds later
 
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