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2014 Forester CVT
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4 Posts
Discussion Starter #1
Hello!

Changed the spark plugs in the 2014 Forester the other day and now I've got a problem where the car will start up just fine when cold but starting up the thing when the engine is warm will produce an immediate stall.

It essentially seems like the normal turnover process happens and then once it comes back down to idle it dies. The whole process is very quick.

Interestingly, if we move the key to the "on" position for a good 3-4 seconds and THEN turn to start the car, no issues at all. Only when you move the key straight through to start/turn over the motor does it then die, and only when warm.

To change the spark plugs I did have to unplug the MAF and remove the battery. As a trouble shooting step when this first started happening I unplugged the MAF and then started the car and it started right away, while throwing the SES light. Not sure if this indicates the sensor is going bad or the higher idle demanded by the ECU due to lack of MAF signal keeps the car running.

Is this the sign of a failing MAF? No codes are being thrown.
 

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Administrator
2007 Forester Sports XT 4EAT
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38,953 Posts
@anasazi some members have had to use this procedure, after the battery was disconnected.
Bobby...

['07 FSXT Member Journal] ['03 X Member Journal]
 

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non-subaru
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911 Posts
Interestingly, if we move the key to the "on" position for a good 3-4 seconds and THEN turn to start the car, no issues at all. Only when you move the key straight through to start/turn over the motor does it then die, and only when warm.
I wonder whether this isn't some sort of fuel problem, maybe an injector that's leaking:
When you turn the key not all the way the way you describe, it pressurizes the fuel system.
Maybe the fuel isn't quite up to the right pressure wen you turn all the way through in one sho because one leaking injector is depressurizing the system

I'd run some Techron through the system. It is cheap and cleans the injectors.
 

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2012 Forester 4 speed auto
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1,055 Posts
Your MAF sensor also has a Intake Air Temperature sensor. When you disconnected the MAF sensor it defaulted to the throttle positioning sensor and the car started. I would qualify the MAF to see if it is defective or if you feel lucky just replace it.
 

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2014 Forester CVT
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4 Posts
Discussion Starter #5
As a follow up --

Tried the idle re-learn procedure with limited results. Might have improved the situation a bit, but certainly didn't fix it.

Didn't try anything else, gradually the issue went away. It took awhile, though. Occasionally when coming to a stop and the a/c compressor kicked on it'd stumble a bit, but even that has gone away. If I had to venture to guess, the MAF is probably outside of spec and the computer has had to re-learn how to compensate for it.

I suspect the next battery change I'll run into the same issue again.

This Forester has been a POS since about 20k miles, and we're only at 70k now. Crossing fingers that it lasts to 100k at least...
 

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MY13 2.5i-S CVT FB25
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45 Posts
As a follow up --

Tried the idle re-learn procedure with limited results. Might have improved the situation a bit, but certainly didn't fix it.

Didn't try anything else, gradually the issue went away. It took awhile, though. Occasionally when coming to a stop and the a/c compressor kicked on it'd stumble a bit, but even that has gone away. If I had to venture to guess, the MAF is probably outside of spec and the computer has had to re-learn how to compensate for it.

I suspect the next battery change I'll run into the same issue again.

This Forester has been a POS since about 20k miles, and we're only at 70k now. Crossing fingers that it lasts to 100k at least...
Hi, has it happened again since? I would like to know the permanent solution to this. A few things people have suggested are:
  • Possible evap leak (i dont know what evap means at the moment)
  • MAF sensor clean / replace (seems easy)
  • fuel pump relay replace (no idea what this involves)
  • ignition coils (as above)
  • reset ecu (easy)

My Forester 2.5 liter has been stalling infrequently over the past few months. It's no big deal as i have an easy workaround (blip the throttle immediately after start up). I have posted a video of it on youtube:
 

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2014 Forester CVT
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4 Posts
Discussion Starter #7
Hi, has it happened again since? I would like to know the permanent solution to this. A few things people have suggested are:
  • Possible evap leak (i dont know what evap means at the moment)
  • MAF sensor clean / replace (seems easy)
  • fuel pump relay replace (no idea what this involves)
  • ignition coils (as above)
  • reset ecu (easy)
My Forester 2.5 liter has been stalling infrequently over the past few months. It's no big deal as i have an easy workaround (blip the throttle immediately after start up). I have posted a video of it on youtube:
Nope, it gradually went away to where its basically normal. I'm just about a year out and no issues have come back.

It'll suck at next battery change though as I expect the problem to return.

I suspect the MAF, but no way to know without proper test equipment (don't have) or swapping with a known good part and seeing if the problem follows.
 
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