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Wes Harden

Wes Harden

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2011 Forester X, 2.5l, fb25 non turbo, awd

This car is setting a P0171, lean code.
Today I smoke checked the intake, found a leak at the pcv. A pretty good leak, bingo got it.

Take it for a test drive runs better. Stalled coming to a stop 2x. The more it was driven the better it ran. Pull into shop shut it off. Try yo restart, cranks but light off. It wants to but just quite won't. Wait 5 minutes and it starts.

Sets code P0171 after restarting. Scan tool shows front o2 1.0v at idle,virtually no change in voltage. Maf shows 23-25 lb/h. inj pulse width 3.3-3.5 ms at idle, 2.5 ms at @ 2k. It is runing rich. I can smell it running rich.

In the last few months a lit of work has been done.
Cooling system leaks repaired,
New rad, 1 fan, hoses,o rings on cross over. Computer showing 203° F on scan tool.
Intake plenum new seals, throttle body cleaned and new seal, egr inlet tube new seals.
Egr valve new,( genuine Subaru)
Rebuilt injectors, fuel pump replaced. Pwm system.
Have inspected for upstream exhaust leaks nada. Re smoked the intake nada.
Vacuum guage shows a nice 17.7 in needle vibrates slighty at idle. Rev to 2k 21in ans steady needle.

I know i am leaving out other stuff i checked.
I am missing something here,
Need one of you to go did ya check .....
 
Wes Harden said:
2011 Forester X, 2.5l, fb25 non turbo, awd

This car is setting a P0171, lean code.
Today I smoke checked the intake, found a leak at the pcv. A pretty good leak, bingo got it.

Take it for a test drive runs better. Stalled coming to a stop 2x. The more it was driven the better it ran. Pull into shop shut it off. Try yo restart, cranks but light off. It wants to but just quite won't. Wait 5 minutes and it starts.

Sets code P0171 after restarting. Scan tool shows front o2 1.0v at idle,virtually no change in voltage. Maf shows 23-25 lb/h. inj pulse width 3.3-3.5 ms at idle, 2.5 ms at @ 2k. It is runing rich. I can smell it running rich.

In the last few months a lit of work has been done.
Cooling system leaks repaired,
New rad, 1 fan, hoses,o rings on cross over. Computer showing 203° F on scan tool.
Intake plenum new seals, throttle body cleaned and new seal, egr inlet tube new seals.
Egr valve new,( genuine Subaru)
Rebuilt injectors, fuel pump replaced. Pwm system.
Have inspected for upstream exhaust leaks nada. Re smoke.
Vacuum guarates slighty at idle. Rev to 2k 21in ans steady needle.

I know i am leaving out other stuff i checked.
I am missing something here,
Need one of you to go did ya check .....
Click to expand...
Head gaskets… ?


Just throwing it out there cause I hear they are bad for that, no real experience with them.
 
I think that was the EJ25. Every 60k.
These FB25 engines do have oil consumption problems. Subaru replaced a ton of long blocks and list a class action suit behind this.
I have done a compression test and leak down. Cylinders were even and i never had air leaking out of adjacent cylinder or massive amounts from crank case. Compression wasn't as high as i would have liked.
 
Unrelated , but our good friends daughters car , I think it’s a 2012 Fb20 had a big hole in the block right up top under the alternator.

I had a pic but deleted it.

Shame… super nice car in great shape.
 
Maf inspected and ckeaned no change on pounds per hour.
O2 is possible it reads a steady 1.0v
I have never seen them fail like that. Normally when the cross counts drop they get changed. This one never changes
 
Wes Harden said:
Maf inspected and ckeaned no change on pounds per hour.
O2 is possible it reads a steady 1.0v
I have never seen them fail like that. Normally when the cross counts drop they get changed. This one never changes
Click to expand...
Oh yeah I’ve seen that. Start there
 
O2 reading is suspicious. Prob want to doublecheck the wiring also.

Is the rear O2 making any changes? I know they're flatter usually, but is it reading 'normal' ish?
 
So sounds like that one is working, and measuring change. So yeah, front o2 needs some examination. Any possibility that this thing had some tune that could cause it to ignore the front o2?
 
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