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Old 03-06-2013, 08:30 PM   #1
ninefourteener
Scooby Newbie
 
Member#: 104414
Join Date: Jan 2006
Chapter/Region: RMIC
Location: SLCSUBARU.COM-Co-founder/Admin
Vehicle:
SUBY 06WRX 07TRIBECA
78BRAT 94SVX-LSi

Default 06 WRX fuel pressure issue - FRUSTRATED

I'm so frustrated because I have found 15 different threads with similar issues.... and they all end with someone saying "I have the same problem, did you ever figure out what the problem is?"

06 wrx. Vf39. Fully catless 3" tbe, Cobb ots map - been using it for 6 years. spt intake, sti I/c, walbro 255 and oem subaru filter have less than 20k miles on them

Im the only owner.... 74k miles on car. No one has ever touched it but me.... and it has been meticulously serviced always.

Car runs (or appears to) fine most of the time.
Intermittent slight hesitation between 2800-3800 rpm
No cel
Still using accessport v1... never saw a reason to upgrade.... cannot datalog
Fuel pressure gauge CONSISTENTLY reads about 10 psi lower than it should.
Ignition on-40 psi of fuel press for 2 seconds... then zero
Start car w/no problem.... idles at 24psi, about 12-15 vacuum
Full boost (18psi)... fuel pressure is at 50psi
Those numbers "should" say 34 and 60 (ish) respectively
Maf is clean
Filter is clean
No fuel leaks anywhere..... strong fuel smell in exhaust
Did the fuel pressure regulator test- pulled the vacuum line off- fp jumped to 34 exactly as it is supposed to..... but AGAIN, about 10 less than it should be.

This is SO frustrating.... because ive been running this setup for 6 years.... and have never even thrown a cel. And I'm still not..... so I cant even look up a code to start troubleshooting.

I greatly appreciate your help..... hopefully someone recognizes the "gremlin" and can help me out
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Old 03-06-2013, 08:40 PM   #2
ninefourteener
Scooby Newbie
 
Member#: 104414
Join Date: Jan 2006
Chapter/Region: RMIC
Location: SLCSUBARU.COM-Co-founder/Admin
Vehicle:
SUBY 06WRX 07TRIBECA
78BRAT 94SVX-LSi

Default

Added- no leaks around injectors
No fuel smell under the hood
Fuel pressure is appropriate (40psi) with ignition on.
Low fuel pressure only exists when engine is running...... and appears to be consistently about 10psi lower than it should be throughout the entire powerband.
The slight hesitation/bucking is not only intermittent.... is is moderate enough to avoid throwing a cel.

I have "considered" installing an adjustable fpr and manually increasing the fp..... but this doesnt address the underlying problem.

Help!
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Old 03-06-2013, 10:44 PM   #3
ninefourteener
Scooby Newbie
 
Member#: 104414
Join Date: Jan 2006
Chapter/Region: RMIC
Location: SLCSUBARU.COM-Co-founder/Admin
Vehicle:
SUBY 06WRX 07TRIBECA
78BRAT 94SVX-LSi

Default

I just realized something..... when I turn the ignition on..... my fp primes at 40 psi for 2 seconds...... and then drops to zero.

I dont think it is supposed to do that. Could this be my problem?

There has to be some sort of 1 way check valve or something in the system that is supposed to hold pressure...... that is either broken.... or missing.

Anyone have any insight?
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Old 03-07-2013, 02:58 PM   #4
mechatricity
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Member#: 290592
Join Date: Aug 2011
Chapter/Region: South East
Location: Charlotte, NC
Vehicle:
04 & 06 WRX Wagons
'15 WRX 6MT CWP

Default

I have the same problem, did you ever figure out what the problem is?

Just kidding. This might sound crazy, but how old is your battery?
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Old 03-07-2013, 08:38 PM   #5
Uncle Scotty
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Member#: 16200
Join Date: Mar 2002
Vehicle:
OK Houston
we have an Uncle

Default

bad fpr...they DO go bad....or the vac hose to it is bad or something like that
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