05 2.5I, MT.
Recently starting getting inability to rev past 4K.
No stumbling or anything else until I get just past 4k.
Occurs in any gear.
Have access to an Autel scanner, but so far can't pin it down.
Does not seem like fuel starvation, but what do I know?
Nor like a partially clogged cat.
Unplug the TPS at TB ( DBW). After a few minutes of learning, it revs to redline, but after 5 minutes or less of actual driving, it starts again.
No codes, so am at a loss.
Suggestions?
O.

Update:

Am finding that the short term fuel trim on Bank 2 is off.

Running lean, Numbers in the negative.

Had a spare and replaced the upstream O2. No change.

Will swap the downstream from one bank to the other and see if the bad trim follows.

BTW this is the late 04 and early 05 which has 5 O2 sensors and the modified H6 exhaust to fit the 2.5.

Will advise.

Still looking for suggestions.

negative Trim numbers mean the ECU is pulling fuel so, rich-condition is what you probably need to look for. On some cars, the fuel pressure regulator leaks fuel down its vacuum hose causing rich running.

 

If you had slipped timing on one bank's cam pulley, maybe that would also show up as neg fuel trim? Probably limit revving too. But that would not be fixed by unplugging a sensor or resetting the ECU.

 

any other codes? Does that engine have AVLS, maybe a problem with that?

Edited April 10, 20214 yr by 1 Lucky Texan

Only code is an evap one. Not related obviously.

Didn't get chance to swap o2's. If friends garage is open tomorrow, will get a chance. Will check timing.

Non AVLS.

Will advise.

O.

find the FPR and look for wetness in it's vacuum line.

No wetness, but there is a gas smell in the compartment. Which quickly dissipates

On the 05 CA model there is an FPR (modulator) on all three fuel lines.

Notice from a cold start on medium throttle, I get pulsing, for a small time, until the car warms up

Have access to FPR's at local yard from an 05 and will look into replacing 2 of them.

Will advise.

 

Update.

Thank you to Lucky Texan, it was indeed in the vent line.

There was a crack in the hose at the barb fitting. Cut it out and all is good.

Thanks again.

Who wouda thunk it?

so, it was a vacuum leak at the FPR - or was there also fuel?

 

anyway, not sure I was right, but glad it led to finding the problem!

No fuel.

Not at the fpr itself but on the line that connects to the metal end of the intake.

 

Update!!!!!!

Earlier fixes were just coincidental, Issue returned and after more research, the car was going into limp mode and the fuel was being cut.

Could not figure it out.

Recently had an unusual flat where the tire had to be replaced. Bought a new set as they were at the end of their life anyway.

Two of the rims were so out of round that they could not be balanced.

Finally got two new rims of same style and switched the tires.

Issue solved!!!!

It seems the wheel sensors told the ecu that things were off and put into limp mode.

In other words balance the tires.

Hope this helps the next person.

Edited June 10, 20214 yr by ocei77
add

Just an FYI on those ULEV engines - the catalytic converters for those cars are now $10,000 from Subaru. So make SURE it doesn't ever misfire and damage them.

GD

$10,000 hahaha - I’ll pass on that. 

Fuel being cut due to a bent rim, wow.  What position were the bent wheels in - both front, both rear, or one front and one rear?

didn’t know that was possible, forgive me for being inquisitive.

How do you know this isn’t like previous times when a fix was coincidental and the issue returned?

It seems odd for a bent wheel to cause limping and fuel trim issues.

my 2009 has a bent wheel that can’t be balanced. No CEL and engine runs fine.  have had bent wheels before though I don’t recall which model/years...

So if I temporarily hang some weights on one or two of my wheels....?
 

I think I’ll hold onto my L series and brumby for as long as I can!! 

$10G for an exhaust part is ridiculous to say the least!

Cheers 

Bennie

for 10k i would go buy a different car.. that is just nuts

 

Don't know which axle they were on. Just that the installer could not get them to balance they were so out of round.

Placed both on rear until I changed them.

Seems like wheel sensors threw an ABS code as it couldn't figure out what was what.

The ABS fault after a time put it into limp mode.

See DTC 0500 for vehicle speed sensor

O.