02 WRX 4.5krpm hesitation

[Meester Idunno]

I have an '02 WRX wagon with 41-something thousand miles on it. It's
always been US dealer maintained, and while I sometimes (often?) drive
in a spirited manner, the car has never been abused or raced.

At or near full throttle, while accelerating through 4000 to 5000 rpm,
the engine feels like it's suddenly making 50 fewer hp. Below and above
feel fine. Before I make another service appointment (it was there only
a couple of weeks ago), is there anyone out there that has any ideas of
things I could check on my own?

Today it seemed much less pronounced, but still there - making me think
it could be something as a bad tank of gas. But the fact it only
happens in a very narrow rev range makes me suspicious. It started at
or shortly after the last dealer visit, when they replaced the gears,
synchros, and hub for 3rd and 4th gears. Now my shifter doesn't feel
'right' going into 3rd gear half of the time, but it works. It felt
perfect before the tranny work. I wonder if it-just-doesn't-feel-right
issues are covered under the powertrain or extended warranty docs.

This is my first newsgroup posting of any kind, even though I've been
emailing since 1992. I'm using a throwaway email address for NGs...

Byron

 

[Ken Gilbert]

I have an '02 WRX wagon with 41-something thousand miles on it. It's
always been US dealer maintained, and while I sometimes (often?) drive
in a spirited manner, the car has never been abused or raced.

At or near full throttle, while accelerating through 4000 to 5000 rpm,
the engine feels like it's suddenly making 50 fewer hp. Below and above
feel fine. Before I make another service appointment (it was there only
a couple of weeks ago), is there anyone out there that has any ideas of
things I could check on my own?

Today it seemed much less pronounced, but still there - making me think
it could be something as a bad tank of gas. But the fact it only
happens in a very narrow rev range makes me suspicious. It started at
or shortly after the last dealer visit, when they replaced the gears,
synchros, and hub for 3rd and 4th gears. Now my shifter doesn't feel
'right' going into 3rd gear half of the time, but it works. It felt
perfect before the tranny work. I wonder if it-just-doesn't-feel-right
issues are covered under the powertrain or extended warranty docs.

This is my first newsgroup posting of any kind, even though I've been
emailing since 1992. I'm using a throwaway email address for NGs...

Byron

byron,

fill the tank with the highest octane gas you can find, then reset the
ecu. do this by disconnecting battery terminal for a minute, with
some draw on the battery (ie, have interior dome lights turned on).
then, get back in the car, and drive fairly spiritedly.

if the hesistation comes back, it's a cause for more concern.
otherwise attribute it to a bad tank of gas, with insufficient octane,
which causes knock, which the ecu picks up on, and correspondingly
reduces ignition advance and lower power. the ecu has many different
"load cells" which cause the hiccup to be very localized along the
powerband.

hth
ken

 

[zippy]

I (and many others with '02 WRXes) have had this problem. If you have what we've had, it's bad electrical grounding. You'll find that Subaru inexplicably attached its grounding wires over painted metal -- not the best recipe for a good connection. The good news is that it's an easy problem to fix. Just undo the connections, sand off the paint, apply dielectric grease, redo connections and resume driving.

Good luck...

 

[Verbs Under My Gel]

I have an '02 WRX wagon with 41-something thousand miles on it. It's
always been US dealer maintained, and while I sometimes (often?) drive
in a spirited manner, the car has never been abused or raced.

At or near full throttle, while accelerating through 4000 to 5000 rpm,
the engine feels like it's suddenly making 50 fewer hp. Below and above
feel fine. Before I make another service appointment (it was there only
a couple of weeks ago), is there anyone out there that has any ideas of
things I could check on my own?

Today it seemed much less pronounced, but still there - making me think
it could be something as a bad tank of gas. But the fact it only
happens in a very narrow rev range makes me suspicious. It started at
or shortly after the last dealer visit, when they replaced the gears,
synchros, and hub for 3rd and 4th gears. Now my shifter doesn't feel
'right' going into 3rd gear half of the time, but it works. It felt
perfect before the tranny work. I wonder if it-just-doesn't-feel-right
issues are covered under the powertrain or extended warranty docs.

This is my first newsgroup posting of any kind, even though I've been
emailing since 1992. I'm using a throwaway email address for NGs...

Byron

What happened to third and fourth gears?

 

[Meester Idunno]

What happened to third and fourth gears?

I'm not quite sure - and I was a bit shocked that they had to replace
all that stuff. I brought it in because it was occasionally grinding
when I tried to shift into 4th. 1st and reverse were (and still are) a
bit cranky, but they are not grinding. I would have to move the shifter
back into neutral for a second or three before I tried a 2nd time, which
always worked. Beforehand I did little things on my own like moving the
seat up further to make sure the clutch was being pressed all the way
in. It was. The dealer told me to bring it back in a few weeks - they
ended up keeping it for 3 days, during which (among other wear items I
had them fix) they replaced gears, synchros, and hub for 3rd and 4th.
The problem seemed to be getting worse over the last couple of months.
Still, it only happened one time in about 10. I do mostly city driving
these days, so 4th gear use was a lot higher than with any other car
I've used. I never noticed any problem with 3rd - I guess they saw
something when the tranny was opened up. The 4th gear grind could
happen under fast acceleration or during relaxed driving when I was
shifting from 2nd directly to 4th or anywhere in between - it didn't
matter.

The dealer was quite nice about things, and covered the tranny work
under warranty, but they said they had to send the parts back to SoA to
verify they weren't abused. I wish I had thought to ask to see them so
I could see for myself what happened.


I'm not quite sure what a hub does - can someone enlighten me?

Byron

 

[Byron Raymond]

I (and many others with '02 WRXes) have had this problem. If you have what we've had, it's bad electrical grounding. You'll find that Subaru inexplicably attached its grounding wires over painted metal -- not the best recipe for a good connection. The good news is that it's an easy problem to fix. Just undo the connections, sand off the paint, apply dielectric grease, redo connections and resume driving.

Good luck...

Geez - the people who installed my stereo 9 months ago made sure to
prepare the ground from the amps in the way you describe... but then
again taking care of the little details like that is the reason I chose
them in the first place. I wonder why Subaru did something silly like
this. Where in the engine compartment is it? I assume you're talking
about the wire going from the battery to what usually is a frame or body
member?

I'll also try resetting the ECU with Ken's suggestion. Thanks to both
of you. I'll try both things and report findings when I know something
definitive.

_
Byron

 

[Meester Idunno]

I (and many others with '02 WRXes) have had this problem. If you have what we've had, it's bad electrical grounding. You'll find that Subaru inexplicably attached its grounding wires over painted metal -- not the best recipe for a good connection. The good news is that it's an easy problem to fix. Just undo the connections, sand off the paint, apply dielectric grease, redo connections and resume driving.

Good luck...

Geez - the people who installed my stereo 9 months ago made sure to
prepare the ground from the amps in the way you describe... but then
again taking care of the little details like that is the reason I chose
them in the first place. I wonder why Subaru did something silly like
this. Where in the engine compartment is it? I assume you're talking
about the wire going from the battery to what usually is a frame or body
member?

I'll also try resetting the ECU with Ken's suggestion. Thanks to both
of you. I'll try both things and report findings when I know something
definitive.

-
Byron

 

[zippy]

I know what you mean. I was astounded it could happen. There are three connections. One is near the battery and attaches on the frame near the air cleaner. There's another one on the other side of the engine compartment, pretty much opposite that one. And there another behind the intercooler. I couldn't reach that one, so I left it alone, and the problem went away anyway.

 

[Meester Idunno]

I did as you said below. It worked perfectly - my WRX is back! I
disconnected the battery, while I worked, so I assume the ECU was reset
at the same time. I found that the connection near the battery seemed
to have metal-to-metal contact, but the one near the airbox not only was
painted over, but in my car a big glob of paint that probably prevented
the star washer from fitting flush. Getting the paint off was not
difficult, but getting the primer off required a metal grinding wheel
for my Dremel tool.

Many thanks!
-Byron

 

[Meester Idunno]

I really should check my grammar before sending messages... Yikes!

 

[zippy]

Excellent! I'm glad it worked.