Flaring

What does it mean when the engine "flares on upshift?" Not being a
native English speaker, I never heard the verb "flare" used in this
context, so I'm not sure what symptom it is. Can anybody describe it in
another way?

Thanks,
Rudy

 

That's when the revs momentarily increase instead of dropping when you lift
off the gas pedal, a very annoying artifact of emissions controls. It used
to be much worse in the days of carburetors.

You can get rid of it by disconnecting the IAC/EACV, but then you get way
too many undesired side-effects. Flare-ups are here to stay.

I find my '91 Integra does that at certain ambient temperatures if I shift
under 4,000 rpm.

 

in automatics, it means that the revs momentarily rise way above their
last rpm's before the next gear locks in. it's a transmission problem
commonly associated with using the wrong transmission fluid.

 

Thanks. I think this is what was meant in that reference because it
was in AT context. Would such a flare up be also accompanied with a
kinda' howling noise?

Rudy

 

sure.

 

Hmmm ... But I have changed the ATF twice with Honda ATF-Z1, so it
should not be due to wrong ATF. Well, I might know more at this time
tomorrow.

Rudy

 

ok, tell us the age, model, mileage, etc. and let's see if we can be
more specific. my civic used to flare on downshifting for hills. i
cured it when i addressed another [seemingly unrelated] issue the car had.

 

'94 Accord LX, 205 K miles. During acceleration it seems to slightly
flare up with that howling sound when the AT is switching gears and also
when I lift my foot off the accelerator slightly, so there is a slight
engine brake condition. This is especially pronounced when the engine
is still cold.

Rudy

 

a recent thread identified a torque converter issue with hondas this
vintage, but i can't confirm because i've not experienced this myself.

 

That thread was also started by me and you could read the conclusion of
it that I just posted there. As it turned out, it wasn't the torque
converter at all, but the AC compressor.

Rudy

 

good - from the converter viewpoint. can't say i understood /how/ it
could be a problem like you described. lockup clutch is one thing, but
for driveaway, the converter has no wearing parts. the casing or the
internal vanes can fatigue, or the mounting plate can fatigue, but that
all would be way more obvious than the symptoms you described.

regarding the a/c compressor, shouldn't be causing flaring. you've done
the atf a couple of times. should wait a couple of weeks between each
change. and maybe try a 3rd. the 3rd one on mine made a difference.

the other thing i found was making sure the engine tuning was dead-on.
i had multiple little issues that meant the engine wasn't quite right.
the timing was slightly off, the timing belt was too loose so the cam
timing was eratic, and i cleaned up the egr valve. new thermostat
helped too. little things!

 

That torque converter idea was not mine but of a long time Honda service
technician who made that diagnosis as soon as he turned on the ignition
key on a test drive. I'm sure glad I got a second opinion an that!

Well now that the problem turned out not to be related to the AT, that's
a moot point.

Yes indeed, this independent also adjusted the engine timing and that
also makes quite a difference. For one, I don't get pinging and the
engine also seems to run cooler, judging from the decreased frequency my
radiator fan kicks in after I turn off the engine. It used to do it
almost every time I got home, even on not-so-hot days.

Luckily, both my thermostat and EGR valve was replaced only about 5 K
miles ago, so my car runs pretty smooth now.

Rudy