drop in gas mileage and gauge problems

[thomashanno]

1997 subaru outback with 142000 miles...head gasket blew about 200
miles ago, fixed by the dealer. about 4 days ago i filled up and my
gas gauge started dropping pretty quickly. i've ruled out a leak (had
one last year) because i haven't smelled any gas after i park or seen
any puddles. sometimes i think i smell gas in my exhaust though. my
gauge was showing that i was getting about 4 mpg, but when I refilled
it was off and i was actually getting 13 mpg (as opposed to my normal
20-25). any idea what could be causing this?


thanks,
thomas

 

[strchild]

Anybody think a compression test might be in order, to see if the valves are
seating properly, or what are the chances the timing is off a tick, since
the head gasket(s) were just done? I'm really unsure the possibility of
running the motor with the timing off a tick though, as it's interference.
I was told that Subaru's aluminum heads needed to be checked extremely well
for flatness when doing gaskets, and sometimes baked and straightened from
warpage before flattening, or the problem has a high likelyhood of repeating
itself, and it may even be necessary to do valve guides?

Don't yell at me guys, just suggesting. I would think a compression test
far better than burning a valve, if anybody even thinks it could be that, or
maybe it's just running rich?

~Brian

 

[bgd]

for the given liters 13mpg is an extreme, but doable with the intake
manifold bigger than the biggest big block gasoline engine america has ever
made. Beyond the smell of fuel would be happening in the exhaust if it was
engine. I had a very old subaru (ya know those 13 year old ones with a real
boxer?) that went to 18mpg , I though that was impossible, but fuel
injection can do that. Action for a reaction is All fuel injection systems,
so fuel out the exhaust is very likely if it is flooding with slow misguided
sloppiness for the gigantic intake to pretend with. timing is a great guess.
timing of something isn't right.(An old carb would just simply flood with
similar problems)
That is ashame about the headgasket. It is well into the dozens of
different threads about that very mishap for they year or so I have been
checking this group and other places. WAY Too common.
As far as the head conforming... Those 2 cylinder heads would conform to a
damn egg. Yet another genioused benefit of a boxer. Subaru and the children
in the engineering department destroyed it (along with that ridiculous
crankshaft).
Happy Day.

I hope the "big daddy" of Subaru kicks the kids out soon. I am getting too
old to stay patient even with other's Subaru problems....more than ironinc
all new ones.

RIDICULOUS.Its blashemy, its gangstas in charge, its highway robbery, its
the mob, its suicide (I could babble forever!)

Good Luck on your fuel problem~ it seems trivial when you can't even have
correct engineering in and on the engine.

 

[Porgy Tirebiter]

Anybody think a compression test might be in order, to see if the valves
are seating properly, or what are the chances the timing is off a tick,
since the head gasket(s) were just done? I'm really unsure the
possibility of running the motor with the timing off a tick though, as
it's interference. I was told that Subaru's aluminum heads needed to be
checked extremely well for flatness when doing gaskets, and sometimes
baked and straightened from warpage before flattening, or the problem has
a high likelyhood of repeating itself, and it may even be necessary to do
valve guides?

Don't yell at me guys, just suggesting. I would think a compression test
far better than burning a valve, if anybody even thinks it could be that,
or maybe it's just running rich?

~Brian

If the timing was one tick off "Retarded" it would run smooth,make poor fuel
mileage and run hot.....
I suspect your are correct.A compression check WILL NOT show this problem.A
"Leakdown" test will show valve condition only.
I would suspect the camshaft is one tooth retarded.

 

[thomashanno]

I definitely smelled gas today when I was parking on the way back from
a short trip, but there was definitely nothing on the pavement and no
visible leak.

Should I take the car in and get the mechanic/dealer to take a look at
it? I'm somewhat handy and many of my friends are pretty good with
cars.

 

[Carl 1 Lucky Texan]

1997 subaru outback with 142000 miles...head gasket blew about 200
miles ago, fixed by the dealer. about 4 days ago i filled up and my
gas gauge started dropping pretty quickly. i've ruled out a leak (had
one last year) because i haven't smelled any gas after i park or seen
any puddles. sometimes i think i smell gas in my exhaust though. my
gauge was showing that i was getting about 4 mpg, but when I refilled
it was off and i was actually getting 13 mpg (as opposed to my normal
20-25). any idea what could be causing this?


thanks,
thomas

Try holding a strip of paper against the tailpipe. If it tries to 'suck
in' , could indicate improper valve timing.
I dunno if a bad Engine Temp Sensor could cause this poor mileage, but
it may have coincidentally gone bad.

Carl

 

[AS]

I think the coolant temp sensor could be defective. Does the car have
enough power?, considerably less?

 

[thomashanno]

i have not noticed less power, but it does take the car considerably
longer to start than it used to

 

[thomashanno]

is the inaccuracy of the gas gauge an indication of the problem?

 

[AS]

I would rely on the fill up system to estimate fuel consumption.

The problem could have many probable causes, among them, the coolant
temp sensor, leaky fuel injector, low tire pressure, etc. etc.

Can you have your car scanned to see if there are any codes that have
not set the check engine light yet?

Good luck!

 

[thomashanno]

i figured it can only be related to fuel since i smell gasoline, my
gauge is screwed up (read anywhere between empty and full today after
filling up).

my friend looked in my Haynes manual suggested maybe a fuel pump
problem?

 

[Carl 1 Lucky Texan]

i figured it can only be related to fuel since i smell gasoline, my
gauge is screwed up (read anywhere between empty and full today after
filling up).

my friend looked in my Haynes manual suggested maybe a fuel pump
problem?

If you smell it out the tailpipe I can only dream up about 4 ways that
could happen. The Engine (not coolant) Temp Sensor is a known issue.
Have it checked. I believe there is a fuel pressure 'regulator' at the
end of the fuel rail, maybe its stuck and fuel pressure is too high?
(anyone?). I suppose an injector could be stuck or damaged somehow?
maybe compare spark plugs and look for a distinct difference in one to
indicate the cyl. with the bad injector - or have someone test them.
Maybe some kinda vacuum or other fresh air leak is confusing the system
and the ECU is trying to compensate with more fuel?

I dunno - just some thoughts



Carl