1994 Impreza Question

[Trout]

I have the 1994 Subaru Impreza - 4 door - automatic

When the car is cold and I have to drive on the highway,
it gets to the 2500 rpm area and about 55mph and will
not jump into the last gear for the longest time.

What is doing this ? Temperature sensor of some kind ?

 

[Joe Kultgen]

I have the 1994 Subaru Impreza - 4 door - automatic

When the car is cold and I have to drive on the highway,
it gets to the 2500 rpm area and about 55mph and will
not jump into the last gear for the longest time.

What is doing this ? Temperature sensor of some kind ?

Yes.

The transmission computer doesn't let it go into top gear until it warms
up. Don't let it bother you.

 

[Trout]

The transmission computer doesn't let it go into top gear until it warms
up. Don't let it bother you.

Do you know where the thermal sensor is on the
transmission and is hard to replace ?

I'd rather get up to speed on the highway instead
of waiting 10 or more minutes for the trans to
get into the highest gear.

 

[Mark Olson]

Do you know where the thermal sensor is on the
transmission and is hard to replace ?

I'd rather get up to speed on the highway instead
of waiting 10 or more minutes for the trans to
get into the highest gear.

Assuming there isn't actually something wrong with the sensor...

What makes you think getting into top gear[1] before the engine and
transmission is warmed up is better for the engine than doing it
the way Subaru's engineers designed it?

[1] Is it really keeping the trans out of 4th gear, or is it simply
preventing the lockup torque converter clutch from engaging?

 

[Joe Kultgen]

Do you know where the thermal sensor is on the
transmission and is hard to replace ?

I'd rather get up to speed on the highway instead
of waiting 10 or more minutes for the trans to
get into the highest gear.

Not sure I understand the problem.

At different times I've owned both a '93 Imprezza and a '93 Loyale.
Both had 1.8 liter engines of slightly different design. Either one
would go directly from a cold start to 75 MPH on the freeway if I chose
to abuse them that way. The main difference is that cruise RPM on the
Imprezza would drop to around 3,000 after a two mile or so warm up. My
Loyale only had a three speed automatic and cruised around 4,300 RPM
regardless of engine temp. What exactly do you mean by "up to speed"?

If it's actually taking you ten minutes to get that final shift you may
have a bad thermostat. If it's stuck partially open the engine won't
warm up as quickly as it's supposed to. Also keep in mind that a 1.8
four cylinder doesn't burn enough fuel to make a lot of heat and the
Imprezza has a pretty large heater core. The thermostat only controls
what percentage of the coolant flow is routed through the radiator.
Here in Wisconsin I've seen winter days when running the heater blower
full blast would actually pull the temp gauge out the bottom of the
operating range on an engine that was already warm! :-(

Later,
Joe

 

[Phil]

What makes you think getting into top gear[1] before the

engine and transmission is warmed up is better for the
engine than doing it the way Subaru's engineers designed it?

Every other manufacturer can do it ok so it would be faintly ridiculous
for Subaru to make such a mess of it.

 

[Joe Kultgen]

What makes you think getting into top gear[1] before the
engine and transmission is warmed up is better for the
engine than doing it the way Subaru's engineers designed it?

Every other manufacturer can do it ok so it would be faintly ridiculous
for Subaru to make such a mess of it.

Different companies have different design priorities.

Do you have a problem with an auto maker designing a rev limit into the ECM
to keep some wahoo from seeing how far past red line he can go before the
rods come out? How about antilock brakes? Traction control so you can't
floor board it and spin the tires?

How does using the control circuitry for the automatic trans to compensate
for owner indifference or abuse "make such a mess of it"?

If the original poster cannot get the car to exceed 55 MPH until it has
warmed up, there is a mechanical issue with his particular vehicle that
needs to be resolved. If he chooses not to exceed 2,500 RPM on a car that
red lines at 6,500 why blame the engineering department for his driving
style?

 

[strchild]

I know somebody with a FORD Aspire automatic, and it will not even allow you
to shift into gear and drive *at all* until you have warmed the car up for
almost five minutes. Of course, yes, you can override that feature, but at
what cost?

~Brian

What makes you think getting into top gear[1] before the
engine and transmission is warmed up is better for the
engine than doing it the way Subaru's engineers designed it?

Every other manufacturer can do it ok so it would be faintly ridiculous
for Subaru to make such a mess of it.

 

[strchild]

Been having the warm-up problem here the last few days with my 93 Impreza,
too. The car will cool off from running temp when you are going down any
sort of grade, even with the heater off. Like you said, just not burning
enough fuel to make the heat. But I can also get up to any speed I want
while the car is cold, if I chose to abuse it that way. Only takes about a
minute or so on the highway at 55+ to warm it up to running temp, and that's
not too many RPM's.

~Brian

 

[Joe Kultgen]

Been having the warm-up problem here the last few days with my 93
Impreza, too. The car will cool off from running temp when you are
going down any sort of grade, even with the heater off. Like you
said, just not burning enough fuel to make the heat. But I can also
get up to any speed I want while the car is cold, if I chose to abuse
it that way. Only takes about a minute or so on the highway at 55+ to
warm it up to running temp, and that's not too many RPM's.

~Brian

This really sounds like a bad thermostat. It's not unusual for them to
fail in a way that keeps them from closing properly. A thermostat that
won't open will toast your engine fast, one that won't close will mess it
up just as bad, but takes a much longer time to do it. If your engine is
running below the proper operating temp it drastically accelerates wear and
tear. Running that way for an extended time could literally take tens of
thousands of miles off the life of your engine. The part itself should be
less than $20 even from the dealer and this is one area where OEM is the
way to go. I've heard of so many problems with aftermarket Subaru
thermostats I wouldn't try to save a buck that way.

 

[strchild]

No, I think it's normal to me. Just unusually cold weather and I live atop
a big hill. Drops about 1000' in elevation within a half mile. Going down
the hills around here can pull the temp down, but it never bottoms out.
Never overheats or otherwise runs too cool when it's not idling it's way
down hills also. (-;

~Brian

 

[Joe Kultgen]

No, I think it's normal to me. Just unusually cold weather and I live
atop a big hill. Drops about 1000' in elevation within a half mile.
Going down the hills around here can pull the temp down, but it never
bottoms out. Never overheats or otherwise runs too cool when it's not
idling it's way down hills also. (-;

~Brian

Guess I'm just a hopeless flatlander. I'd have to drive 500 miles to find
a stretch of freeway where I could speed up by shifting into neutral.

Joe

 

[strchild]

Well, maybe, but I'll bet you have plenty of fun straightaways you can gun
it on. Makes them 500 miles just melt away! (-;

~Brian

 

[Phil]

What makes you think getting into top gear[1] before the

Different companies have different design priorities.

Do you have a problem with an auto maker designing a rev limit into
the ECM to keep some wahoo from seeing how far past red line he
can go before the rods come out?

Yes, if it prevented the driver from exceeding 2,500rpm, as that would
not be a design priority, that would just be a bad design.

I'm working from the assumption that Subaru wouldn't do anything that
stupid though, and that it's a mechanical fault of some kind.

How about antilock brakes?

Hardly the same thing.

Traction control so you can't floor board it and spin the tires?

I certainly have no love for traction control, but that's a seperate
issue and is largely down to personal preference.

 

[Joe Kultgen]

What makes you think getting into top gear[1] before the
engine and transmission is warmed up is better for the
engine than doing it the way Subaru's engineers designed it?

Every other manufacturer can do it ok so it would be faintly
ridiculous for Subaru to make such a mess of it.

Different companies have different design priorities.

Do you have a problem with an auto maker designing a rev limit into
the ECM to keep some wahoo from seeing how far past red line he
can go before the rods come out?

Yes, if it prevented the driver from exceeding 2,500rpm, as that would
not be a design priority, that would just be a bad design.

I'm working from the assumption that Subaru wouldn't do anything that
stupid though, and that it's a mechanical fault of some kind.

Yep.

That's why I asked the OP for more info. The one I had went past 2,500
easily but wouldn't do the final shift until the coolant and presumably the
ATF temp was in the operating range. That's a feature. If it isn't
letting him exceed 55 MPH until it warms up that's a malf and needs to be
investigated.