Impreza WRX running bad when cold.

[Daz Ellerington]

Hi.

I've got a 1995 Impreza WRX import and it's running very lumpy when the
engine's cold. The ECU keeps telling me that it's the water temp sensor but
I'm getting fed up with changing that. Once the engine has warmed up again
it runs 'smoother' but seems to have lost some power.

Has any of you come across this before and can shed some light on it? Any
help would be apreciated.

Many thanks in advance.

Daz.

 

[Remco]

Hi.

I've got a 1995 Impreza WRX import and it's running very lumpy when the
engine's cold. The ECU keeps telling me that it's the water temp sensor but
I'm getting fed up with changing that. Once the engine has warmed up again
it runs 'smoother' but seems to have lost some power.

Has any of you come across this before and can shed some light on it? Any
help would be apreciated.

Many thanks in advance.

Daz.

I've seen it where a coolant sensor will cause the car to not run right
or make it very hard to start. The computer does need to be reset after
you replace it - did you do that?
(connect the two green jumpers under the steering wheel together while
turning the key to start position does it, I seem to remember).

Remco

 

[Utahcherokee01]

You may also want to look into the possability of a vacume leak.. my 93
imp was loaded up with around 800+ in parts that the computer kept
saying were bad then I had a decent Mechanic look at the engine for 5
minutes and found a tiny vacume leak.. cut the bad section of the hose
out and hooked it back up.. Had all my power back and no more rough
starts... Paris (my mechanic) said that subaru's are notorious for
running like crap and giving false readings on parts due to small
vacume leaks

 

[Remco]

You may also want to look into the possability of a vacume leak.. my 93
imp was loaded up with around 800+ in parts that the computer kept
saying were bad then I had a decent Mechanic look at the engine for 5
minutes and found a tiny vacume leak.. cut the bad section of the hose
out and hooked it back up.. Had all my power back and no more rough
starts... Paris (my mechanic) said that subaru's are notorious for
running like crap and giving false readings on parts due to small
vacume leaks

That's a good point. I've had Saabs and they had similar sensitivities.

To detect one, get some starter spray (like ether) and spray it around
suspect areas with the engine running. When you detect a brief change
in the way the engine runs, you've found your leak.

Remco

 

[Daz Ellerington]

thanks guys

 

[William S. Hubbard]

It's the crappy precatalyst. Usually, once the car is warmed up it
runs good.