Subaru 2000 Legacy Cold Start Problems

The car was manufactured in Canada, however the engine was replaced locally before i bought it. My understanding is that it is a 2.5L single cam. During warm weather the engine runs great. At 30 degrees it fires irratic and then starts. When it is in the throws of starting the engine check light flashes and the what I believe is the main relay drops in and out. As it get colder it becomes much more difficult to start to the point where at approximately 10 degrees F it plain will not fire. At this point I get frustrated and start pulling sensors. At temperatures above 10degreesF this seems to reset the computer and will it fires and starts. I have replaced the coolant temp sensor to no avail. I have brought the air temp inside to warm to no avail. In the nether world of 10 degrees to 30 degrees disconnecting a sensor, attempting to start seems to work with no regularity as to which sensor (ie. air temp, coolant temp, purge solenoid, throttle valve). When the car does start, it seems to fire on half it's cylinders for a bit as it chugs to a point where I can finally give it enough gas without stalling it. Once it starts, it runs beautifully no matter what the outside temp is. My second hand understanding is that there is no spark when it wont start. Not sure if the coil is powered. It seems to be that the computer is not allowing it to fire. HELP! Please!

Sincerely, David

Reply to
Darradserv
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Simple as this sounds I would do it anyway. Remove all ground connections, sand/clean and reattach. Do this not only to the battery but, to ALL connections on the front spring/shock tower, starter and engine block. Relays dropping out are a sign of low voltage either a bad battery cell or poor connections. Let us know it or what helps solve this issue. Ed

Reply to
Edward Hayes

Have any codes been pulled from the ECU? I THINK I recall some year/models having cold sensitive crank angle sensors.

good luck

Carl

Reply to
Carl 1 Lucky Texan

Did I miss where you had the battery tested to determine if it has the cold cranking amps needed at low[er] temperatures? Even if the car starts, a weak battery can cause troubles with all the circuitry. My alternator went bust so my battery wasn't getting charged while driving. Before the battery was no longer able to do so, it could still start the car but the electronics were screwed up (the running voltage was too low because of the bad alternator). Did you put a voltmeter across the battery before starting, during starting, and after starting to see what voltage was available?

Reply to
Vanguard

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