Legacy won't start at all in 10 degrees or lower

Hello,

I have a 1993 Legacy and whenever the temperature is 10 degrees or below I cannot start the car. I have run sea-foam through the gas tank and about 10 bottles of iso-heat and I have almost ruled out water being stuck in the line. Funny thing is though, when I put a heater on the top of the engine and wrap the front of the car with a tarp, after it warms up it will start, so I know the problem is somewhere in the engine bay, not near the gas tank. Any suggestions? Fuel filter? ( I've been told that's in the gas tank so I don't think thats the problem.) Is there still possibly some water stuck in the line that has to be evacuated some other way than using additives?

maybe its your oil. try something with a lower rating. I use 5w30 here in chicago and we've hit that a few times this winter and Ive been fine.

Could you get a block heater installed?

Does it crank? first thing I would look at is your battery

any problem needs a few steps in finding what the problem is. is it cranking? do you have spark? fuel pressure? fuel delivery? need to find what is missing and go from there.

 

george

Does it crank? first thing I would look at is your battery

 

+1. The stock battery is very weak. Mine has had a couple problems turning over in extreme cold before.

i agree with battery...thats frickin cold...i wont roll over either in that kind of environment!

Agree with the oil being a contributor, especially since heat "applied" does tend to enable it to start. Also agree with battery diagnosis, including all connections at the battery end and at the engine side, including the starter, the main fuse block and the ground system. If it's rolling over and still not starting, then it's going to be fuel, air or ignition. Check that the throttle body is opening up and that it's not stuck (frozen) closed, check the spark system - including the ignitor, and that fuel is getting to the cylinders.

SBT

And don't forget to check the temperature sensors too - there may be a case of one of them actually being bad and providing a bad value back when the temperature is below 10F (I assume you don't mean 10C, which would be REALLY bad)

I have a good battery. I actually have even hooked it up to a great charger/engine crank and tried starting it at full crank...no luck. I assumed that it was something to do with the fuel line. How do I check the fuel pressure? I am curious about the temperature sensors though. What sensors should I check? Where are they located?

I have a good battery. I actually have even hooked it up to a great charger/engine crank and tried starting it at full crank...no luck. I assumed that it was something to do with the fuel line. How do I check the fuel pressure? I am curious about the temperature sensors though. What sensors should I check? Where are they located?

 

There are some to consider:

Coolant Temperature sensor.

Intake Temperature sensor.

Combined Manifold Pressure/Intake Temperature sensor.

Mass Air Flow/Intake Temperature sensor.

 

And notice that not all of the above exists on all cars, only some, and which ones depends on the car model, year and market.

 

You shall be aware that it can be a different sensor that is your problem, and if you can't read any code you can do it the manual way: Try to locate each one at a time, heat it with a hairdryer so it becomes warm and try to start the car. This may narrow it down for you.

 

For the following take help of a friend...

 

It is also a good idea to do basic checks and see if the injectors get their pulse by connecting a LED and a resistor over the wires. Same with ignition coils low-voltage end. Best is to use two LED:s in opposite directions since then you don't have to worry about polarity. Start with the injectors and then check the coils since even the low voltage end can have a considerable voltage, but burning a pair of LED:s is a cheap mishap. The high voltage can also be tested by a simple test, pull one cable insert a spark plug and secure it without holding it and see if a spark comes up when the engine is cranked.

 

In case you have pulses on each location it may be that you actually don't have fuel pressure. Are you able to check if the pump is running? Open the filler cap and have a friend turn on the ignition but NOT start the engine (all fans and other noise devices off) then you shall be able to hear the pump for about two seconds through the filler pipe. If not it's possible that something in that circuit is dead.

 

There is a fuel pump relay in the passenger compartment. Either near the fuse box or behind the right kick panel. It is also possible that it is in the engine compartment. (hide and seek) As soon as you find it there shall be four wires, and according to the schematic I have the wire to the pump shall be brown.

 

Anyway - you can always check if the relay pulls or not. If it pulls but the pump doesn't start it's likely to be the pump. You can also check if there is power arriving to the pump. There shall be a connector at the gas tank where you can check if it gets power.

 

If the relay doesn't pull it may be the relay, or it is the MPFI control unit. It can also be oxides on contacts or even an almost completely corroded wire.

 

Many places to look, many possible causes. Start with the simple tests.

10 is not that cold. It is not the oil, you have a spark or fuel problem.

Yeah my 79 malibu when i had the stock 6 cylinder would start in -30, its not the oil lol, who said that

To the OP:

 

Depress the accelerator 1/3 of the way to the floor. Dollars to donuts your car will start (assuming it is capable of cranking). If it doesn't, hold the accelerator against the firewall. You could have leaky injectors that are creating a flooded condition. Holding the pedal to the floor signals the ECU to try a starting procedure for a flooded engine.

so I know the problem is somewhere in the engine bay, not near the gas tank. Any suggestions? Fuel filter? ( I've been told that's in the gas tank so I don't think thats the problem.)

there is a fuel filter under the hood. its about the size of a small coke can with an in and out tube on the top.

its on the drivers side right behind the windshield washer filler cap. it has a flip lock to hold it in place and has 2 hoses going across the top and one going in and one going out. the 2 that cross the top are part of the venting system i think, just push them out of the way and you can pull the filter after disconnecting the fuel lines.

caution!!!!!

the fuel system is under presser, so some fuel will likely leak out, as well as the filter is full of fuel. so be ready for it.

If the relay doesn't pull it may be the relay, or it is the MPFI control unit. It can also be oxides on contacts or even an almost completely corroded wire.

 

what do you mean by if it pulls ?????

im haveing fuel problems also. but mine is pump on or off depending on the mood of the car not the temp ????

I hate to revive an old thread, but I’m having a similar issue. Did you ever find the source of the issue? Mine will not start once the temp hits 30 degrees or less. Absolutely no spark. I disabled the alarm, now I get spark and still won’t start. I found out that if I cycle the key 5 or 5 or 6 times (not to start), it usually fires up. It’s really frustrating.

I hate to revive an old thread, but I’m having a similar issue. Did you ever find the source of the issue? Mine will not start once the temp hits 30 degrees or less. Absolutely no spark. I disabled the alarm, now I get spark and still won’t start. I found out that if I cycle the key 5 or 5 or 6 times (not to start), it usually fires up. It’s really frustrating.

 

A really, really old thread ....

 

This might help you - https://legacygt.com/forums/showthread.php/2008-forester-2-5-na-crank-no-start-276692.html

Thanks! You are a life saver!

Thought I’d throw an update to my issue here. Since replacing the head unit/ dual auto climate unit, all my dead battery and cold start issues have gone away.