Won't start below freezing

[Stephen J]

Okay, I promise I searched in the forum and read the whole "Common questions" thread. Sorry if I missed a thread about this, my apologies.

 

Car: 92 Legacy Automatic - 135K miles - Engine just overhauled with all the usual.

 

So obvious answer is water in the fuel I know but, there is fuel on the engine side of the filter under pressure, I have used up most of a tank of gas, put some more in from a different station, used half, put a whole bottle of Heet in it and drove it another 40 miles. Whenever it gets cold(below 32) it won't start. Just sits there and cranks. Every time I have warmed up the engine compartment and it will then start after a lot of cranking. It kinda barely eventually gets away from the starter to finally start. I just had the heater blowing directly on the filter box and MAF Sensor long enough that it was warm to the touch. Still wouldn't start. The heater is now heating the whole engine compartment.

Any ideas?

Thanks in advance,

Stephen

[OB99W]

Welcome to the forum.

 

Since you didn't mention it, I'll assume that the Check Engine light isn't illuminated (if it is, let us know). One possible cause of the problem you're experiencing is a defective ECTS (Engine Coolant Temperature Sensor). This can fool the ECU into thinking that the engine is warm when it isn't, and not provide a rich enough mixture to allow starting at cold temperatures. The ECU has no way of knowing that the ECTS is misleading it, and doesn't turn on the CEL in this case.

 

You mentioned that the engine was "just overhauled". Did you have the problem before the work was done? Does the engine seem to be cranking at the speed it usually does when it's this cold?

Edited December 5, 2010 by OB99W
corrected typo

[Stephen J]

Thank you for the welcome.

The overhaul was done just before I got it. I don't know about before unfortunately. When it is running, the check engine light is not on. It alternates on and off when cranking. Is this expected behavior?

It does seem to crank as I would expect it to.

 

Thanks for the reply.

Stephen

[Stephen J]

So I got it started. Left the a heater blowing onto the top of the engine with a piece of cardboard and a blanket over it. The intake manifold was warm to the touch. Cranked it and it didn't just fire right up but tapped the gas a couple times and it sputtered to life. The exhaust smelled very rich. Ran rough but slowly brought it up to 1500rpm and it smoothed out. Thought I would add that to see if it gave anyone any ideas.

 

Thanks,

Stephen

[nipper]

Engine Temp Sensor.

 

 

It can not tell how cold the engine is so it is flooding the engine.

 

This will not throw a code.

[Fairtax4me]

Engine Temp Sensor.

 

 

It can not tell how cold the engine is so it is flooding the engine.

 

This will not throw a code.

 

X2. Common failure on these. Think its like $15-20 for a new sensor. About 20 minutes to change it.

[Stephen J]

Thanks all for your ideas. My Subi now has a new engine temp sensor. Still won't start. It seems like if I tap the gas, just a light tap but a bunch of times, it kind of sputters then goes back to cranking with no pops. Any other ideas?

 

Thanks,

Stephen

[nipper]

Grrr i hate it when we are wrong.

 

Check the crank postion sensor as that would keep the car from starting. It will make an AC pulse in a specific pattern. i think 1 -2-1-3 but i may be wrong.

Check for spark.

Check the fuel injectors.

 

And sadly do all this wehn the car won't start.

 

This is electrical and something is opening up a bad joint someplace in the cold.

[naru]

Sounds like it is lean for some reason despite the rich smelling exhaust to me.

 

Check carefully for a vacuum leak especially in the intake tubing.

 

I would try it w/the TPS disconnected and also measure the TPS resistance.

 

3rd would be to check fuel pressure or at least change the filter.

 

4th,clean the MAF and/or try a junkyard one.

[lesstutrey]

Last car i worked on that had that problem had bad fuel pump relay, but that threw a code.... but the code said oxygen sensor.. It only acted up during cold weather starts, i would think fuel pump relay or o2 sensor would throw a code though.

[nipper]

Last car i worked on that had that problem had bad fuel pump relay, but that threw a code.... but the code said oxygen sensor.. It only acted up during cold weather starts, i would think fuel pump relay or o2 sensor would throw a code though.

 

I can see that, leaning out too much throwing off the O2 sensor

[Fairtax4me]

O2 sensor don't work when it's cold. Has to warm to about 600°F before it has any effect on fuel delivery.

 

Have you checked fuel pressure when cranking when it does this?

 

A bad crank sensor won't make it sputter slowly to life. That will get you either all or nothing. You got a fuel issue.

 

It only acted up during cold weather starts, i would think fuel pump relay or o2 sensor would throw a code though.

This is OBD1 we're talking about here. The car could be on fire and it wouldn't throw a code.

[nipper]

Sure make it difficult. OK will have to test things the old fashioned way. Unplug the O2 sensor and see if it is giving false data.OBD1 works the same way as OBDII as far as open loop and closed loop.

[johnceggleston]

i don't know about current OBD systems on any cars, subaru or other, my newest car is a 98. and obd2 is a good thing even if it was government mandated. but for subarus in the late 90s, lots of thing can go wrong, be failing, old and tired, cause problems, without throwing a code.

 

so if a sensor outright fails or is disconnected you get a CEL but if it's just not working properly you often get nothing. and then figuring it out isn't really helped by the OBD system.

 

now, back to your regular program.

[nipper]

Lets get out that ol meter and see what the engine temp control sensor is reading when it is cold. Good news is this can be done inside the house in the freezer if you want. You can watch it as it goes down in temp, especially if you have a digital thrmometer to tape to it.

[mikec03]

I have a 95 subaru that had the same problem. As the engine temperature dropped below 30 degF, the engine became harder to start. It cranked but would not start.

 

I replaced the temperature coolant sensor twice, once for the junkyard and then from advancedauto. But I don't think that it was a problem although it's very logical that it would be. The second time I replaced the sensor, I found that the PCV hose that I had to take off to get to the sensor was rock hard and cracked where it connects to the crankcase. So I think that the crack let in air making the start up combustion mixture lean. So now it starts relatively easily down to 10 degF.

 

So check that hose.

[lesstutrey]

O2 sensor don't work when it's cold. Has to warm to about 600°F before it has any effect on fuel delivery.

 

Have you checked fuel pressure when cranking when it does this?

 

A bad crank sensor won't make it sputter slowly to life. That will get you either all or nothing. You got a fuel issue.

 

 

This is OBD1 we're talking about here. The car could be on fire and it wouldn't throw a code.

 

I'd totally agree that it wouldn't throw a code except it was a '91 volvo 740 wagon with a really early version of diagnostics (6 sets of jumpers) and it was throwing a CEL and giving a code, the wrong one, but one.. but this is a ru we're talking about so maybe it wouldn't throw a code. Obviously fuel pump relay just caused a different code to throw on the volvo. Cold weather can have ill effects on old relays... but that also means it would be just about any relay

[ShawnW]

Thanks all for your ideas. My Subi now has a new engine temp sensor. Still won't start. It seems like if I tap the gas, just a light tap but a bunch of times, it kind of sputters then goes back to cranking with no pops. Any other ideas?

 

Thanks,

Stephen

You replaced the one with a blade type single wire sensor or the plug type with 2 wires going to it and a brown electrical connector?

[fiber_tek]

Okay, I promise I searched in the forum and read the whole "Common questions" thread. Sorry if I missed a thread about this, my apologies.

 

Car: 92 Legacy Automatic - 135K miles - Engine just overhauled with all the usual.

 

So obvious answer is water in the fuel I know but, there is fuel on the engine side of the filter under pressure, I have used up most of a tank of gas, put some more in from a different station, used half, put a whole bottle of Heet in it and drove it another 40 miles. Whenever it gets cold(below 32) it won't start. Just sits there and cranks. Every time I have warmed up the engine compartment and it will then start after a lot of cranking. It kinda barely eventually gets away from the starter to finally start. I just had the heater blowing directly on the filter box and MAF Sensor long enough that it was warm to the touch. Still wouldn't start. The heater is now heating the whole engine compartment.

Any ideas?

Thanks in advance,

Stephen

 

Did you find the problem with this? The reason I ask is that when the weather is below freezing my 95 OBW 2.2l likes to stutter and I wondered if it was the same thing. It hates cold weather!

[mikec03]

fiber-tex

 

Maybe this is a common problem with the 2.2's? As I posted earlier, I got the car to start down to 10 degF by replacing the cts and fixing an air leak, but it didn't fix the root cause. But what I do now is start the car with the accelerator all the way down. The car starts immediately, and I quickly release the accelerator petal. Yesterday, it started at 0 degF on the first crank. So try it.

 

Starting the engine with the accelerator at 100% is a classic remedy for a flooded engine. So does this board think that my fuel injectors are leaking, and the cold cts rich fuel set point combined with the leaking injectors is flooding the engine?

[fiber_tek]

fiber-tex

 

Maybe this is a common problem with the 2.2's? As I posted earlier, I got the car to start down to 10 degF by replacing the cts and fixing an air leak, but it didn't fix the root cause. But what I do now is start the car with the accelerator all the way down. The car starts immediately, and I quickly release the accelerator petal. Yesterday, it started at 0 degF on the first crank. So try it.

 

Starting the engine with the accelerator at 100% is a classic remedy for a flooded engine. So does this board think that my fuel injectors are leaking, and the cold cts rich fuel set point combined with the leaking injectors is flooding the engine?

 

I wish I had access to the magic tool that told me which sensor is not reading correctly, it would give me volt readings on all sensors and tell me what is going on. Doesn't the dealer have these? I wonder if I could have them do a diagnosis and call me with a quote, then go pick it up, pay for their time and do the work myself? Right now I am in the middle of cleaning the MAF sensor and IACV, replacing the CTS, and the PCV. We'll see how it goes here in a little bit. I need to get to town and buy a replacement hose that runs from the IACV to the engine, it was brittle and has become a two piece hose.

[Manarius]

fiber-tex

 

Maybe this is a common problem with the 2.2's? As I posted earlier, I got the car to start down to 10 degF by replacing the cts and fixing an air leak, but it didn't fix the root cause. But what I do now is start the car with the accelerator all the way down. The car starts immediately, and I quickly release the accelerator petal. Yesterday, it started at 0 degF on the first crank. So try it.

 

Starting the engine with the accelerator at 100% is a classic remedy for a flooded engine. So does this board think that my fuel injectors are leaking, and the cold cts rich fuel set point combined with the leaking injectors is flooding the engine?

But, since the injectors are run based on readings from the throttle position sensor, I would assume quite the opposite. That you putting your foot to the floor causes the ECU to throw more fuel at the start condition.

 

If my Subaru won't start for some reason, usually putting my foot to the floor and cranking it will get it started.

 

Has anyone mentioned the fuel pump? Maybe these cold conditions are causing the fuel pump to freeze up. Have you determined whether or not the pump is running by listening for it when you turn the key to the on position?

[WoodsWagon]

You replaced the one with a blade type single wire sensor or the plug type with 2 wires going to it and a brown electrical connector?

 

This is a very important question. One coolant temp sensor runs the gauge on the dash, that's the blade connector one. The other runs the computer, that's the 2 pin plastic click together connector one. You may have replaced the wrong one.

 

Holding the throttle 100% open puts the ECU in "clear flooded engine mode" so it shuts off the injectors while you crank the engine if you do that.

 

02 sensors will not cause no-starts.