legacycentral bbs

Hey guys,

a few months ago I started to experience random starting issues. It was only when the engine was warmed up, and I would try to start the engine. It was probably every 1 in 20 warm starts that it did this.

It just cranked and cranked with no sound of fuel ignition. I would let it sit for a minute and then it may start after 4-5 seconds of cranking.

It starts perfectly EVERY time from cold!

The problem seems to be a bit more frequent now, so I'm really wanting to get this fixed soon.

Any ideas?

Oh and I hear the fuel pump pressure up every time I go to start it.

Thanks.

I'd say replace your coolant temperature sensor. It's a real PITA on the turbo engine, but it's designed to "protect" your engine from starting if it's too hot to run. But when the engine is cold, then the temp sensor isn't stopping your engine from starting because the coolant is cold.

Interesting. I'll look into doing that. Is there a way to test the sensor?

You would think that it wouldn't even let the starter crank if a sensor is telling the engine not to start? Or would that make too much sense?

It makes a little sense, but then it doesn't. Imagine how you'd freak out if suddenly your car wouldn't even crank if it was warm. This way you get a good signal from the starter, but no spark from the ECU. I'd say that's why they did it. And I don't think there's any good way to test the sensor. It's a 6 dollar part. Just a pain to replace cuz of the turbo being in the way.

The tests for the sensor don't always show up that the sensor is bad. You can get the sensor for about $20 from the dealership or www.subarugenuineparts.com

K thanks guys, I'm pretty sure you are right with the sensor.

I find that the odd time I go to start my engine warm, the fans come on if I wait a second (usually the time it takes for fuel pump to turn on and off). If I try to start it during that time it will will just crank. If I wait for the fans to turn off, it starts right up with very minor hesitation.

If the fans don't come on, it always starts.

So do I need to drain the coolant to do this sensor change? Think I'm hurting anything if I just wait for the fans to do their cycle until the spring?

Thanks

Is the AC or the defrost on when the fans come on? If not, then it's a good indication that the coolant temp sensor is not working right. You really need to replace it. A lot in the ECU is based off the coolant temp sensor readings, air fuel ratio is the biggest, which affects drivability, MPG, etc.

Some people don't bother draining the coolant. Some will drain out. You can drain a little bit out so it drops below the level of the coolant temp sensor.