Hello,

I would like ask, when is more like -15 C, motor dies 5-10 seconds after start.

What I did:

1.tappet clearance -ok

2. IACV ventil + engine intake canal  - clear - OK

3. manifold vacuum -OK

4. fuel pressure - ok

5. air valve set to 0,39 V -ok

6. subaru free ssm logs - all looks ok, when I compare with another subaru start (senzors, temperature,ERG,...)

Have you any idea?

Thanks

After it dies the first time does it start right back up again? Any trouble starting after it's warm? I don't know the fuel quality in Slovakia, but you could just have some water freezing in your fuel lines. Try adding some dry gas if that's the case.

Yes, second start is ok. If warm, start is also ok. 

Water in fuel could be, but it doesnt explain, why is first start ok. Only after start it dies. Also why it doesnt die when f.e. only -10 C.

I have fuel dumper before fuel filter, should be after filter?

That would depend on where in the lines it's freezing I suppose. The fuel in the fuel rails wouldn't freeze because of the volume of fuel that's in there. Enough to run the car for a few seconds before it runs out. it would be difficult to determine exactly where it's freezing but I would assume it's probably somewhere under the car closest to the ground. If that's the issue.

If you use some dry gas in your tank and the problem goes away then you know thats the cause of the stalling.

It's probably a fuel trim issue - the computer has to learn and has no O2 sensor at that temp. You may need to remove the injectors and clean/flow test them, and also do a smoke test of the engine cold to find any intake manifold leaks that could be contributing to an erroneous MAF reading. Often the injector seals will leak at low temps causing fuel and air leaks. Removing them, cleaning, flow testing, and seal replacement will all help.

 

GD

Wouldn't those symptoms continue persistently on each consecutive start until the engine was warm if that were the case? even a minuscule manifold leak would continue to create symptoms for at least a minute or so wouldn't it? Same with the injector seals until they warmed up and the likelihood of all of the injector deals leaking isn't that great. Granted, I don't live in sub zero temps so what do I know. I would still eliminate the possibility of frozen lines before I rip the fuel rails off the car.

• Re

GreaseMonkey:

No,all other starts this cold day are ok always.Next morning again dies after start. Strange. 

Fuel line frozen could be the reason. After few seconds runs it out as you wrote. Also I had read, that fuel pump is stoped after start for few seconds...probably for safety reasons.

But when I step gas pedal, it is runnig good. Also it doesnt explain that next start is ok.  

I was solving fuel pressure regulator, if is forzen, than maybe I have rich mixture. But regulator seems ok.

GeneralDisorder:

Manifoldd seems ok, when I look to logs.Foir sure I will try test with smoke and I will try clean injectors.I hope thats help.

Thanks for hints 

Another small thing you can try is to turn the key on and off a couple times before you start it to prime the fuel pump. The increase and drop in pressure itself could be enough to free up the fuel flow IF the root cause is a frozen line.

Wouldn't those symptoms continue persistently on each consecutive start until the engine was warm if that were the case? even a minuscule manifold leak would continue to create symptoms for at least a minute or so wouldn't it? Same with the injector seals until they warmed up and the likelihood of all of the injector deals leaking isn't that great. Granted, I don't live in sub zero temps so what do I know. I would still eliminate the possibility of frozen lines before I rip the fuel rails off the car.

The computer will trim the fuel to compensate so it may not occur for long. Injector to manifold seals can leak enough air to cause fuel trim codes. P0171 (lean bank 1) can be caused by a relatively small leak at idle. Just had an 03 WRX in the shop with a lean code for two leaking injector snubbers.

 

GD

Edited February 13, 20179 yr by GeneralDisorder

I must have misread. I thought he had no codes. But still can't figure out why the car would shut off if that were the case. He didn't mention it running rough either. Oh well

Could be the idle control valve needs cleaned. We have had some luck with dipping them in a sonic cleaning tank for 15 minutes. I say some because sometimes you just need to replace them. Cleaned one today on an 04 WRX and it worked perfectly afterward. Don't trying cleaning them without the ultrasonic tank though. It's pretty much futile in my experience. Mine came as part of my injector flow bench but you can buy them cheap. I run simple green in mine per the recommendations of the injector bench manufacturer.

 

GD

Edited February 15, 20179 yr by GeneralDisorder

Yes, i didn't have any trouble code for this start problem.

IACV ventil - step motor with scrol is ok, I had clean, also I did try last year another one for winter test - the same result. So I  exclusive IACV ventil. 

 

One thing when I sudden step gas pedal for 5 seconds before It dies, then all is ok, after release pedal doesn't dies, rpm are normal. 

in Slovakia - could this model be drive-by-wire?

It wouldn't have an IACV if it were DBW.

 

GD

DOH! - of course - that would be under ecu control, I forgot.