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Mysterious starting issue on my Subaru
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impreza808
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Feb 20, 2017, 2:33 PM
Post #1 of 19
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Mysterious starting issue on my Subaru
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I have a 2008 Subaru Impreza WRX STI.
I have this starting issue that been plaguing me for some time now. None of the local mechanics could not figure it out.
Basically, the car will take up to 5sec to start, when the engine is shut off, and wait about 15min, all the way to overnight. If I start the engine within a couple min, it will start quick(it does get longer as more time passes). If I try to start it immediately after shut down, it fires up like brand new.
However, if I let it sit for a longer time, say couple of days, it will fire up immediately. Also, leaving the cylinder open, like when I changed out the spark plugs, also allows for fast starts.
Two of the plugs looked black, but was also wet. Couldn't tell if it was oil or gas.
As for the fluids, coolant looks good and oil doesn't look milky.
I'd assume if there was a fluid leak into the cylinders, I would leave a trail of smoke, but none of that either. EXCEPT on those hard starts when the car has been parked for several hours. There would a initial puff of whitish smoke, and none thereafter.
From the information we have, what could be the possible culprit?
Thanks
(This post was edited by impreza808 on Feb 20, 2017, 2:42 PM)
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kev2
Veteran
Feb 20, 2017, 3:07 PM
Post #2 of 19
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Re: Mysterious starting issue on my Subaru
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Confusing - hopefully just an oops.
" None of the local mechanics could not figure it out. "
So they all figured it out - just will not tell you?
Anyway -
Scan for codes even if light is out.
fuel pressure test then with KOEO observe fuel pressure drop ie drops Xpsi in 5min.
Any aftermarket BS or modifications ?
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Tom Greenleaf
Ultimate Carjunky
/ Moderator
Feb 20, 2017, 11:57 PM
Post #3 of 19
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Re: Mysterious starting issue on my Subaru
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! Two cylinder's had fouled plugs and nobody has a clue? That's the trouble. Fuel, oil could foul them, coolant generally if slow cleans them. Any could appear as a smoke upon start up or continuously if bad enough while running the color says which fluid is burning. White - coolant, blueish is oil and black is usually unburned fuel,
T
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impreza808
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Feb 21, 2017, 10:54 AM
Post #4 of 19
(2013 views)
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Re: Mysterious starting issue on my Subaru
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! Two cylinder's had fouled plugs and nobody has a clue? That's the trouble. Fuel, oil could foul them, coolant generally if slow cleans them. Any could appear as a smoke upon start up or continuously if bad enough while running the color says which fluid is burning. White - coolant, blueish is oil and black is usually unburned fuel,
T
yeah, weird eh? I had two shops look at them, and they just swapped the plugs and called it a day. Spent almost $500 just to get the plugs changed, and it didn't even fix the starting issue that I originally brought the car for. When I asked them that there must be an underlying issue causing this, and they said it is normal for a modded car to do this. Normal, meaning the plugs get fouled up to the point of failure within a couple months? I had this tune on the car for 6 years with no issues, please. It is a very mild one, just a downpipe and a tune to get a little more HP and smooth out the terrible factory one. I did swap out the plugs two years ago myself, and they looked fine at that time.
I did swap around the plugs, and the misfire followed the plug, so at least that was the cause for the P303 code. But I still need to find out why this is happening. This incident of the plugs being fouled up and the starting issue is probably related. The smoke that comes out is greyish, and smells like unburnt gasoline. The smell of the wet plugs that came out smells like gas too. But I thought unburnt gas comes out black?
I am scheduling a leak down test soon.
(This post was edited by impreza808 on Feb 21, 2017, 11:03 AM)
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Discretesignals
Ultimate Carjunky
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Feb 21, 2017, 11:06 AM
Post #5 of 19
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Re: Mysterious starting issue on my Subaru
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Which two cylinders have wet plugs?
Since we volunteer our time and knowledge, we ask for you to please follow up when a problem is resolved.
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kev2
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Feb 21, 2017, 11:33 AM
Post #7 of 19
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Re: Mysterious starting issue on my Subaru
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"normal for a modded car to do this."
A down pipe? a non factory tune - explaining this may help ?
Hopefully there is NO CAI or K&N type BS....it all matters.
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Discretesignals
Ultimate Carjunky
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Feb 21, 2017, 6:54 PM
Post #9 of 19
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Re: Mysterious starting issue on my Subaru
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Have you checked to make sure that the fuel pressure regulator isn't leaking into the intake manifold via the vacuum hose?
Since we volunteer our time and knowledge, we ask for you to please follow up when a problem is resolved.
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impreza808
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Feb 22, 2017, 11:27 AM
Post #10 of 19
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Re: Mysterious starting issue on my Subaru
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Tried that, left the vacuum hose out to see if any fuel starts spewing from it. Watched for about 5min, nothing came out. Is that long enough?
I am planning to do a fuel pressure test this weekend. Then get the leak down test next week.
Got an image of the failing plug last night.
The plug smelled pretty strong of gasoline, and the threads were wet from it.
http://imgur.com/3Db5UBl
I replaced it with an old one from a while back, and the misfire is gone now.
Still need to find out the root cause of the hard start and fouled up plugs.
(This post was edited by impreza808 on Feb 22, 2017, 11:37 AM)
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impreza808
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Feb 22, 2017, 11:35 AM
Post #11 of 19
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Re: Mysterious starting issue on my Subaru
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Just a thought, the O2 sensor is reading around 14.7 AFR which is ideal. But how can it read 14.7 when the car smells like it is running rich?
(This post was edited by impreza808 on Feb 22, 2017, 11:36 AM)
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kev2
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Feb 22, 2017, 12:17 PM
Post #12 of 19
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Re: Mysterious starting issue on my Subaru
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your not understanding - the fuel pressure test key in run position - KOEO*- observe and record the pressure - the pump will turn off after @1 minute, then observe the pressure drop, drops Xpsi in 5min - I suspect you will see a problem here.
The KOEO position will check leaking or wiring issues with injectors. same test just 5 extra minutes...
What are the o2 sensor voltages?
What are fuel trims?
WHat is Ect ?
*KOEO Key On Eng Off
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impreza808
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Feb 27, 2017, 6:10 PM
Post #13 of 19
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Re: Mysterious starting issue on my Subaru
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So I did the fuel pressure test and got a leak down test done at the dealer.
For the fuel pressure, the system maintains the factory spec of 33-34psi at idle. When I turn the key off, and come back 15 min later, the pressure is 15-20psi. Did this five times, and the numbers are consistent. Overnight, the pressure eventually went to zero.
The leak down test came out negative, all cylinders maintained a similar pressure.
They saw the wet plugs, and suspected that the delayed hard start is due to the fuel slowly leaking into the cyclinders, creating a semi flooded condition. They suggested I do an injector clean at a specialty shop.
But do you guys think it is faster to just get a new set of injectors than trying to figure out which ones are acting up and cleaning it?
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impreza808
User
Apr 18, 2017, 2:50 PM
Post #14 of 19
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Re: Mysterious starting issue on my Subaru
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UPDATE:
Finally got my injectors replaced and my car starts immediately after the said problem times. No smoke either. Car feels smoother overall.
The technician said that my injectors looked like crap, especially one them
Question is, how did it get so bad?
(This post was edited by impreza808 on Apr 18, 2017, 2:51 PM)
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Hammer Time
Ultimate Carjunky
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Apr 18, 2017, 3:12 PM
Post #15 of 19
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Re: Mysterious starting issue on my Subaru
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By the looks of that nozzle and O-ring, I'd say old age, heat and crappy gas.
I didn't see anywhere how many miles are on this car.
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We offer help in answering questions, clarifying things or giving advice but we are not a substitute for an on-site inspection by a professional.
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impreza808
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Apr 18, 2017, 3:42 PM
Post #16 of 19
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Re: Mysterious starting issue on my Subaru
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Car has almost 80K miles.
This car has only drank Shell gas from day one. Can there be other factors that turn good gas bad? Could running injector cleaner from time to time slow down this deteriorating process?
(This post was edited by impreza808 on Apr 18, 2017, 3:44 PM)
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Hammer Time
Ultimate Carjunky
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Apr 18, 2017, 3:44 PM
Post #17 of 19
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Re: Mysterious starting issue on my Subaru
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Ethanol
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We offer help in answering questions, clarifying things or giving advice but we are not a substitute for an on-site inspection by a professional.
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impreza808
User
Apr 18, 2017, 4:32 PM
Post #18 of 19
(1778 views)
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Re: Mysterious starting issue on my Subaru
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Read up that, and it seems it does mess up your fuel system. Some people pointed out that using products like techron/seafoam will lessen the effects of ethanol. What's your take on that?
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Tom Greenleaf
Ultimate Carjunky
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Apr 18, 2017, 4:43 PM
Post #19 of 19
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Re: Mysterious starting issue on my Subaru
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I personally like SeaFoam products. Additives are sold with all sorts of claims up to ones the cancel the ill effects of ethanol and I don't believe that yet. In fact most additives you see for assorted quick fixes are probably worse then not using them at all and knowing which are real or not about impossible to know for sure,
T
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