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Premium Member
2008 JDM Outback 3.0R, 5EAT
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410 Posts
Discussion Starter #1
hi, this is a new problem that turned up after replacing coolant and having the injectors pro cleaned.

when the engine is fully cold or fully hot she starts great every time - within a second of pushing the go button.

however ... when the dash temp gauge shows between 1/4 and 1/3 cranking can take 5 to 10 seconds though doesn't fail to start.

the injectors are dry externally and i burped the coolant system with a no spill funnel (maybe not well enough?) . also replaced the coolant temp sensor with no effect.

no check engine light, everything is stock and oem. what do you think could be causing this issue please ?
 

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Registered
06 Outback 2.5i
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405 Posts
Coolant shouldn't affect starting, other than maybe the temp of the engine.

I'd focus on the injectors and electrical systems. How long were the injectors out? All your grounds ok/clean?
 

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Premium Member
2008 JDM Outback 3.0R, 5EAT
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410 Posts
Discussion Starter #3
thanks, injectors were away for 3 days to the cleaning company. the grounds have been ok although the injector connectors were a little tight for the first disconnect i hope and don't think i did any damage there
 

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Registered
2008 OB Limited 2.5i, Portland OR USA
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6,156 Posts
The puzzler here is the narrow temperature range that it occurs - not hot, not cold, but in the middle.

Check the fuel supply from the pump perhaps?
 

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Premium Member
2008 JDM Outback 3.0R, 5EAT
Joined
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410 Posts
Discussion Starter #5
thanks, i'll pick up a fuel pressure test kit. also the metal fuel pipe protectors are removed, i don't know if that would affect anything. and the new o-rings were supplied by the injector cleaning company, i'll replace the o-rings with subaru in case the material or dimensions are very slightly different.
 

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Registered
06 OBW 2.5, 05 Forester, had 03 H6 OBW
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5,935 Posts
Was the computer reset after the injector cleaning?

Another thought, if an injector were now leaking, could be it starts cold because it needs to be a bit richer when cold, and it starts hot because there's no extra enrichment, but in between the computer still adds some enrichment and it's a little too rich to start easily.
 

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2012 OB , 2017 Impreza
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3,287 Posts
It is not unusual for an engine to have 'troubles' starting when its temperature is between cold/hot. Personally, I try VERY hard to never have my engines within this range (cars, lawnmower, tractor, weedwacker, leafblower.... etc)

With a fuel-injected engine, it is ALWAYS better to turn the key to "ON" and wait a few seconds before cranking the engine. This allows the fuel-pressure to build up before you begin a starting-sequence.

In your case, I would rule out the antifreeze and focus on the INJECTORS which were recently removed for cleaning. As mentioned above, if one of the injectors were 'bleeding off' the fuel-pressure while the engine was shutdown, it would take a moment for the pressure to rebuild before the engine would restart.

ALSO, a leaking injector would tend to put excessive fuel into intake plenum while parked which would make engine harder to restart.
 

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On the Super Mod Squad
02 Pair: 3.0 VDC Wag & 2.5 Limited Sedan
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26,212 Posts
not on subarus:

but
on old VW and Hondas I have had to change relays in the under the hood fuse box due to the car not being able to start on the 2nd time in the day.

like Starts right up before the sun comes over the tree line.

but after the car has run for a while to regular temp, and then the car has sat in a hot parking lot under the sun,.

...just too much heat for the relay to adjust and work like they should.

...frustrating to not know, :|

but then such a quick and easy fix.:smile2: (and back in the day "CHEAP")
 

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Premium Member
2008 JDM Outback 3.0R, 5EAT
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410 Posts
Discussion Starter #9
Thanks for these messages. After reading through I went back to the car one hour after parking up and didn't start the engine until the ignition had been turned on a good 10 to 15 seconds (and hoped it would then start easily). But nup the same long cranking occurred before firing - tried this three times over with the same result.

Also noted the fuel trims at idle for both banks are within +-3% (computer reset when the battery was disconnected for the injector work). The issue only started at that time, previously this wouldn't be a problem we'd jump into the car, foot to the brake, press the start engine button and go.
 

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Registered
2005 18psi supercharged U5 Outback w/207k+ miles
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757 Posts
My car does the same thing but mine are larger, not stock injectors.

It starts great on first start of the day and after that, it will start fine if i re-start within a few minutes (hot),but after sitting for say an hour or 2 it takes a few seconds of cranking to get going. I figured mine was due to not getting the engine coolant temp cranking tables quite right but maybe we have the same problem somehow? An installation issue?
 

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Premium Member
2008 JDM Outback 3.0R, 5EAT
Joined
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410 Posts
Discussion Starter #11
My car does the same thing but mine are larger, not stock injectors.

It starts great on first start of the day and after that, it will start fine if i re-start within a few minutes (hot),but after sitting for say an hour or 2 it takes a few seconds of cranking to get going. I figured mine was due to not getting the engine coolant temp cranking tables quite right but maybe we have the same problem somehow? An installation issue?
Hi that does sound very similar. Were there any changes to the car before this problem arrived? For me it was triggered around the same time as installing the cleaned injectors and also I burped the coolant around that time.
 

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Premium Member
2008 JDM Outback 3.0R, 5EAT
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410 Posts
Discussion Starter #12
I've been keeping an eye on fuel economy which has dropped a little especially around town and at idle with a touch of smoke from the tailpipes. I'm waiting on the fuel pressure test kit to be delivered and I think these symptoms also point to a leaky injector ?
 

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2015 Outback 2.5i Limited, Ice Silver/Black
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2,116 Posts
I would try some MAF and TB cleaning. Couldn't hurt, might help.
Ignore as needed.
 

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Registered
2005 18psi supercharged U5 Outback w/207k+ miles
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757 Posts
Leak is what I thought but I did have the injectors tested when they were cleaned and they passed the tests!
 

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Premium Member
2008 JDM Outback 3.0R, 5EAT
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410 Posts
Discussion Starter #15 (Edited)
Using this fuel pressure gauge found that my fuel delivery line has 48 psi with the engine idling. The factory service manuals states it should be 48 to 53 psi, this model has no FPR under the hood.

Hot engine : 1/2 hour after turning off the engine it's 21psi. An hour after turning off the engine its 5psi
Warm engine: 1/2 hour after turning off the engine it's 35psi. An hour after turning off the engine its 30psi
Cold engine: 1/2 hour after turning off the engine it's 40psi. An hour after turning off the engine its 36psi
 

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Premium Member
2008 JDM Outback 3.0R, 5EAT
Joined
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410 Posts
Discussion Starter #16
Strangely after the fuel system is depressurised and the engine is cold she starts nicely within a second or so. So the fuel pump seems quick to do it's job. Is this too much fuel in the cylinders caused by a injector that drips only when it gets real hot?
 

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Registered
06 OBW 2.5, 05 Forester, had 03 H6 OBW
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5,935 Posts
Strangely after the fuel system is depressurised and the engine is cold she starts nicely within a second or so. So the fuel pump seems quick to do it's job. Is this too much fuel in the cylinders caused by a injector that drips only when it gets real hot?
If too much gas, crank with pedal floored, if it starts right up it was flooded.

I think if just one injector leaks the entire intake gets a too-rich mixture, it doesn't stay confined to one cylinder (unless maybe that intake valve happened to be open)
 

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Premium Member
2008 JDM Outback 3.0R, 5EAT
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410 Posts
Discussion Starter #19
If too much gas, crank with pedal floored, if it starts right up it was flooded. I think if just one injector leaks the entire intake gets a too-rich mixture, it doesn't stay confined to one cylinder (unless maybe that intake valve happened to be open)
Thanks for the tip, it starts good with the accelerator pedal down. I'll test a couple more times tomorrow but seemed to start much happier this way today.
 

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Premium Member
2008 JDM Outback 3.0R, 5EAT
Joined
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410 Posts
Discussion Starter #20
I think if just one injector leaks the entire intake gets a too-rich mixture, it doesn't stay confined to one cylinder (unless maybe that intake valve happened to be open)
Could you pressurize the fuel system and clamp off one side of the engine and test the other?
I clamped off the fuel feed to the rails individually and watched the pressure gauge drop to almost zero in both cases with a hot engine. This is a return less system I don't know what effect that has. Also had the injectors tested again by another company who found no problems with flows, resistance or leak down.

I would try some MAF and TB cleaning. Couldn't hurt, might help.Ignore as needed.
The MAF sensor is new OEM and checked the TB was clean. I temporarily switched back to the old MAF with no luck. Checked the injector bodies using a good flash light which shows no external leakage after spirited driving all six look dry aside from one that has a barely noticeably very slight sheen.

Noticed the fuel trims at idle were -5% bank 1, -10% bank 2. Checking records pre-problem the trims were a little negative on bank 2 but always inside +-5% both sides. This weekend I switched injectors across banks and the trims didn't follow (after ECU reset, 15 minutes learning idle and an hours drive).

The car intermittently smokes from both exhausts at idle even when the engine is at full temperature and heat soaking for example in heavy traffic or at traffic lights.

Now I'm stuck for ideas, the long cranking still happens and really appreciate the advice here.
 
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