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2001 Outback base
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Discussion Starter #1
CEL came on during last drive on highway. While arriving home I began noticing a raw gas smell coming in from vents. I suspected that I had another loose clamp on a fuel line (as was the culprit earlier this fall when the weather turned colder and I had a gas smell in the interior) and indeed I did. The clamps were a bit tough to get to this time, but I was able to fix the leak. Is it possible that the fuel leak was responsible for the CEL coming on? The codes suggest a lean mix (P0171 and P0174) and so it seems logical to me. If not, any suggestions about things to worry about? I checked the PCV and it seems to function well. Otherwise all seems normal.
 

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Master Caster
2005 XT, Mildly Modified...2006 XT Limited, Highly Modifed
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Yep,

I would guess the lean code came from lack of proper fuel in the intake charge.
 

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'14 Subi OBW, '18 Subi Forester
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Not a year went by from 2001 thru 2016 that I didn't have to tighten a clamp or two an eighth to a quarter turn on the first sub-zero day with that car! I even drilled some holes on the shield near the passenger side front cylinder to get the best angle on those two clamps under the corner cover.

However, I'm a bit dubious that there is a direct connection between the two events. In order to get a lean mixture CEL, you'd have to experience a substantial pressure loss in the lines. That might be true of a truly wiggly hose clamp or a pinhole spraying fuel, but not from the tiny, barely visible seepage typical of the hose clamp connections of the Gen-II engines on a cold winter day. It doesn't take even a half teaspoon of fuel on hot surfaces to flood the cabin with that stench.
 
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Master Caster
2005 XT, Mildly Modified...2006 XT Limited, Highly Modifed
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However, I'm a bit dubious that there is a direct connection between the two events. In order to get a lean mixture CEL, you'd have to experience a substantial pressure loss in the lines.
I think this depends on many things. Fuel pump duty cycle, engine load , timing, ecu reaction.
 

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Discussion Starter #5
Both clamps were a few turns loose (and one of them was tough to get to as it was under a metal cover—the clamp was loose enough that I was able to rotate it so that I could get a bit into it to tighten it). The gas was actually dripping at idle. I’m not sure if it would leak worse at higher rpms but I assume so. And then the light came on when I was traveling at a high speed and so it’s possible that there was low pressure in the fuel system if the line was leaking heavily. A lot of assumptions go into this and so I understand that the likelihood of the loose clamps being the culprit is low.

I’ll see if the light goes out over the next few days. Otherwise I’ll bring the car in to a mechanic to evaluate other potential causes of the lean mix. Thanks traildogck and Fibber2 for your insight!
 

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On the Super Mod Squad
2002 3.0 VDC Wag + 2018 2.5 Leg Ltd
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Both clamps were a few turns loose (and one of them was tough to get to as it was under a metal cover—the clamp was loose enough that I was able to rotate it so that I could get a bit into it to tighten it). The gas was actually dripping at idle. I’m not sure if it would leak worse at higher rpms but I assume so. And then the light came on when I was traveling at a high speed and so it’s possible that there was low pressure in the fuel system if the line was leaking heavily. A lot of assumptions go into this and so I understand that the likelihood of the loose clamps being the culprit is low.

I’ll see if the light goes out over the next few days. Otherwise I’ll bring the car in to a mechanic to evaluate other potential causes of the lean mix. Thanks traildogck and Fibber2 for your insight!

this is kind of a regular cold weather thing in a couple places around the 2000-2004 H4 engines.

I tried with screw drivers on those clamps around the engine and could not find any loose.


on my own 2002 H4 it needed a 4" length of rubber fuel line in the area at that metal cover on the passenger side front of the engine. did not cause a check engine light,

but when down by 20 F when the car was just stopped idling or just shut down it would stink into the cabin. I guess when the car was moving the air was sucking all the stink away from the vents.

to look for it though you had to be quick as the drops would dissipate fast. I had to tell the mechanic that I left it at where to inspect by pointing. and that he had to leave it outside and find it when the temps were down by 20F. any warmer and no leak at all.
 

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I suppose if your fuel pump is really marginal, the pressure regulator isn't doing it's job or the injectors are pretty clogged, any leakage might be enough to push it over the edge. But on a healthy system, some minor loss shouldn't trigger CELs. I guess we'll see what happens.
 

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Discussion Starter #8
I’ve had a lot of loose clamps and this is the second leak with raw gas smell this fall (both leaks came from different short runs of rubber fuel lines—first one on driver’s side and easy to get to and then the second on passenger’s side under the cover). And yes, both happened after a drop in temperatures and when this recently happened, I think it was in the teens.

I suppose it’s a good idea to replace the rubber lines and clamps and that this would prevent leaks from happening again. It looks like the rubber fuel line and clamps can be easily replaced for the line on the driver’s side, but how difficult is it to do the other one that’s under the cover on the passenger side? Does the cover come off easily? I see one bolt on the top of the cover and then it looks like two more on the bottom attachment. a/c lines are also attached to the cover and in the way if trying to remove the cover (I see how the lines can be disconnected from the cover, but they’re not going to budge too much to get them out of the way). Seems possible, just not so easy. And should I expect to have a lot of gas flow when the lines come off?
 

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On the Super Mod Squad
2002 3.0 VDC Wag + 2018 2.5 Leg Ltd
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on mine that little cover has a couple factory welds to hold it in place. (I guess subaru does not want anything landing on that bit of fuel line).

I dropped it at a mechanic with a hot garage and he swapped the line with some other work the car needed at the time.

I would think you can get at the clamps with 90 degree tools like screw drivers and needle nose pliers.

if you want to draw all the pressure out fo the fuel lines pull the fuel pump fuse and try to start.

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that was the one and only fuel line I had replaced on either of my 2002 cars due to a leak. so maybe something to put on a maint. to do list for the spring and summer if you don't have a warm garage to work in today.

maybe over the years the rubber lines by the under the hood filter canister got swapped out too with a canister.
those canisters have flutes on the tips, and the rubber lines shrink to them after 12 years,... not much debris can get get in them as subaru puts a filter in at the pump in the tank.
 

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For reasons I don't remember, there was actually a recall on WRX models of the same period in which SOA provided a kit with some new lines (change of materials, longer, IIRC) and a revised clamp. But only on the turbo motors. On all the rest, and I remember a lot of coworker complaints about this, we just went out and tightened them up.

I bought a kit of right angle ratchet drivers, but still had difficulty getting a P2 bit on the heads. I finally realized that my problems around the cover were likely related to the leaking head gasket job that my selling dealer had to do (for the first of two events) at a mere 15k miles. When they reassembled things, they rotated those **** clamps out of alignment with the holes in the cover. Eventually I drilled supplemental holes so that I could obtain proper alignment once again.
 

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Discussion Starter #11
CEL still on after several drives over the past days for just over 240 miles. Despite no obvious differences in how it runs, I guess there’s an issue that needs to be addressed.
 

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Depending on the issue, codes and dash lights have different clearance periods. If you want to know for sure, you really need to clear it and see if it returns. I strongly suggest that you do this with a scan tool and not just with a battery disconnect, as that clears/impacts so many other learned values.

If it does return, capturing the freezeframe data that accompanies the code would be very useful. The stored data might help pinpoint the conditions that lead to failure.
 

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Discussion Starter #13
Thanks for the advice Fibber2. Will plan accordingly, but not likely to do much more driving or get these things accomplished till the new year.
 

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2001 OBW Base H-4 2.5L Auto
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Glad i came across this as the last few days i have noticed a fuel smell in the cabin of my 01 and thought it was my remote start over priming /cranking. I'll have a look at the clamps as its been in the single digits here for a bit.
 

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Discussion Starter #15
i Was ecstatic to finally see the CEL go off today (after at least six 50 mile round trips and a few other local drives). Nonetheless, it came on again on the way home...

I assume this means that it is highly unlikely that the CEL and codes indicating a lean mix were due to the gas leak last month. I have an appointment with a mechanic soon — hopefully he will be able to diagnose this issue more completely.
 

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Not a year went by from 2001 thru 2016 that I didn't have to tighten a clamp or two an eighth to a quarter turn on the first sub-zero day with that car!
I had to tighten the clamps twice this winter already. Its in the 60s today after prolonged temps in single digits and teens. I fully expect to tighten them again this weekend when we return to sub freezing temps.
 

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Discussion Starter #17 (Edited)
Light is off again...

Aside from fluctuations in weather (cold then warm then cold temps) and new tank of gas recently, I can’t think of anything else that has changed.

I assume that the issue associated with the light coming on is intermittent and the irregularity of this will make it more difficult to diagnose the actual problem. Will the codes associated with the last time the CEL came on (second time) still be in memory for when I have my mechanic check it out next week?
 

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The retention of codes question is tough to call. Some remain forever, so things that you'd think would remain stored get wiped. It seems to depend on situation, severity, year, etc.

Have you tried a can or two of Seafoam, CRC Guaranteed to Pass, Techron or some other fuel system cleaner to go after deposits in injectors or on valves? Rarely will it hurt, and often it can help. At worst, you'll be out the value of a few overpriced coffee house visits.
 

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Discussion Starter #19
Will see if the codes are retained... No, I haven’t tried any of the additives. The car seems to run perfect with no knocks or hesitation or other issues. I’ll wait to see what the mechanic concludes.

I did though have gas leak issues again this morning (another big drop in temps today). It was the same difficult to get to fuel line. It looks like I have the clamps tight again (and even tightened a few others that were a tad loose but not leaking yet), but this is frustrating. I think that when I bring the car in to get checked out next week I will have the mechanic change out all lines and clamps so this issue goes away.
 

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2005 Outback R LL Bean 3.0 H6 w/ 5 speed sport shift
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Are the leaking fuel lines specific to only the H4's of a certain generation or do the H6's in Gen 3 have this problem too?
 
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