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Fuel pump? Leaky o-ring? Other?


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34 replies to this topic

#1 Jimbo67

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Posted 20 June 2012 - 12:46 AM

A few months ago I bought a 2000 Outback (4 cylinder) with 70k from a friend's parents. They work out of the country and drove it infrequently, but are the type to stay on top of scheduled maintenance.

I drove about 2000 trouble-free miles including some longer road-trips. Then, a few days ago I went on a road-trip and when I arrived in Vegas (hot, middle of day -- not sure if this is a factor) the engine started cutting out on the freeway. Seemed to be worse under load (hill) and the power really cut-out as I was starting through an intersection and I coasted to the side of the road. No warning lights flashed on the dash (and haven't any other time). I restarted it a few minutes later and it drove great.

The next day the auto parts guy suggested a new fuel filter, which I put in. I drove about 200 miles through Death Valley (110+ degrees) with no problems, but then on a hill it started cutting out again, and got bad enough that I had to pull over. After letting it sit off for a few minutes, it was difficult to start, but ran fairly well (not perfectly) for the next 40 miles or so.

I checked it into a repair shop in Lone Pine CA and they were able to get it to cut out, but said the computer did not indicate any problems, and the history didn't either. Said it could be one of a dozen things (fuel pump, lose wire to fuel pump, etc, etc, etc), and that they could throw parts at it but it could cost $2k to hit the right part.

I picked-up the car, filled it up and drove about 200 trouble-free miles back through Death Valley (115+ degrees), but just outside of Vegas it started acting-up. As usual, it started with a very slight cut in power, and I could induce a full-blown series of power cuts by pushing on the accelerator hard. I'd noticed that the problem seemed to happen when fuel was below a 1/2 tank, so I stopped and filled up and the problem went away and I drove another 20 miles to Vegas.

Subaru service person in Vegas said it might be a fuel pump, and that she'd once seen one with a problem that was related to fuel level, but that it was not the norm. Called Subaru service guy in Salt Lake and he floated the idea of a dirty tank or a crack on the fuel assembly that sucked air below a certain fuel level.

I drove north toward St. George and about 100 miles later I was going up a grade and the symptoms returned. Got so bad I had to pull over and stop. Started up again after a few minutes and it ran great for about 15 miles but then returned and I barely limped off the freeway and made it to a gas pump. Put in 6 gallons and it ran perfectly for another 80 miles where I stopped for the night.

After hours of thinking about it, a lot of Google searches, and talking with some friends, I'm thinking it could be the fuel pump, or possibly a bad o-ring/seal or crack in the fuel assembly that is letting in air when the fuel drops to a certain level.

Thoughts? Opinions?

Edited by Jimbo67, 20 June 2012 - 12:48 AM.
misspelling


#2 Fairtax4me

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Posted 20 June 2012 - 01:06 AM

Read the info about the fuel pump assembly in this thread: http://ultimatesubar...ad.php?t=133579
I don't know for sure which years this issue affects, but it seems to be fairly common, and it's easy to check.

#3 grossgary

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Posted 20 June 2012 - 04:36 AM

i would keep driving it as-is and refilling the gas every 50-100 miles just to be sure it never happens again.

at this point i wonder if the gas-station fill ups are just a time for it to cool down and set rather than the actual cause. correlation does not mean causation.

the timing belt is due on that car and if it breaks it will have bent valves and major engine damage. if it hasn't been done it's due....by 3 years or more.

you could install or have a fuel pressure gauge handy and check pressure next time it has issues running/starting. this will verify if you have proper fuel pressure to the engine.

#4 porcupine73

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Posted 20 June 2012 - 07:44 AM

What is the fuel pump issue, if the suction strainer falls off into the tank?

Hm anyone think the knock sensor could cause this type of issue? They don't always throw a code but the ECU might think it is knocking. I had one that was flaky, though it did throw a code, but you would be driving, it would suddenly just go absolutely gutless and acting like it was going to stall, then the CEL would come on with knock sensor code?

#5 Jimbo67

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Posted 20 June 2012 - 09:16 AM

Thanks for the replies --

Fairtax4me: Thanks for the link!

Grossgary: You confirmed the same thought I had about checking it with frequent fill-ups. I'm going to drive home 300 miles to Salt Lake tonight and will do this. I agree that correlation is not necessarily causation. Thanks for the heads-up on the timing belt -- I was only thinking in terms of miles. I'm headed to the parts store to see about the fuel pressure gauge, just not sure the problem will stay happening long enough for me to get a gauge on it.

Porcupine73: Depending on my test drive with a relatively full tank, I'm going to pull out the fuel assembly and see if there are any obvious issues. I don't know enough about knock sensors to have an opinion on this.

Thanks!
Jim

#6 grossgary

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Posted 20 June 2012 - 09:29 AM

I'm headed to the parts store to see about the fuel pressure gauge, just not sure the problem will stay happening long enough for me to get a gauge on it

what would be nice is to install a fuel pressure gauge that you can leave in place - like with a T fitting or something...heck even with the gauge ran to the cabin if you're having really strange symptoms/problems.

in my experience Subaru fuel issues are very rare so i'm hesitant to be confident this is the fuel pump.

#7 Scarpachy

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Posted 20 June 2012 - 05:54 PM

We have fixed two Outbacks in the past month with similiar issues. Both cars were losing fuel pressure, and causing lack of performance. Or causing hard starts. Allowing the fuel pressure to bleed off. If you pull your fuel pump assembly out of the tank. There is an acummulator built into the main assembly. It has a large round metal cap with three tangs to secure it when tightened down. It uses a large o-ring to seal that portion. And both of the two we had, were deformed. The cap came partial detatched, and the large o-ring gets sort of sucked out and loses it's ability to hold pressure. You can either buy a new main sender unit. Or if possible you can twist the cap off, and reinstall it, if the o-ring is not damaged, and the securing tabs can be bent back in a way that it will stay secured. This may not be the problem, but it is fairly easy and a quick thing to check in about 15 minutes or less. And something that may get over looked by a shop that may just think the fuel pump is failing. Which does happen as well.

Good luck.

#8 grossgary

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Posted 20 June 2012 - 10:50 PM

We have fixed two Outbacks in the past month with similiar issues. Both cars were losing fuel pressure, and causing lack of performance. Or causing hard starts. Allowing the fuel pressure to bleed off. If you pull your fuel pump assembly out of the tank. There is an acummulator built into the main assembly. It has a large round metal cap with three tangs to secure it when tightened down. It uses a large o-ring to seal that portion. And both of the two we had, were deformed. The cap came partial detatched, and the large o-ring gets sort of sucked out and loses it's ability to hold pressure. You can either buy a new main sender unit. Or if possible you can twist the cap off, and reinstall it, if the o-ring is not damaged, and the securing tabs can be bent back in a way that it will stay secured. This may not be the problem, but it is fairly easy and a quick thing to check in about 15 minutes or less. And something that may get over looked by a shop that may just think the fuel pump is failing. Which does happen as well.

Good luck.



i have a thread with some information about this issue. i got orings at Advance Auto Parts that work.

i tried to reuse my cap, it lasted about 200 miles even with a new oring. i got a new cap for it and it was all good, with another new oring. even the new oring was blown out of shape, i presume by all the fuel and pressure *pushing* it out the gap?

i have a picture of the metal caps in the parts wanted forum and part numbers posted in another thread for the orings at Advance Auto Parts.

#9 Jimbo67

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Posted 20 June 2012 - 11:57 PM

Scarpachy and Grossgary -- Thanks! You both confirmed the course of action I've been thinking of taking, and hoping that a cheap (not counting the $160 I've spent so far) o-ring might be the problem.

Drove home today with zero cutting out. Filled the tank at 80 miles, then at about 100, then decided to see if pulling over and stopping at 90 miles with the gas cap off would simulate a gas stop without putting gas in. Drove another 60, for a total of 150, with no engine problems. Not sure what this means, if anything.

I watched a video on pulling the fuel assembly and it looks easy. It's certainly worth a try.

Thanks!
Jim

#10 grossgary

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Posted 21 June 2012 - 05:55 AM

I watched a video on pulling the fuel assembly and it looks easy.

easy.

two 12mm bolts for lower rear seat cushion
4 phillips head screws
10 8mm bolts
two hoses and an electrical connector

and on my 2003, even in the rust belt, were rust free!

#11 cohophysh

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Posted 21 June 2012 - 10:51 AM

I am having the same issue with my 90 2.2 with 363k miles...wonder if it is the fuel pump...hmmm

#12 porcupine73

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Posted 21 June 2012 - 11:03 AM

Hm well with that many miles, it is possible!

Yes the fuel pump area does seem to be rust free even on my old rust bucket soobs. Now if we could just keep the brake lines, filler neck, and the 4038 little metal emissions tubes under there in the same condition we would be home free!

#13 cohophysh

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Posted 21 June 2012 - 11:45 AM

this is beginning to be just stupid, the spark plug wire keeps popping off of the spark plug causing the car to run rough. I push them all the way in until I feel it click...time for new wires...

#14 Jimbo67

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Posted 21 June 2012 - 06:25 PM

Scarpachy or Grossgary - Any thoughts on where to buy these parts? I realize Grossgary mentioned Advance Auto Parts for the o-ring, not sure if you also bought the cap there. We don't have a location in Salt Lake, but I can order them.

I called the local dealer and they want $65 for the cap and $39 for the o-ring (I think he mentioned there were two? It got a little confusing when he started talking about o-rings for the fuel filter, which I think later car models have in this reservoir?).

Called a number of industrial and auto parts houses but had no luck finding a fuel-rated o-ring in that size. Have some leads for other sources, but it's too late to call them now.

Jim

#15 grossgary

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Posted 21 June 2012 - 09:06 PM

Scarpachy or Grossgary - Any thoughts on where to buy these parts? I realize Grossgary mentioned Advance Auto Parts for the o-ring, not sure if you also bought the cap there. We don't have a location in Salt Lake, but I can order them.


not the cap, i was told the dealer doesn't sell the cap you have to buy the entire fuel pump assembly to get it. so i got a used cap thanks to a kind forum member.

if you find they do sell the cap, please post the part number.

i posted the part number for the oring in another thread, i'm sure you could look it up online and find the dimensions to get at another store or simply match it up in another store.

the oring i bought seemed maybe a hair thinner than the original but i wasn't sure if the original was even an original size so to speak since it was obviously stretched waaaay bigger than it should have been. i think now though that only happens when they blow out under all the fuel pressure and squeezing through that tight place between the cap and where it seats.

i installed a new oring under a broken cap hoping it would hold and it only lasted 200 miles. the 200 mile oring was EXACTLY like the original one that failed but was 150,000 miles and 10 years old - stretched A LOT.

a forum member sent me an original oring and cap out of a pump and the original oring looks fine, not stretched. it is a bit thicker than the oring i used.

i was even thinking maybe the thinner oring would put less strain on the cap tabs and less likely of breaking again...but that's probably a stretch. i've driven it a few weeks now with no issues including some traveling/road trips.

#16 Jimbo67

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Posted 24 June 2012 - 05:52 PM

I pulled the fuel assembly and removed the cap to look at the o-ring. It looks to be in good condition to me, but it seems somewhat oversized (diameter, as though it has been stretched out, not the thickness of the o-ring) and I'm having a h*^ll of a time getting it back together. I'm thinking I may as well buy a new o-ring and install it. The video I watched made putting the cap back on over the o-ring look incredibly easy.

Does this seem indicative of needing a new o-ring?

Thanks,
Jim

#17 Jimbo67

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Posted 24 June 2012 - 05:56 PM

grossgary - any chance you can point me to your post about o-ring part number? i've been searching to no avail -- you have a lot of posts! (and my searching skills seem deficient)

#18 grossgary

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Posted 24 June 2012 - 11:09 PM

grossgary - any chance you can point me to your post about o-ring part number? i've been searching to no avail -- you have a lot of posts! (and my searching skills seem deficient)

i'm on a dial up at the moment....so no....dimensions posted here:

http://www.ultimates...uel pump&page=2

you can search subaruoutback.org and find it, i know the part number is posted there multiple times.

#19 Scarpachy

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Posted 25 June 2012 - 05:33 PM

Looks like the large O-ring is the same on your 00 as it is on the 03-04's.
Nate Wade Subaru (800)221-4287) can order it, they are currently out of stock. Part #42025AE02A, $33.03 list price. You might double check on part number when you call. They only list it out for the 03-04.
Here is a link to a parts diagram.

Item #12 . And if you see the compatible vehicles,yours is listed.
You might even be able to call them, and a lot of times the parts bag has the dimensions listed on them. But they may need one in stock before they could give you that info.

http://opposedforces...illustration_2/

#20 grossgary

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Posted 25 June 2012 - 07:47 PM

Part #42025AE02A, $33.03 list price.

DUDE! $33 oring that's insane!

my 99 cent oring from Advance Auto parts - the packaging which I happened to have in the back seat says "64138.1"
"2-1/8 x 2-5/16"

type "advance auto parts 64138.1" in google and it comes up
http://shop.advancea...27_A|GRP2037___

here's a highly technical run down on the oring sizing and material:
http://www.subaruout...-problem-2.html

#21 Fairtax4me

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Posted 25 June 2012 - 11:57 PM

#928 Viton metric O ring.

I'd really like to see some pics of how this whole setup works. I see there were some in the SOB thread but the links are dead.
SOB :-p

#22 Jimbo67

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Posted 26 June 2012 - 05:16 PM

The $33 option from the dealer wasn't overly enticing and I couldn't find the o-ring at any of the auto parts dealers I called. This morning I went to an industrial supply house specializing in gaskets/seals/etc and the guy gave me two for free! I have not idea about part number or size since he just handed them to me.

Interestingly, my oversized/stretched old o-ring had shrunk back to about the right size during the two days it was out and exposed to air. The guy at the supply house seemed a little non-commital, but indicated it was due to age and being less than in new condition.

I installed the new o-ring and the cap closed as easily as it did on the youtube video I watched (forgot to mention that it was REALLY difficult to get the cap off in the first place). I installed the fuel assembly and went for a test drive and everything worked great. Since I work from home I don't expect to have a longer test drive in the very near future, but I'm putting this one down to faith that it is fixed.

Thanks for everyones' input!

Jim

#23 grossgary

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Posted 27 June 2012 - 12:16 AM

Interestingly, my oversized/stretched old o-ring had shrunk back to about the right size during the two days it was out and exposed to air.

odd, i'll have to see if i have any of my old stretched ones.

i saw mentioned somewhere about if the fuel filter could be putting extra pressure on this area of the fuel pump? like if the filter is clogged - could that be increasing the pressure back at the fuel pump and on that cap/oring area?

seems plausible. and since neither of mine have had the fuel filter replaced that i know of at 160,000 and 190,000 i'm going to replace them anyway.

#24 1 Lucky Texan

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Posted 27 June 2012 - 12:19 AM

what about adopting the Aussie system, bypass the underhood filter with some tubing, then install the intank filter?

#25 grossgary

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Posted 27 June 2012 - 07:43 AM

what about adopting the Aussie system, bypass the underhood filter with some tubing, then install the intank filter?

never heard or seen what that is. i'd rather do as little playing around inside the tank as possible unless there is a very compelling reason.




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