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82 EA-81 fuel delivery problem


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17 replies to this topic

#1 IASUBE

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Posted 02 November 2009 - 11:19 AM

Just picked up a "NEW" 3-eyed Wagon for $50.00 from the original owner dual range 4 speed with 123,000 miles on it...:banana:
Trying to sort out a fuel delivery problem (main reason the origanal owner gave up on it).. Car will start and idle fine, and slow speed moving around the yard is fine... driving down the road a load in second or third gear the thing just runs out of fuel and lays down, let off the gas a it will come back to running.
History that I know, it has new fuel filters on it, a non-stock replacement fuel pump, and this one has the Carter-Weber 1 bl Carb.
So yesterday I ran a little test... I rigged a 1 gallon fuel tank and the old fuel pump (found it in the back of the car) under the hood and hooked it up to the feed line to the carb and plugged the one from the tank.. The mighty EA-81 pulled smooth to 6000 rpm in second and third gear...
So the question is, Has anyone had problems with the fuel pick-up in the gas tank, or the hard lines in the system? I will be replacing all the rubber lines tonight, just wondering where elce to look...
Thanks for any ideas of where to look... IASUBE

#2 GeneralDisorder

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Posted 02 November 2009 - 01:23 PM

Yeah - blow out the hard lines with compressed air. The tank may need to be replaced if all the filters are clear.

I would check that the rear fuel filter isn't clogged (again) due to excessive deposits flaking out of the tank.

You can try blowing back through the pickup line to see if that dislodges anything. Remove the sending unit if you dare to see if there is a lot of debris in the tank.

GD

#3 bheinen74

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Posted 02 November 2009 - 01:26 PM

cool another local.

#4 VaporTrail

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Posted 02 November 2009 - 02:00 PM

Just picked up a "NEW" 3-eyed Wagon for $50.00 from the original owner dual range 4 speed with 123,000 miles on it...:banana:
Trying to sort out a fuel delivery problem (main reason the origanal owner gave up on it).. Car will start and idle fine, and slow speed moving around the yard is fine... driving down the road a load in second or third gear the thing just runs out of fuel and lays down, let off the gas a it will come back to running.
History that I know, it has new fuel filters on it, a non-stock replacement fuel pump, and this one has the Carter-Weber 1 bl Carb.
So yesterday I ran a little test... I rigged a 1 gallon fuel tank and the old fuel pump (found it in the back of the car) under the hood and hooked it up to the feed line to the carb and plugged the one from the tank.. The mighty EA-81 pulled smooth to 6000 rpm in second and third gear...
So the question is, Has anyone had problems with the fuel pick-up in the gas tank, or the hard lines in the system? I will be replacing all the rubber lines tonight, just wondering where elce to look...
Thanks for any ideas of where to look... IASUBE


Welcome back! only 25 months since your last post :lol: i'd run a bunch of seafoam through the tank, and see if that helps at ll, and change both fuel filters again... you may need to find a radiator shop to boil out the tank....

#5 IASUBE

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Posted 02 November 2009 - 02:19 PM

GD, thanks I had thought about blowing out the hard lines, wasn't sure about blowing back into the tank, but will give that a shot tonight too...
along with checking the rear filter..... will keep my fingers crossed the tank won't need replacing... as the older wagons are getting harder to come by. Do you happen to know what the fuel test pressure should be for a Carb. system? my book only list pressure for Fuel Injection models.
Going to change the rubber lines and try the original pump tonight (as it seemed to work fine) using the 1-gal antifreeze... I mean gas tank, yesterday. I guess a pinched hard line could restrict enough fuel to cause the problem.... but don't they run through the cabin?
IASUBE

#6 GeneralDisorder

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Posted 02 November 2009 - 02:26 PM

The carb fuel pressure should be around 1.5 to 2.5 psig. That's off the top of my head but it's close. It will be hard to test that small of a pressure unless you have a gauge specifically for it like a 0 to 5 psi gauge.

Pressure *may* not tell you much though unless you test it while driving - the problem is most likely a volume issue and not a pressure issue. It can build enough pressure to keep the float bowl filled while idleing and driving slow, but it can't keep up with the volume requirement at higher RPM/Load. You would see a pressure drop if you drove it with the gauge installed but likely a static test won't show you much. Although it would be a good idea to check that "new" pump for proper pressure or just put the old one back in. They rarely fail.

Oh - and when you are blowing stuff out - regulate your pressure down to maybe 25 psi or so. You might damage something that's close to rusting out if you put too much pressure to it.

GD

#7 bheinen74

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Posted 02 November 2009 - 02:41 PM

fuel pressure on ea81 non fuel injected 1.5 to 2.5 psi as mentioned.

#8 IASUBE

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Posted 02 November 2009 - 03:30 PM

Thanks for the reply's, I do have a low pressure gage I could test the pump with, but would have to tee it in and drive it, as GD mentioned it's a volume problem, as it will sit and idle for ever, but I think I'll blow out the lines and put new rubber on and test it tonight...if I need filters I'll have to order them I'm pretty sure.
I'll be sure to keep the pressure down when I blow out the lines as bheinen74 and McBrat know the midwest is the Rust-Belt. The fuel from the tank smells ok... but I don't know how long this wagon's been sitting, but will consider the sea foam.
Dang Mick, Can't an Iowegian get a break? I've been here the whole time... averaging 1.5 post a year for the last six years :lol:...
IASUBE

#9 IASUBE

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Posted 03 November 2009 - 08:43 AM

Update: Installed new rubber lines and the old original fuel pump last night after blowing out the hard lines, the line running forward to the engine blew out with no noticeable restriction, hard to tell with gas in the fuel tank, if there was a restriction going that way... Anyway, hooked everything up and cranked the starter till I had a good flow out the line going to the carb purging the whole system... The short test drive of 2 miles or so (no tags on it yet) went well, it run good and pulled clean thru all the gears.
Best guess is the screen or sock in the tank was close to plugged? I'll get tags and ins. on it this week, so I can try an extended drive, if the problem returns I guess I'll be pulling the tank for a cleaning. thanks for the replys... might have rescued another wagon! :banana:IASUBE

#10 Yo'J

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Posted 03 November 2009 - 11:31 PM

SCORE!:banana::banana:

#11 Greenley

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Posted 04 November 2009 - 07:36 PM

Keep us posted if it the problem does in fact return, please :)

#12 IASUBE

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Posted 13 November 2009 - 11:19 AM

OK after blowing out the hard lines and installing old pump... the car ran great for a while, drove it to work and back (25 miles round trip) all week, till this morning on the the way to work it started it again, wouldn't pull past 45 mph in 4th gear... same thing it would run out of gas and start a lean miss-fire untill you let off the gas.. took it back home and drove the truck to work. The fuel tank will be comming out after work today, as this is my best guess as to where the real problem is, I will have the camera handy in case there's something in there that needs to be seen. I won't be back around a computer till monday... I'll report back with my findings then... IASUBE

#13 GeneralDisorder

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Posted 13 November 2009 - 12:10 PM

Pull the sending unit and take a look inside. You may be able to do a partial clean through the sending unit hole on the back of the tank. There is also a drain plug on the bottom of the tank - that will help.

GD

#14 IASUBE

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Posted 13 November 2009 - 01:14 PM

Thanks GD, I will start with the sending unit first and go from there, I think I'll grab a couple of large coffee filters here at work so I can see if there's anything in the gas when I drain it... And thank-you Subaru for having the forsight to install a drain plug in the gas tank... not many makes do.
IASUBE

#15 hatchsub

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Posted 13 November 2009 - 02:04 PM

T And thank-you Subaru for having the forsight to install a drain plug in the gas tank... not many makes do.
IASUBE


Yea i would have loved it if my camaro had a drain plug on the tank. It wouldnt have cost much to do..and make the work so much easier. I had to lift about 7 gallons of gas in the tank when i dropped it to replace the pump....So to make a long story short:

Subarus are super easy to work on compared to other makes.

#16 IASUBE

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Posted 16 November 2009 - 10:35 AM

Started out with draining the gas tank saturday morning... found next to nothing in the funnel filter after ~7 gals. were drained, pulled the sending unit (thanks GD) and rigged up a small marker light bulb on a coat hanger wire for a look inside. The tank looked really clean inside, and I could not see any blockage in the ~3 inch tall nylon-mesh screen inlet pickup in the tank... watched while a friend blew back thru the line with air... nothing. So I buttoned it back up and T'd a low pressure gage into the line going to the carb from the front filter, taped the gage to the w/wiper arm and went for a test drive.

The stock Subaru pump would run about ~.75-1.25 psi at idle and drop off to zero under load in 2-3rd gear, you could get ~.5 psi higher idle reading pinching off the upper (return) hose on the front filter, but pressure would still drop to zero under load with the lean missfire/power drop-off shortly afterwards (as the float bowl ran empty).

A good friend happened to have a new in the box "Holley Red" pump lying around... so we cobbled it in there for a test, paper work in the box said the pressure is preset at 7 psi. At idle the pressure was around 2.5-3.5 psi.... on the test drive, trying to load it down good, I could get it as low as ~1.5 psi. on a 1500-6000 rpm pull at wot in third gear... at cruise it would hold a steady 2.25 psi.

So the holley pump got tied up under the car a little better and will drive it this week as a longer term test, while I'm deciding what to replace it with... as the red pump is a little too big to fit nicely under there.

Car seems to run great, idle rpm may have increased a bit, I will check the calibration or the gage I used in the test, against a HEISE CMM I have here at work... as the indicated pressures seemed a bit low... never the less... I beleive the cause of the problem was confirmed..
IASUBE

#17 GeneralDisorder

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Posted 16 November 2009 - 10:51 AM

Sounds like the old pump is just tired. Glad you figured out the problem and your tank isn't a rust ball - that would be a much worse problem to have to deal with.

GD

#18 NV Zeno

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Posted 16 November 2009 - 04:41 PM

:popcorn:.

Please keep us posted on your research and results.

Edited by NV Zeno, 16 November 2009 - 04:42 PM.
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