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Guest Message by DevFuse
 

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fuel starvation when accelerating


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13 replies to this topic

#1 sidekickin

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Posted 07 January 2004 - 02:06 AM

I have still not uncovered the source of my problem yet, but I have noticed that it ALWAYS happens when the car has less than a half tank in it. From FULL down to a half, it almost never has the fuel starvation symptoms. But after it gets below a half tank it starts doing it. I can drive over 100 miles on the last half tank of gas, so it obviously has gas in it and the gauge is working properly. Just wanted to add that in case that is a tell-tale symptom of a problem. Is there anything that can cause these symptoms when there is less than a half tank in the car? Any other possibilities? Original message is below. Thanks for any input.



ORIGINAL MESSAGE:

Hey guys,
Got another problem that I am hoping you can help me with. This one just developed a few days ago. Occasionally when the car is accelerating or under a load (going up a hill), the engine will start sputtering and running rough....like it is not getting fuel or the car has run out of gas. It will do this intermittently from time to time. When it does this it will do it for 5-10 seconds and be done. Otherwise this car runs perfectly. It idles perfect and performs perfectly. But it only does this when it is under a load. When it is doing this and I floor the pedal to kick in the 2-barrel, it runs fine and takes off. So I don't think it is the fuel pump or the fuel filter. Because if either of those 2 were bad, the problem would be aggravated when kicking in the 2 barrel and needing more fuel. It typically does this at a higher RPM range also, like when you are winding out the gears when accelerating. At lower RPMs it does not have a problem. It acts as if it is starving for gas....not like it is misfiring or anything. It has steadily gotten worse over the past week. Fuel filter has been replaced, along with dist cap, rotor, plugs, wires, and a new catalytic converter about a year ago. Car has a Hitachi 2BBL carburetor. Could this be a symptom of a carburetor problem or something else? Any help is greatly appreciated! Thanks.

Bill

______
1987 Subaru STD 4WD Hatchback
EA-81 w/hydraulic lifters
Hitachi 2BBL carb
Single range 4WD
133,000 miles

#2 edrach

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Posted 07 January 2004 - 02:32 AM

Not sure this can happen on a Subaru but I've had it happen with an older VW Beetle. There is a vent on the gas tank to equalize pressure as the gas is drawn out. If the vent clogs or the vent line is kinked, a vacuum is built up in the tank and the fuel pump can no longer overcome that and the car seems to run out of gas or exhibit fuel starvation symptoms. Next time it happens, stop and pull the gas cap to equalize pressure. If the car is okay again for a while, start looking to clear the vent line.

#3 sidekickin

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Posted 07 January 2004 - 02:43 AM

Thanks Ed. I will check into that. I appreciate it!

#4 morf

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Posted 28 December 2011 - 07:18 PM

I have the same exact problems as you on my 87 GL. Not sure what kind of carb it has. The car is a lot worse when below half a tank like you said and it can barely get up steep hills when cold. I'm about to change the fuel pump but was hoping some one had more knowledge on this.

I already have an aftermarket fuel pump from autozone; was only $30 after using the $20 credit I had. It says in the instructions to wire it to the oil pressure switch but I'm not sure if this car has one or where it is. Can I not just wire it to the original wires?

I think it may also be a vacuum leak but it looks like the EGR system has been removed by a previous owner and I can't find a very good diagram.

Also the car has exhaust leaks.

When it's warm out and has a full tank of gas it drives awesome and is so fun.

Any help would be very much appreciated as I am working on a budget and really have no clue where to start.

#5 sidekickin

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Posted 28 December 2011 - 08:50 PM

My problem ended up being a clogged fuel filter. I replaced both the fuel filter that is under the car and the vapor separator "filter" that's under the hood. After doing that I haven't had any problems since. Your problem sounds exactly like mine. It was worse when going up steep hills when cold and when it had less than a half tank of gas. The filters aren't expensive either. Hopefully that will solve your problem.

#6 morf

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Posted 28 December 2011 - 10:37 PM

I was told the previous owner had changed the fuel filter; however after looking at the fuel pump it looked like that one down there had never been changed. Hopefully I can just change that one and return the fuel pump. Can you tell me more where both are located so I can see if they have been changed? I'm sure I can find them it's just the parts in this car are a bit different than others I have worked on.

Thank you for your input! I will let you know how it goes tomorrow afternoon.

#7 sidekickin

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Posted 29 December 2011 - 01:55 AM

On my car (87 hatchback), the fuel filter is under the car on the passenger side in front of the gas tank. It is mounted on top of a metal plate. It's kinda hard to see unless you are looking closely for it. As far as the vapor separator goes, it is mounted in the engine compartment on the driver's side, right above the brake booster. Not sure which GL model you have, but the GL hatchbacks of that year are mechanically different from the GL sedans and wagons. What I described is for the GL hatchback...the fuel filter locations may or may not be the same for the GL wagon/sedan. I've never owned a wagon or sedan of that year, so I don't really know. I hope this helps.

#8 morf

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Posted 29 December 2011 - 02:32 AM

Mine is also a hatchback! It's so weird responding to a post of over 7 years and getting useful info from the original poster.

Tomorrow afternoon I will be taking of that metal plate that houses the square fuel pump and fuel filter. I will also look at the Vapor separator that you talk of. I have looked at the fuel pump already and it looks like it has never been touched and the steel plate housing it has probably never came off before.

#9 sidekickin

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Posted 29 December 2011 - 08:11 PM

If you can't get the plate off, you can remove the fuel filter with it in place. It's not convenient, but it can be done. That's how I had to do it since all the mounting hardware for that plate was rusted in place. After replacing that filter and the vapor separator, I haven't had the problem ever come back...and it has been almost 8 years now. Unfortunately, someone just rear-ended the car a few weeks ago and it looks like it will be totaled. Just waiting on the insurance adjuster to make it final. Hopefully I can find another one somewhere. It was the best car I ever owned. Let me know how everything goes...

#10 morf

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Posted 30 December 2011 - 12:04 PM

The only filter I could find was a see through white plastic one next to the pump under the car; it looked to be a year or two old. I don't see any filter at all under the hood above the brake booster. I do see the fuel lines coming out right there with a little round metal tube on one of the lines that is not much bigger in diameter than the line its self and only like 1 inch long. Perhaps my model does not have the vapor separator.

I can't look at the car till after 4pm and it get's dark shortly after so I never have time to really get into it. Will be working on this today for an hour and all day tomorrow.

If I did find this fuel vapor separator where would I find another one? Can't find it anywhere online. Do I need to go ask the dealership?

Also does anyone know about installing this aftermarket fuel pump? The instructions say to wire it to the oil pressure safety switch but why can't I just wire it to the old wires?

I kind of want to narrow this down before I start replacing parts and spending money.

Thank you so much for your help sidekickin. Will keep you updated.

#11 morf

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Posted 30 December 2011 - 06:52 PM

Tomorrow I'm going to replace the fuel filter next to the fuel pump. The filter its self did not look that old but I could see a lot of gunk on the inside of it. I think I might also replace the pump with the aftermarket one I got from auto zone. It came with a different kind of filter though.

Maybe my car doesn't have the fuel vapor separator because it has the EA82 engine? Also when I went to find the fuel pump fuse it was already disconnected so the fuel pump must have already been rewired by some one else.

I'm getting no where fast with this car.

#12 sidekickin

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Posted 30 December 2011 - 11:25 PM

I have the EA81 engine...not sure if the EA82s have a vapor separator.

#13 morf

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Posted 02 January 2012 - 08:48 PM

Replaced the fuel filter and it runs much better! Still slows a little on really big hills but keeps speed. Thank you very much sidekckin! My hatchback does not have a fuel separator.

Just need to figure out why the choke does not work correctly when I first start it and with the heat/AC on.

#14 peterelliott05

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Posted 06 June 2014 - 02:06 PM

Hey Guys,

 

My 1983 Subaru GL Wagon is having this same issue. I replaced the rear fuel filter, the front fuel filter, but it has not solved the problem. Did you guys come up with any other solutions for fixing this problem?

 

Thanks!






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