Fuel System Issue

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Gregmy123
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Fuel System Issue

Post by Gregmy123 » Sat Jun 29, 2019 2:14 pm

Hi Folks,
I hope you can help me.
Just bought 2006 Baja Sport. 53K miles
It has been sitting in a lot for many years. New battery, Spark Plugs and Oil. Added gas + 2 bottles Sea Foam.
Started up. Got CEL code P0463.
Gas gauge was staying on E.
Replaced Fuel Pump only - on passenger's side and sock/filter.
Replaced Drivers Side Secondary Fuel Level Sending Unit + new filter.
CEL went out.
Runs fine when tank is full.
Fuel gauge now works but:
When gauge drops to 3/4 tank, engine runs like crap like it is about to run out of gas, backfiring but there is plenty in tank.
It had some very old gas in it.
What do you think?
Thanks in advance for any help!
Gregmy123

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FlyByNite
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Re: Fuel System Issue

Post by FlyByNite » Sat Jun 29, 2019 8:29 pm

Fuel filter?
Image
Yep, got a matching ARE cap.
2003 226,802 miles so far.

Enjoy
FBN

Gregmy123
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Re: Fuel System Issue

Post by Gregmy123 » Mon Jul 01, 2019 5:26 pm

FlyByNite wrote:
Sat Jun 29, 2019 8:29 pm
Fuel filter?
This filter is inside of tank - part of Fuel Pump Assembly.
I replaced it when I replaced fuel pump.
But it might have clogged up already from all the crap on bottom of tank that sat for like 10 years. Thanks

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Guacamole
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Re: Fuel System Issue

Post by Guacamole » Mon Jul 01, 2019 7:28 pm

I'm no mechanic, so here's my 2c:
Did you drain the fuel tank when you changed the pump? I know it's not required as the pump is accessible from the top, but that's decade-old gas we're talking about that likely had ethanol added. The likelihood of that ethanol turning to water is pretty much guaranteed at this point. Plus since water is heavier than gas, it will settle at the bottom of the tank under the gas. When your tank runs low it means the pump is sucking up a higher percentage of water than actual gasoline potentially causing your engine troubles.
Just a thought.
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ZUBAJA
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Re: Fuel System Issue

Post by ZUBAJA » Tue Jul 02, 2019 2:55 am

While I haven't checked my Baja yet (never really thought about it until now), all my other Subarus also have a fuel filter up in the engine compartment. Other possibilities could be any pinched or deteriorated lines in the fuel evaporative system, charcoal canister, etc. Dennis

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kamesama980
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Re: Fuel System Issue

Post by kamesama980 » Wed Jul 03, 2019 10:47 am

Zubija: Turbos (and IIRC, later NAs) don't have a fuel filter in the engine bay. They only have the in-tank filter.
Guacamole wrote:
Mon Jul 01, 2019 7:28 pm
I'm no mechanic, so here's my 2c:
Did you drain the fuel tank when you changed the pump? I know it's not required as the pump is accessible from the top, but that's decade-old gas we're talking about that likely had ethanol added. The likelihood of that ethanol turning to water is pretty much guaranteed at this point. Plus since water is heavier than gas, it will settle at the bottom of the tank under the gas. When your tank runs low it means the pump is sucking up a higher percentage of water than actual gasoline potentially causing your engine troubles.
Just a thought.
Unless you know a whole lot more about fuel chemistry than I do, ethanol doesn't turn into water. It absorbs water rather than separating (like gas or oil) and creates more water in the combustion process than non-oxygenated fuel but it won't turn to water in the tank.

At 10 years old, the ethanol content is irrelevant, you have garbage in there and it needs to be removed.

Gregmy123: have you tested that it has problems at 3/4 tank (ie, filled it up and it ran fine till it got back down to 3/4 again) or it just started having problems and you happen to have burned 1/4 of the tank so far?
-Russell
"You don't get to judge me for how I fix what you break"
03 sport 5mt
05 turbo 5mt vf39 and other STI bits, 3" turbo-back

ZUBAJA
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Re: Fuel System Issue

Post by ZUBAJA » Sat Jul 06, 2019 6:15 am

kamesama980 wrote:
Wed Jul 03, 2019 10:47 am
Unless you know a whole lot more about fuel chemistry than I do, ethanol doesn't turn into water. It absorbs water rather than separating (like gas or oil) and creates more water in the combustion process than non-oxygenated fuel but it won't turn to water in the tank
Not to argue chemistry, water isn't going to turn into fuel, and fuel isn't going to turn into water. That we can agree on. From my experience down here, on a humid day (90% of the 365), you can take a quart of ethanol, pour it into a pan, and watch the surface become cloudy as it absorbs the moisture from the air. You can then cover the pan, come back a day later and there will be water in the bottom of the pan. This is because the water will separate from the fuel. I see so many small equipment failures for just this reason, there will be water in the tank or carb bowl even though the machine has not been left out in rain.
Likewise, especially with ethanol, I have seen fuel that was drained because of a no start and there is no water present. The old fuel however, will not be flammable enough for the engine to run. On these machines, fresh fuel and they crank right up. This is the reason that all my small equipment runs on ethanol free fuel only.
Regarding the OP's problem with running rough after a certain level, I don't think this involves fuel quality. Dennis

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Re: Fuel System Issue

Post by Gregmy123 » Thu Jul 18, 2019 1:14 pm

Guacamole wrote:
Mon Jul 01, 2019 7:28 pm
I'm no mechanic, so here's my 2c:
Did you drain the fuel tank when you changed the pump? I know it's not required as the pump is accessible from the top, but that's decade-old gas we're talking about that likely had ethanol added. The likelihood of that ethanol turning to water is pretty much guaranteed at this point. Plus since water is heavier than gas, it will settle at the bottom of the tank under the gas. When your tank runs low it means the pump is sucking up a higher percentage of water than actual gasoline potentially causing your engine troubles.
Just a thought.
Did not drain tank.
That was dumb of me.
I am pulling passenger side fuel pump and driver's side
fuel level sending unit.
And cleaning tank. And replacing filters.
And I am doing the Spray Seafoam thru Throttle Body procedure.


Thanks

Gregmy123
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Re: Fuel System Issue

Post by Gregmy123 » Thu Jul 18, 2019 1:21 pm

kamesama980 wrote:
Wed Jul 03, 2019 10:47 am
Zubija: Turbos (and IIRC, later NAs) don't have a fuel filter in the engine bay. They only have the in-tank filter.
Guacamole wrote:
Mon Jul 01, 2019 7:28 pm
I'm no mechanic, so here's my 2c:
Did you drain the fuel tank when you changed the pump? I know it's not required as the pump is accessible from the top, but that's decade-old gas we're talking about that likely had ethanol added. The likelihood of that ethanol turning to water is pretty much guaranteed at this point. Plus since water is heavier than gas, it will settle at the bottom of the tank under the gas. When your tank runs low it means the pump is sucking up a higher percentage of water than actual gasoline potentially causing your engine troubles.
Just a thought.
Unless you know a whole lot more about fuel chemistry than I do, ethanol doesn't turn into water. It absorbs water rather than separating (like gas or oil) and creates more water in the combustion process than non-oxygenated fuel but it won't turn to water in the tank.

At 10 years old, the ethanol content is irrelevant, you have garbage in there and it needs to be removed.

Gregmy123: have you tested that it has problems at 3/4 tank (ie, filled it up and it ran fine till it got back down to 3/4 again) or it just started having problems and you happen to have burned 1/4 of the tank so far?
I think you are correct. Crap at bottom of tank.
And car is running like crap no matter what the fuel level is. I am removing fuel pump assembly and draining/cleaning tank.
Thanks

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