Help Troubleshooting Subaru 3.6L

[Ultramaroon]

It's not valve springs. Poor idle and sudden improvement under load? No way.

[Spuds]

On today's episode of Spud's Subaru Saga, Spuds learns about in-tank rollover valves...

I need to get a thinner (and probably longer) hose...

[Ultramaroon]

Originally Posted by Spuds

On today's episode of Spud's Subaru Saga, Spuds learns about in-tank rollover valves...

I need to get a thinner (and probably longer) hose...

Hose for siphoning? Tell me about the rollover valve. I don't see it in any diagram.

[Spuds]

Originally Posted by Ultramaroon

Hose for siphoning? Tell me about the rollover valve. I don't see it in any diagram.

Apparently modern fuel tanks have a check valve where the filler neck and vent meets the tank to prevent the gasoline from spilling out in a rollover. No it's not on any of the parts diagrams, so I am assuming it is integrated into the fuel tank itself. If you look up "how to siphon fuel from a modern car" you will see that a lot of people encounter this problem and the solution is usually to use a 1/4" OD tube. I had a 3/8" tube and while I did seem to make it fit through the valve it had too much resistance to get it further into the tank.

Edit:. To answer the first question, yes, I need a thinner and longer tube for siphoning. Not sure why I said hose lol.

[Ultramaroon]

I've struggled with that flappy valve in the past. How far can you get your hose? Does it maybe hang up on the sharp bend nearest the tank?

[Spuds]

Originally Posted by Ultramaroon

I've struggled with that flappy valve in the past. How far can you get your hose? Does it maybe hang up on the sharp bend nearest the tank?

It's hard to tell, there are a few bends I can feel it getting through on the way down, but hard to judge which is which when you can't even see the tube. I think a thinner hose might help a bit there as well.

[jflogerzi]

Transfer pump? HF has a good one for 10$

Sent from my GM1915 using Tapatalk

[Spuds]

Originally Posted by jflogerzi

Transfer pump? HF has a good one for 10$

Sent from my GM1915 using Tapatalk

Where would you connect the transfer pump to get at the fuel?

[jflogerzi]

Long skinny tube? IDK.. I was tired when I posted this

Sent from my GM1915 using Tapatalk

[Spuds]

Alright, got the tank draining now, more on that later.

Any of you all know if there is a typical way to remove subaru seats without removing the rails?

[Spuds]

Well, the good news is that I successfully replaced the fuel pump assembly without lighting anything on fire. The bad news is that it was ineffective in solving the problem...

Only other thing in the tank I can think of is the sending unit on the other side of the tank, which has its own fuel inlet and filter, feeding the pump through a line crossing above the tank. Maybe that is clogged or the line is messed up somehow?

I guess injectors next?


PS. Anyone need a perfectly functional OEM Subaru Tribeca fuel pump assembly?

[Ultramaroon]

Are you absolutely 100% sure that those plugs at 5 and 6 are firing? Can you get at the power for the igniters to unplug them while the engine's running? If it runs worse, or dies, then that cylinder was firing.

You can also remove the igniter and test it using a new plug and a ground strap. Testing is key. Think of how much time and effort went to replacing all that perfectly good shit.

I've dealt with simultaneous seemingly-independent failures. It's rare but it happens. I've also dealt with a couple engines that were consistently wrong in how they reported misfires.

[Spuds]

Originally Posted by Ultramaroon

Are you absolutely 100% sure that those plugs at 5 and 6 are firing? Can you get at the power for the igniters to unplug them while the engine's running? If it runs worse, or dies, then that cylinder was firing.

You can also remove the igniter and test it using a new plug and a ground strap. Testing is key. Think of how much time and effort went to replacing all that perfectly good shit.

I've dealt with simultaneous seemingly-independent failures. It's rare but it happens. I've also dealt with a couple engines that were consistently wrong in how they reported misfires.

Well, I swapped both the plug and ignition coils forward a cylinder, so 6-->4, 4-->2, and 2-->6 and it is still showing misfires on 5 and 6. Plugs looked fine themselves. I only did the left bank though, I could try the right bank but there is more shit to remove to get to the plugs. The only plugs for the coils are right on top of them, and being a boxer, I don't really want to stick my head between the engine and frame rails. Plus, I need to remove the battery to get to one side, the air intake to get to the other.

Yeah, there is a possibility that it is reporting misfires incorrectly. It definitely feels like a misfire, but it could be reporting which cylinders are misfiring incorrectly.

[Ultramaroon]

What would cause misfire through the first third of engine speed? Vacuum leak? Dirty MAF sensor?