In tank fuel pump

Kai · Posted: Sun Mar 16, 2014 10:58 am Post subject:

The return is the additional 8mm one, the other one should be slightly smaller 6mm and this is the tank vent which connected to the charcoal canister.
_________________
Think......

Don't sleep and drive!!!

M@H · Padawan Joined: 16 Oct 2012 Posts: 52 Location: Cornwall

Many thanks for the reply! and yes you are right, one is smaller than the other two.

Whats baffling me now is that I have 3 fuel lines to/from the engine though !? One goes to the swirl pot/filter type thing (which I assume is the flow), one has a "button" shaped thing about 40mm across on it (which I guess is a pressure regulator (?) and is a return), and the other one is just connected to the rail somewhere (and I assumed was another return?). They are all together on the right-hand side of the engine.

Irritatingly I wasn't able to get the tank and pump from my donor car so I was unable to trace the 3 pipes back down the car.

Any thoughts?

Many thanks
Matt.

Kai · Posted: Sun Mar 16, 2014 7:59 pm Post subject:

8mm flow with the fuel filter on it

8mm return with the 40mm fuel pressure regulator ( picture olease as all sounds right but would rather have confirmation )

6mm fuel tank vent. Should be connected to a purge control valve if yours had one fitted which is underneath the Inlet manifold.

Simples.
_________________
Think......

Don't sleep and drive!!!

M@H · Padawan Joined: 16 Oct 2012 Posts: 52 Location: Cornwall

Ok I'm confused :-)

So, I have three pipes:

Two black ones and a blue one.

The bottom black one goes into the swirl pot/filtery thing, then on to the solid pipes
The top black one goes into the 40mm button type thing, then on to the solid pipes
The blue one in the middle just goes straight to the solid pipes.

All three join up with the engine at the three solid pipes next to each other.

So, which one does what :-) I realise I am probably appearing a bit thick at this point, its a bit difficult when the donor car is a year out of sight.

Many thanks,

Matt

Kai · Posted: Mon Mar 17, 2014 4:54 pm Post subject:

Swirl pot is actually the fuel filter and this line is the fuel injection feed from the tank.

Black 40mm regulator is the fuel tank return line

The blue one is the tank vent which you connect to your Vw fuel tank vent line.

What year is that engine? Looks phase one.
_________________
Think......

Don't sleep and drive!!!

M@H · Padawan Joined: 16 Oct 2012 Posts: 52 Location: Cornwall

..so the Tank vent feeds back into the engine then !? (having gone through the carbon canister I assume)

Year = 2003 it was a 53 plate impreza so not Phase 1.

Many thanks again,
Matt.

Kai · Posted: Tue Mar 18, 2014 12:02 pm Post subject:

Tbh I'm not sure on its exact operation. Well the science behind it

I know the charcoal canister filters the air and removes the smell of fuel from the air entering and exiting the fuel tank.

Their is a purge control valve which regulates this I believe.

Pretty sure somebody told me they left it open and it pissed fuel out. Was a long long time ago.

With my system, I have on the fuel tank filler pipe, I had the VW breather which is about 6mm, this originally went high underneath the bonnet ( I have a type 3 ) and round to the opposite for of the vehicle. I changed it to replicate the Subaru system. The original Vw breather now has been extended to the metal hard line on the engine you pictured. I can't recall exactly, that hard line goes underneath the Inlet manifold to the purge control valve, then onto the charcoal canister. This is assuming you have a European vehicle and not an import. Also I only really know early classic Impreza's.

So in a nut shell joint your fuel tank vent onto that third 6mm line, providing you still have the charcoal canister. If you don't then is suggest researching the Subaru forums on a mod for ditching the charcoal canister..... Or leave it as per the original fuel tank vent ( sure your used to the petrol scent already) and research if you can simply block or leave it open.
_________________
Think......

Don't sleep and drive!!!

M@H · Padawan Joined: 16 Oct 2012 Posts: 52 Location: Cornwall

Very interesting.. thank you

So I have the engine end, and nothing else. I've got a standard in-tank pump from another car, and have made a new fuel tank.

Interestingly the splitscreen fuel tank doesn't have a tank vent, just the filler neck and the outlet at the bottom, so I'll need to create all the pipework to make it work (not that its far from engine to tank :-D )

The standard subaru system has some bits and bobs between tank and cannister

And it seems that ultimately the purge control solenoid valve would be operated by a signal from the ECU, which I am wondering if RJES have included in my loom (expect so) - I will have to check with Richard.

So if the signal isn't there, that means if anyone connects their tank vent to this line is not actually going to be venting at all (as the valve will be shut all the time)

More research needed, but in any event I think I'll get a canister and at worst I can vent to air on the other side of it.

Cheers,
Matt

Kai · Posted: Wed Mar 19, 2014 2:13 pm Post subject:

I guess with a splitty it's using a none sealed filler cap allowing the tank to replace spent fuel with fresh air. This is if there is not factory vent.

That diagram....

Between the fuel cut valve and the rollover valve, about where the white arrow is. Thats approximately the position of the metal pipe connection you pictured, with the flow and return. The rest of the piece pictured are going to be attached to the engine ( apart from the charcoal canister ).

The purge control solenoid valve is part of the engine harness, ( I've no idea if rich modifies this, there is no need too ) 2/3 large grey multi pin plugs going from the engine harness to the rest of the vehicle harness. The rest of the vehicle harness is what I imagine you send to Richard to be modified.

My type three fuel tank, at the top of the filler neck ( in Layman's terms ) near the filler cap, I have a 6mm outlet which I've run to the engine to connect to that 6mm pipe pictured. The rest is all Subaru at the engine end.

To get by it, leave your tank venting via the cap and plug the vacuums line to the purge control solenoid and that should see you by I think if you wanna cheat.
_________________
Think......

Don't sleep and drive!!!

M@H · Padawan Joined: 16 Oct 2012 Posts: 52 Location: Cornwall

..indeed, the splitscreen tank must rely on the cap gently leaking air into the tank. Thanks very much for the comments on the rest of the workings.

Just had a reply from Richard, his comment was:

Your ECU will pulse the purge solenoid normally. Don’t plumb the purge pipe to your fuel system unless you fully understand what you are doing. Doing so without fully understanding the system can easily prove to be an expensive mistake. Just leave the tank to vent to atmosphere as VW intended. Block the purge port at the throttle body, but plumbing wise, you can do whatever you want with the rest of the purge pipework then, as it is no longer connected to anything. Don’t remove the solenoid electrically though, otherwise you’ll get error codes.

..I'll come up with something Happy

Kai · Posted: Wed Mar 19, 2014 6:43 pm Post subject:

http://www.type-ra.com/subaru-forum/threads/fuel-evaporative-system-any-knowledge-on-this.14479/

Interesting read above.

I don't have the one way valves in my system. Think I might have a rethink on how I'm venting my tank though.... Although it hasn't proved to be of any problem so far.
_________________
Think......

Don't sleep and drive!!!