Long Range Petrol tank access issue

[mudnut]

Probably chiming in too late, but there should be a line for the breather, a line for fuel out and a fuel return line as the RB3O has a return solonoid that allows fuel to flow back to the tank under 1400-1500 rpm. I am guessing that there would have to be a way of switching the return from either tank, wouldn't there.

[dom14]

These are the plumbing connections.

[dom14]

Probably chiming in too late, but there should be a line for the breather, a line for fuel out and a fuel return line as the RB3O has a return solonoid that allows fuel to flow back to the tank under 1400-1500 rpm. I am guessing that there would have to be a way of switch the return from either tank, wouldn't there.

Never late mate. Thanx for popping in.
I'm going at it slowly as usual. I worked out all the plumbing as above.
I think I should replace all the rubber and flexi plastic fuel hoses that goes from fuel line to the tank.
Old ones are pretty stiff & not so flexible.
BTW, mine's dual fuel. The tank showing in the pictures is the only one.

Just wondering mate,

1)What happens if the fuel return solenoid gets faulty and doesn't open up the valve for the excess fuel to return back to the tank?!
Can it damage the fuel pump or simply overflow from the carby?!

2)BTW, have I been accurate with my assumption that if the fuel bowl in the carby is half full all the time(from sight glass), there in NO pumping weakness from the fuel pump?
(The issue is intermittent failure of the pump or wiring connection weakness somewhere, I think)

3)Do you know the specs of the stock fuel pump(the one in the pictures)?

4)There is NO strainer inside the tank for the pump pickup. Is this a concern?
Should there be a one? I looked inside the tank. It looks pretty clean, and I can't see any strainer floating inside the tank (dislodged from the pump pickup for any reason)
I'm wondering whether some petrol gunk got buildup inside the pump over time due to not having an intank strainer/filter, causing the pump to fail intermittently(mechanical failure rather than electrical).

[mudnut]

Sorry abridged answers only as I hit the wrong button and lost my detailed ones.

1) I am hoping/ assuming the fuel return solenoid is to lengthen the service life of the pump and that failure to operate doesn't cause a major problem. To pump against pressure takes a lot of energy.

2) If the fuel is at the correct level, then the pump is operating properly. It would be good if you could see the level drop, indicating failure. An elcheapo camera from SCA might be the go.

3) I don't know the specs of the pump, but Alitis 007 might.

4) From memory, in any vehicle I have had to inspect the pick up, it usually has a strainer. The manual only shows a picture of the TB or TD pick up which has a strainer.

EDIT: The only failure of the return system I know of was that the solenoid was sticking and dropping the fuel pressure so high revs couldn't be acheived.

[dom14]

Sorry abridged answers only as I hit the wrong button and lost my detailed ones.

1) I am hoping/ assuming the fuel return solenoid is to lengthen the service life of the pump and that failure to operate doesn't cause a major problem. To pump against pressure takes a lot of energy.

2) If the fuel is at the correct level, then the pump is operating properly. It would be good if you could see the level drop, indicating failure. An elcheapo camera from SCA might be the go.

3) I don't know the specs of the pump, but Alitis 007 might.

4) From memory, in any vehicle I have had to inspect the pick up, it usually has a strainer. The manual only shows a picture of the TB or TD pick up which has a strainer.

EDIT: The only failure of the return system I know of was that the solenoid was sticking and dropping the fuel pressure so high revs couldn't be acheived.

The reason I asked the Q2 is 'cos carby isn't going well with petrol atm.(in addition to the pump problem).
Just to rule out any fuel level issues in the carby float chamber, when the engine's stalling(hard to achieve higher revs & short of power), I quickly got out of the vehicle and checked the float level, which showed good. I'm not sure that's a reliable way of testing to see the
carby float level on a driving car. I presumed float level cant be low while I'm driving and kick in that quickly during few seconds I need to get out of the car, open the bonnet and see it. The problem goes away after engine warm up.
It's not a auto choke issue, as i've played with the choke already. I know I'm complicating the issue here by bringing in an
unrelated issue to the main topic of the thread.
I thought the best approach is to rule out all the fuel pumping issues first and then get to the carby.

It runs fine on LPG though.

If I understood you correctly, not having a strainer inside the tank is NOT a good thing. If TBs got it, then RB30s should have it as well.

I would have to find that out beforehand, if I'm to install an intank pump same as the stock one.

[mudnut]

Sounds similar to the second stage sticking while cold.

[dom14]

Sounds similar to the second stage sticking while cold.

Did you mean the secondary throttle valve? It's ok with LPG though.

[Bigcol]

I think Mudnut is referring to the "needle & seat" - that governs the fuel level in your carby

you say you have not done / touched / played with the Carby yet, just trying to eliminate the fuel tank / pump as a source of the problem.............?


I would be putting a carby kit through as soon as you have finished sorting the tank / pump

not ALL Nissans have a filter on the fuel pump - the L24 & L26 did not have, but the L20 & L28 did............... go figure

[dom14]

I think Mudnut is referring to the "needle & seat" - that governs the fuel level in your carby

you say you have not done / touched / played with the Carby yet, just trying to eliminate the fuel tank / pump as a source of the problem.............?


I would be putting a carby kit through as soon as you have finished sorting the tank / pump

not ALL Nissans have a filter on the fuel pump - the L24 & L26 did not have, but the L20 & L28 did............... go figure

Fuel pump/related electrics definitely have a problem. As you might have seen from the pictures, LRA has done a poor job with electrical wiring for the pump & sender near the tank. Probably one of causes of the problem, if not the whole reason.
I am putting the pump through proper diagnostics regardless of that to make sure it's not on it's way.

Carby's been through a kit not that long ago.
Float chamber fuel level is usually good. Originally it was always quarter full, but last year I adjusted it to be half full all the time.
It went ok since then.
Having said that, since I started having fuel pump issues, I started giving the fuel pump power directly from battery, bypassing the
Fuel Pump Control Unit(Fuel Pump Relay).
That caused the carby to flood few times so far.(as soon as I connect the direct power line to the fuel pump).
So, it sounds like carby also developed a problem.
I don't think it's likely the fuel pump to put out excess pressure.
Fuel pump start getting weaker when they are on their way out don't they? They don't develop extra grunt before they die, do they?

[dom14]

Fuel pump internal/external connections.