...sequel to fuel tank suggestions!

[stephen low]

Had a go silver soldering my bung fuel tank and pipework but couldn't make it work on steel, same solder worked very well on copper, probably me.

Off to Kenmer where Marty fixed that but he also found another leak point pressure testing good chap so he sorted that out too.

Tank home and in and I take the beast for another test tonight and now my previously silent pump(s) are whirring their hearts out.

Am running a Carter pick up pump and Bosch 044 primary. Had read previously the Bosch are quite noisy but why would I now be suffering a lot of additional noise where previously there was none?

I haven't confirmed which pump is the noise source but am guessing the Bosch.

I though the cracked pipe might have been syphoning air but it would only do this through the Carter as there is a surge tank in between the two pumps as normal for an external system.

Can anyone suggest what might be causing this and how to combat another noise source?

Cheers

Steve

[Plums]

With all the work you've been doing back there it's possible that one of the pumps has picked up a bit of crap.... Or sometimes it can be a resonant effect at a certain length line, that may have been covered up by the leaky line...

Good luck!

[stephen low]

I've got a filter in line before the carter pump so wouldn't expect any rubbish to have reached either pump.

I was thinking that there may be something partially blocking the line and restricting flow, would a restriction be likely to increase pump noise?

I was under the car last night and didn't find any items touching metal work etc to give off a resonance type effect ie amplifying noise through contact but I might try a temporary clamp on the various fuel lines whilst I've got the car running to check it out for pipe resonance.

Anyone else got suggestions?

Cheers

[NASSTY]

Steve,
How's your diff noise going?

[stephen low]

Al

Can't hear the diff over the pump now!! But the additive made a slight difference but not enough to keep me happy.

Oh well just another job to add to the long list post engineering next winter I'm guessing.

As they say, a cobra work in progress.

Cheers

[Aussie Mike]

My Bosch 044 is very noisy too. I fixed it by bolting my short dump side pipes back on.

Cheers

[stephen low]

I could do the same with the stereo I plan to install!

But oddly, drove car this morning and no noise again from start up but just in travelling the noise came back with a vengance.

Fuel level in the tank was low and then I filled it up completely but the noise has continued somewhat.

However car was hunting a bit near the end and in fact backing into the garage idled to stop. I will check my filters tonight for blockage.

If these aren't terribly dirty, anyone got suggestions as to why the engine might be hunting up and down at idle like it was?

Cheers

[Gav]

Rich?
Too much pressure?
Or NAC.

Needs a Chev.

[stephen low]

Low and behold a primary filter full of crap, not surprising.

However another major issue.

Can anyone advise why I might get pressure in my tank sufficient to force fuel up the vapour line, through the cannister and out the vent. And I mean full flow from the vent line.

After cleaning my filters this morning and doing a bit more preparation I took it for a spin in Melbourne's 30 degree odd heat and it started hunting again but now it is pissing fuel out the front.

Has anbody some suggestions?

Am running the standard matching AU system including a new but now very soaked cannister, and the correct vapour lines and solenoid. I run a vapour tube out of the tank to the cannister and there is a vapour return from the engine to cannister and an atmosphere vent out of the cannister.

The vent line is highest on the cannister so there must be some pressure being developed to push out the amount of fuel that is happening.

Helpppppppppppppp, please!!!!

[Gav]

Got me there. How full is your tank?
Drain it half out and see how you go?

Sounds very strange to me. Sorry to be of no help.

[stephen low]

Tank was full admittedly but I seem to have used a lot of fuel over a very short distance and i think I am still getting fuel pushed out the vent.

Want to sort this for safety and fuel economy reasons to say the least.

Help again!!

[Aussie Mike]

The VN commodore tank I'm running has a trap setup on the vapor line. It's supposed to stops liquid going out the vent and only allow vapor. It's installed high up on the filler neck. There's 2 small vents from the top of the tank that lead up to it and another small one on the filler neck. a tube from the top of the trap goes to the carbon canister.

There's also a large vent tube 5/8" that runs from the top of the tank to near the top of the filler neck. This burps the air out of the tank when you are filling and stops any wash back cutting off the filler nozzel.

I've got a pic of it somewhere. I'll upload it so you can see what I'm talking about.

Is your carbon canister mounted down lower than the tank? It may be that your tank vent setup is siphoning fuel into it.


Cheers

[stephen low]

Thanks Mike

I'll look forward to the pics.

My vapour outlet is top front of tank beside fuel out and fuel return pipes, the same one that broke!

I do not know how the vent pipe is oriented inside the tank but the line runs down the tranny tunnel, lower than the tank and back up to the cannister which is located high up in the passenger side vent area higher than the fuel tank!

When I stopped to see what was happening on a few occassions you could see fuel and bubbles moving up the clear tube towards the cannister. Whether that was siphon effect or pressure in the tank or some other driving force was not clear.

It might be worth having a smaller vent high up on the filler neck rather than down at the tank.

Can anyone else comment on this arrangement?

Cheers

[Aussie Mike]

Thet vent point needs to be up as high as you can get it. I reckon that's your problem I'd move it to high on the filler neck if possible.

The tank vent should be plumbed up to the filler neck as well so it can purge the air out of the tank.

If you haven't got a barb on the neck bring round and I'll weld one on for you.

Cheers

[stephen low]

Mike

Thanks for the offer, but as Kenmer is only nearby I'll pester Martin.

Had already talked to him about this and another sensible move is to relocate the charcoal cannister out of the engine bay.

Perhaps my driver's side rear wheel arch is now to be as busy as the passenger's one.

But I reckon your right about the height so it has to happen.

Cheers

[Aussie Mike]

Hi Steve,

Here's my setup. There's also a clamp installed on the main vent hose now. This was taken as I was setting it all up.



Cheers

[stephen low]

Thanks Mike.

Cheers

Steve