Arghh - help

[Jamieg285]

As you will have read elsewhere, part of the recent batch of work was to remove the fuel tank to fix the boot floor. All seemed to go well at the time, but things have got worse by the day:

Problem 1: The primary side of the carb was slightly overflowing every couple of minutes, causing a stumble.  I figured this may have been some dirt dislodged and causing an issue.  I took apart the filter and float blow, cleaned a blew it through. No real issues spotted.  Result - now overflows a lot more - to the point were it was almost permanently stubling and almost undriveable.  Last night I replaced the needle and seat with a brand new one to remove any possibility of damage being an issue, and also swapped the float in case this one was getting soaked and sinking.  End result - slight improvement, runs fine with sight plug on side of bowl is removed, but starts to overflow when it's refitted - oddly, the fuel level appeared to remain constant at this time.  However, it was driveable again.
n.b, the warmer the car got, the worse the problem was - at all stages.

Problem 2:  This morning I drove happlily for 5 minutes to the petrol station to fill up (Yesterday's overflowing used a LOT of fuel).  After the petrol station it was a total dog, permanently overflowing a lot - Stalled twice, and after the 2nd time wouldn't restart - just throws fuel out of the top when cranking.  I figure this could the replacement float has also sunk, and will look at this tonight.

Problem 3 : this is where I need some suggestions.  Whilst parked up waiting for the AA, a work colleague pulled up to help, and pointed out a rather large puddle at the back of the car.  A quick look underneath found petrol pissing out of the seam.  After about 10mins the flow stopped, and the gauge is still showing 3/4 full, so I'm thinking it must be a pressure releated issue.  

Anyway, the question now is - can the fuel tank be repaired, CHEAPLY and easily?

All suggestions welcomed.

Cheers,

Jamie

[F Body]

It sounds like the opposite of a vacuum / breather pipe problem ?

What I can't figure out is where the extra pressure is coming from

[Roadkill]

I remember when Martyn drilled a hole in my Camaro's old tank . . . .

I replaced that.

You can get a tank leak fix putty (like Chemi-metal) that sets even in the pressence of fuel.

However if it's on a seam then it's gonna be a b@stard.

I'd recommend a tank sealer - try ebay searching Kreem tank sealer - that's what I used on the bike (I had several pin-holes) and it's fooking marvellous stuff.
Always best to drop the tank as you need to work it around the tank.

As far as the fuel gushing out goes . . . dunno - Your tank is probably like mine so will have a drop-down breather (try cleaning that out).

Also check the return fuel-line . . if that's blocked the fuel will have nowhere to go but out.

Do you run a manual fuel pump ?

[Jamieg285]

I'm going to try some putty.  It's on the seam, so I'll just have to try my best. Doesn't need to be permanent, but last a good few months until there's more money in the coffers.

It's a mechanical pump, no return line.  Never had a problem with it before.

AFAIK, there should be a sock filter on the pickup in the tank, then nothing until after the pump, where I've got a regulator, filter and gauge. PSI is showing as 4.5-5 which should be fine, low if anything.  Checked filter and it's clear.

I'm stumped. The Holley tech support have suggested 3 things, but I've done all of those already (needle/seat, float level and pressure) It could be percolation, but it doesn't feel like it's getting too hot (cool enough to keep a bare hand on the bowls) and it's never had this problem before.

Anyone got a spare carb lying around?

[Roadkill]

Quoting: Jamieg285

gauge. PSI is showing as 4.5-5 which should be fine

Yup - if anything a tad low.



Let me have a think . . . It's certainly an odd one.

[Jamieg285]

Re the tank fix, I thinking along the lines of a large dop of the filler into and around the seam, then clamp a folded strip of aluminium over the top and bottom to act like a cap: (excuse the ASCII art)

      ___      / --- / | ==      Tank --- \      \____

 
 
 
 
 
 



I can probably run some screws through the ally and the seam to hold it all together and in place.

[Roadkill]

Quoting: Jamieg285

I can probably run some screws through the ally and the seam to hold it all together and in place.

Providing the tank filler adheres to the tank I'd say adding screws would only make it worse - certainly no better.

It was on a seam (on the corner) where Martyn drilled mine - It seeped out permanently after that.

[Jamieg285]

OK, maybe I can work out a way to add the screws to the ally to clamp it down, without the screws going into the tank metal.  

I'll need to take a proper look at exactly where the hole is and work from there.

[Big Mouse]

Is the regulator working correctly? I'd do a flow check before doing anything else - apart from the tank leak of course!

[Rob]

Might be of use..........

http://cgi.ebay.co.uk/Pontiac-Firebird-Trans-am-Camaro-parts-/230546097061?pt=UK_CarsParts_Vehicles_CarParts_SM&hash=item35ad9e43a5

[Rocky]

Thats mine, I do have a good tank out of it but someone is supposed to be picking it up unless you can come sooner.

[Rob]

Quoting: Rocky

Thats mine

Thought it might be....

[Jamieg285]

Quoting: Rob

Quoting: Rocky
Thats mine


Thought it might be....

As did I.

The 70 tank is a different shape to the 79, it doesn't have the hump on the top right.  Will it still fit?

PM sent.

[Jamieg285]

Quoting: Big Mouse

Is the regulator working correctly? I'd do a flow check before doing anything else - apart from the tank leak of course!

There's a gauge inline that goes up and down correctly and has been consistent ever since it was put on.

That said, I will be doing some testing of the pump at the weekend.

[Jamieg285]

Picked up some 'Plastic-Padding Stop-Leak' from Halfords.  Says it's suitable for petrol tanks, so fingers crossed.

[Roadkill]

Quoting: Jamieg285

'Plastic-Padding Stop-Leak'

Yup - that's the stuff - used that before on one of my cars - the Hawk I think - did the job.

[Jamieg285]

All is good again


Discovered that it's not the tank that's leaking, but the main supply pipe from the sender unit.  A pin hole that is only leaking when there's pressure in the system was leaking out onto the top edge of the seam and running to the corner before dropping off to the floor.  

Not the easiest of jobs when the tank is full of 60litres of fuel, but I dropped it again, cut the sender line well forward of the rusted area and attached a run of flexi pipe from there to the hard line on the frame.  Lifting the heavy tank back into position was a challenge and I nearly sheared of the filler neck doing it, but with some ingenuity I did get it into place and bolted back in.

With the leak there fixed, the carb is now behaving itself again, although I still can't work out how a hole in the feed line would cause the symptoms I did. Still, all's well that ends well.   And as a bonus, because I only spent £7.50 on a fuel line, rather than £250 on a tank, I can still get my smartphone for xmas

[Roadkill]

Quoting: Jamieg285

And as a bonus, because I only spent £7.50 on a fuel line, rather than £250 on a tank, I can still get my smartphone for xmas

[Andy]

Quoting: Jamieg285

With the leak there fixed, the carb is now behaving itself again, although I still can't work out how a hole in the feed line would cause the symptoms I did.

Best to put it down to 'one of those things'.

Good work though!