Fuel leak !!

[vimal]

I’ve just started my 1970 2.2 S which has been standing still since lockdown - it started fine but there is a pool of fuel which has been leaking from some where under the front of the car. I can’t see any sign of damage to the fuel tank - does anyone have any idea of what it could be? Any thoughts gratefully received.

Vimal





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[Berny]

I have known the mettle pipe from the tank to the pump to rust and hole the fuel pump is at the front on a 1970 car covered by a plate 4 bolts 13mm if I remember

[Lightweight_911]

.

If the fuel has been leaking from the front of the car whilst the engine is not running it must be either the fuel tank itself or the screw connections at the bottom rear of the tank.

.

[vimal]

Thanks both. The leak happened only when I started the car - and the volume that came out suggests that there it’s more than a small leak.

At the risk of sounding really stupid there is a tube under the bonnet which isn’t connected to anything - could this be the cause ?


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[vimal]

Another pic


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[stretch]

That hose should exit through the front bulkhead alongside the washer bottle. It is the vapour hose from the black box behind the dash.
It won't be that. If you don't see a leak from the rear fuel tank fittings take off the protective plate so you can see the fuel pump and hoses. That should reveal the problem.

[inaglasshouse]

Hi Vimal,

Indeed, as Dave says... fuel pump is located next to the steering rack on these, so up the front. Remove the protective plate (underneath, covering the steering rack) and take a look. It will probably be one of the hoses tank -> pump -> fore-aft lines which run through the transmission tunnel or, very likely, the pump itself.
The pumps all leak eventually, only a matter of time!
You can get new pumps from Porsche, which are decent these days (used to be rubbish, so only buy from OPC so you definitely get a recent one, and make clear that you won't accept it unless is has a "Made in Germany" sticker on it), but a tad overpriced. Better options (price vs performance) exist in the wider world and fit in the space, but depends if the originality aspect bothers you.
The Porsche one does look pretty authentic.

PM me if you want details of what I used, having given up on several leaky Porsche pumps...

Good luck, have fun.
Cheers, Richard.

[Simon Rudge]

First look would be at the hoses in the tank/pump area. if they are older specification, modern ethenol fuel will degrade them over time, leading to leaks. Far too common. As it started when you fired the car up, most likely between the pump and the solid line down the tunnel.

If you have them replaced, make sure they are to at least R9 standard, or you can use biodiesel hose, which resists just about everything. Also, make sure you use the correct clips for smaller diameter hose, jubilee type clips can leave a little weep point as the do not cover the full way round the pipe. Not a difficult job, just messy.

[vimal]

Thank you all - that’s really helpful information. Richard - what you have said about the fuel pump is reassuring as I was expecting something more serious and so I hope it is just that. I will update. Were the fuel pumps very different in MY 70 cars to later ones?

Vimal

[inaglasshouse]

I know the location changed for later cars (moved to the back of the car, near the LH rear wheel well I think). No idea if the pump changed - not my period!
Note - MFI pump is different from carb pump. Different pressure and flow rate requirements.

[BILLY BEAN]

I know the location changed for later cars (moved to the back of the car, near the LH rear wheel well I think). No idea if the pump changed - not my period!
Note - MFI pump is different from carb pump. Different pressure and flow rate requirements.

Same pump for 1970 and the later 1972 if MFI. Pump at the rear for 1972/3. The rear mounted pump is nestled in a "cradle" close to the end of the torsion bar tube on the left hand side of the car.

[vimal]

An update - some good news - the pipes leading to the pump had split - the pump itself is fine. Hopefully all resolved!


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