15 replies to this topic

[Ian Mac]

Hi
I have just got our 1988 Mini City back on the road after being laid up for a few years.
Every now and again petrol is leaking from around the fuel pump while the engine is running.
It does not happen all the time but when it does it looks like fuel is being pumped out from beneath the pump its self.
The inlet and outlet rubber hoses look OK.
Llooking from under the car there is a small hole in the bottom of the pump, is it possible for fuel to intermittently leak from there?
I cannot make it do it while I am under the car watching but when it does leak fuel is pouring out

Thanks
Ian

[KernowCooper]

If fuel is leaking from the hole in the body the pumps diaphram is leaking and small splits in the diaphram is allowing fuel through, the danger of this is that fuel could also get into the crankcase and gearbox and dilate the engine so the oil then does not have the correct lubrication properties and serious engine damage can result. The currrent pumps are mostly cast and the body is pressed or staked together so unlike the old pumps where you took out a load of screws and replaced the diaphram nowdays its a new pump assembly.

If you suspect its been happening for a while I'd also change the engine oil and filter to be on the safe side.I'd not drive the car until you get a new fuel pump and change the oil and filter

Edited by KernowCooper, 02 March 2013 - 07:04 PM.

[Ian Mac]

Thanks for the information, I will fit a new fuel pump and check the oil. Will probably be OKwith the oil though as it has only done a few miles and the problem is very intermittent. There do not appear to be any screws in the pump so it may have alread been changed at some stage.

[KernowCooper]

All pumps now on the A series will be the pressed together type if its mechanical nowdays. if it has been pooring out as you say I'd drop the oil

Edited by KernowCooper, 02 March 2013 - 09:55 PM.

[Ian Mac]

good advice - thanks

[MRA]

Just out of curiosity does your Mini have an LCB manifold fitted ?

[Ian Mac]

Not yet fortunately, I have one to fit with an RC40 but am waiting to get a Y piece.


I already have a burn on my hand from trying to feel the fuel pump with the engine running!

[MRA]

Then for safety reasons you should fit an electric pump.... the mechanical pump is too close to an LCB to be safe, yes loads of people still go ahead and fit them, however I wonder how many of you would be able to reply to this post after having a petrol fire in your car ?

Think about it..... you say yourself that you have petrol leaking out all over the place and you are thinking of fitting an exhaust manifold that is right next to the pump ??

[se_juggles]

Chances of fuel igniting on the exhaust is almost zero. You'll be Suprised how many minis have these fuel leaks and its been gushing out for months and all they say I've had a strong petrol smell coming from my engine for a while.

Personally I replaced mine for an electrical pump and its caused my carb to over fuel. I completely leaned off the carb and it still ran quite rich. If your going to get an electric there are other parts you may also need to replace.

[Dan]

You are not fixing the right problem by leaning off an engine in that situation, it's not rich because its setup wrong. Leaning it off may result in overheating and severe engine damage. The problem is excessive fuel pressure and the solution would be either a new needle valve or a new or adjusted float, or an in-line pressure regulator. Carbs only need a very low pressure and it is quite normal to fit a regulator along with an electric pump.

[se_juggles]

I know the needle is replaced now. that is what I was saying. Leaning off the engine didn't even prevent the fuel being taken in one bit because the pressure from the electrical pump was to strong for the original needle.

Sorry maybe I didn't state my comment clearly.

[se_juggles]

Needle setup should I say. Typing to fast on my phone. Can't keep up with myself.

[MRA]

All electric pumps need a regulator.

The ones that say they have a strong smell of petrol fumes ...... these are the lucky ones, a hard drive, lean mixture or retarded ignition can all head towards a red hot exhaust manifold, this can ignite fuel vapour quite easily.

Or a broken ignition cap leading to tracking, I have seen petrol pipes resting against manifold down pipes, so at the very best case you may easily end up loosing lots of valuable petrol.

[cal844]

Then for safety reasons you should fit an electric pump.... the mechanical pump is too close to an LCB to be safe, yes loads of people still go ahead and fit them, however I wonder how many of you would be able to reply to this post after having a petrol fire in your car ?

Think about it..... you say yourself that you have petrol leaking out all over the place and you are thinking of fitting an exhaust manifold that is right next to the pump ??

erm... i have an LCB with mechanical pump on my 998. we changed all pipes, made the pump to carb pipe a different shape so it could be cable tied to the bulkhead.

[MRA]

erm... i have an LCB with mechanical pump on my 998. we changed all pipes, made the pump to carb pipe a different shape so it could be cable tied to the bulkhead.

Not a good idea really....

What you now have is a pipe that should be going from pump to carb, actually going from pump to bulkhead to carb !

Have you catered for the engine movement due to torque and gear changes ?
Do you even know how much your engine moves under these conditions ??

Most people don't have any idea of the amount of movement their engine goes through when changing gear or simply accelerating etc.... ask anyone whos watched a Mini during a dyno test.

The bottom line is that its up you which fuel pump you use....... Im just letting you know that its not a good idea to use a mechanical pump near to the LCB exhaust manifold