Hi

Ive noticed that when turning the ignition on, the fuel pumps prime but then sound as thought they keep going until I turn over the car. Is this normal? For me they used to prime and then stop until I turned over the car. Is this something that warrants attention?

Thanks in advance
Mike

 

I hear my fuel pump for a second or two,then it stops. I assume that is when the float chambers are full.

 

Clarkes's car is normal.

They prime up the bowls, then stop, and continue again when fuel is consumed from the carbies.

If they are running constantly, the first search is a fuel leak, either externally, or into the engine via the carbies.

 

Thanks for the replies Grant and Clarke

I can't notice any around the tank or pumps themselves. So more likely to be around the fuel lines you think? So does that mean there is no problem with the pump themselves? Sorry for the dumb questions.

Cheers
Mike

 

Consensus indicates that the pump/s MAY be fine.

A SU pump with a diaphragm on the way out may pump constantly, as some fule is by-passing inside the pump itself.

I would be removing the fuel supply hose AT the front carby branch, and plug the hose properly. Turn ON the ign, and note if the pumps still do the same thing.

If they do, I reckon there is a leak somewhere, and you really should smell it, as our fuel really does stink.

If it ceases the pumps once pressure is up, then the carbies are at fault.

There is a fuel hose up above the rear suspension cradle on the RH side, and is easily FELT, but almost inpossible to SEE. This hose is OLD now, and may be a thing to add to the TO DO list.

Just take your time, and keep to a system, that way doubling up is reduced.

The carby 6 cylinder cars do not have a fuel return line down the LH side, so one less hose to deal with.

The needle and seats inside the carbies can be problematic simply due to age, so new ones from time to time does no harm.

 

I would think if you have a fuel leak big enough to keep the pump running you would smell the fuel and be able to see it dripping somewhere.
I know when my float chamber needle got stuck I had fuel running out of the overflow within seconds.

Here is a pic of where the fuel line exits the spare tyre well at the front right(looking into boot from the left of the car)
And the second pic shows where to find the fuel line route is above the cradle(taken with the cradle removed) from the left wheel arch.

these 1000's of pictures I have taken of this car do come in handy from time to time.

 

Actually, looking at that second picture now really sinks in how close the fire was to the fuel line, the hottest part was right below that pipe. Just imagine if it was newer car with rubber hose.

 

Thanks for help guys. Really appreciate it. I've checked around the pumps and the hoses in the boot. I've looked under the car and can't see any evidence of a leak as yet. The left pump is the only one doing it. I can't see any leakage around the carbies. There is a faint smell of petrol in the cabin. I've stopped driving her for the time being, as I don't want to risk any damage or fires!

I spoke to my mechanic, he seems to think the pump is on the way out. He suggesting I replace it as the pump hasn't been looked at for quite a while. So it's going in next week to get that looked at. Hopefully just a pump issue and not any problems with the hoses.