fuel pump heating and jamming

hello guys
I did a 340 km trip today and around the 140 mark my landy suddenly started to choke and stop and choke and stop till finally went dead. Pouring fuel in carb and restarting was no help (wouldn't stay on) so I called my mechanic and he said your fuel pump is heated and jammed. "Put a piece of cloth dampened in cold water on fuel pump and let I sit for 5 minutes it will be OK". I did this and that did the trick for another 75 km till same process had to be repeated. What can I do to fix this problem myself without going to mech.
tx in advance
ps 1985 - 2.5 petrol 88 , today was a hot day, The pump is original LR and was bought and installed 4 months ago.

you could fit a mechanical lift pump

Thanks for your reply. Sorry for ignorant question but the pump installed on my truck looks like the image attached bellow, which is what I found when I search for mechanical lift pump. Is lift pump something different than fuel pump? what at am I missing here?

you have mechanical pump then ,perhaps another pump or new oneway valves,

If its a hot day it won't be jammed but "vapour locked". This is particularly bad with any fuel that contains ethanol, I found that different brands of petrol were worse than others. What happens is that the lighter compounds in the petrol evaporate and stop the valves at the top of the pump from doing their job properly. It was particularly bad when going slowly or when stuck in a traffic jam and just after filling up when the heat had soaked through to the pump.

This had me going for months, I replaced the pump three times and a lot of the ignition system (people telling me it was the coil/leads etc). All wasted effort!

In the end I replaced the mech pump with a Facet fuel pump and I removed the mech pump altogether. I put the pump on a small bracket near the tank (under the passenger seat). You need the low pressure Facet pump FACET Solid State Fuel Pump 40105 3 0-4 5psi I also fitted a pressure reducer - you could probably get away without one but if your carb is a bit worn it may start to over-fuel (I set mine at 2.5psi). Don't be tempted by the cheap Chinese copy pumps on ebay - they self destruct after a couple of weeks leaving you stranded!

Some people keep the mech pump in place and add the electric pump before the mech pump - I'd advise against that. If the diaphragm in the mech pump breaks then it will fill your sump with petrol and dilute the oil - not good!

You can wire it straight up to the ignition. However, as a safety feature I wired mine up with a relay that cuts the fuel pump while the oil light is on. This requires a bypass button for starting. The benefits here are that if you roll the car then the oil light will come on an cut the fuel plus it makes it difficult to start if you don't know where the button is.

D

Good info, thanks.

Thanks for your replies and information everybody. I would not have been able to come along so far with this project without your help.

Today I made a few visits to local mechanics and got a funny but possibly functional piece of advice which I will share:

"filling a sock with sand and soaking it in cold water and placing it around the pump before any major trip to keep the temperature down".

He wasn't a mechanic but he said he knew them landivers like his own kids. I do not know if it will hold in a long trip but if it did I will post an update in case anyone was interested.

An after thought :
Dominic that makes one hell of anti-theft device as well, especially if button is designed like something that no one would possibly associate with an electrical switch.

Not sure the sock thing will work for too long, it will all still heat up in the end. Worth a try though!

It's not the best anti-theft, it only works if the carb is empty! It fooled me a couple of times though...

My understanding is that the 2.5 was fitted with an electric pump from the factory, maybe yours has been changed and someone has fitted a 2,25 pump, which i'm told can't keep up with the carb.

id be worrying about mpg if that was the case

Like James says, the mech pumps when working should be ok. They're identical to the ones on a lot of older commercials - my 45 seater coach has the same pump and it manages to keep up with that! I'm fairly sure 90's and 110's had mech pumps on 2.5 petrols, they might not have had the sedimenter though - I suspect the sedimenter is part of the problem with vapour lock. When the petrol in there gets hot then even if only a little of the additives/ethanol evaporates it would cause enough gas to (b)lock the valves.

I have been trying to find the spec for this truck (1985 Santana Especial 88) without much success so I really can't say if the mechanical pump was original or not.
It is a frankenstein of trucks, so many things on it are different than what one would expect from a series 3 of same period (roof, interior, lights, ....).

I did a 45 miles stretch today to test the sock theory. The cold water will evaporate very quickly and what remains is the sand in the sock around the pump. In case of mine it is right next to the engine and pretty hot, so how much of an insulation that is I can't say. I will experiment with different cooling methods on longer trips and if anything useful came up I will share gladly. Deep thanks to everyone from yours truly.