Possible fuel pump problem

[elvimto]

I drove my car today and it ran really well fastest road speed about 55 which was the limit and about a 12 mile drive. Then the car cut out died pulled over and tried to start no joy I waited abit then it fired back up and I managed to get it moving this happened four times in the last few miles to get home. I have an electric fuel pump from LD Parts which is very new and on checking it the pump was very hot to touch. I cooled it with a cold pack and the car started up and I made it home. I am getting 12.5 volts at the pump connections so the supply is good I have other checks to make but it does seem to be fuel starvation is anybody running one of these pumps and do they run hot. I looked at Peters web site and don't see a email for him anyone have that?

Stuart

[barkerwilliams]

Sales@ldpart.co.uk

Peter responds quickly. Does pump run continuously, it shouldn't?

Alan

[barkerwilliams]

Stuart,

Thinking more of your problem I would check the pump connection to the fuel tank pipework. The pump creates a vacuum to lift the fuel up to the pump where it pushes it to the carbs. A slight vacuum leak on the pump fitting will prevent the pump reaching pressure and starve the engine of fuel and running continuously trying to reach pressure will cause it to overheat. As it is a vacuum fitting it never leaks fuel so is not easy to spot


Incidentally if working on the pump put a rag below, blocking the void between the panel and floor as o rings and bolts drop under the tank with consumate ease!

Alan

[Dean]

Hi I am not knocking ld parts but I have had two of pumps mentioned the first had the continued pumping when ignition on which he listened too over the phone and he sent a new one straight away, the second was still no different and I to had the fuel starvation every now and then exactly what you described, I have now gone back to the modern su pump and its now perfect stops ticking when ignition is on and no problems at all

[mjheathcote]

Stuart,

Thinking more of your problem I would check the pump connection to the fuel tank pipework. The pump creates a vacuum to lift the fuel up to the pump where it pushes it to the carbs. A slight vacuum leak on the pump fitting will prevent the pump reaching pressure and starve the engine of fuel and running continuously trying to reach pressure will cause it to overheat. As it is a vacuum fitting it never leaks fuel so is not easy to spot


Incidentally if working on the pump put a rag below, blocking the void between the panel and floor as o rings and bolts drop under the tank with consumate ease!

Alan

Maybe not this particular problem but I've had this problem of old hard fuel pipe causing a vacuum leak on fuel suction. Was a problem for a while with insufficient fuel delivery when on constant load.

[elvimto]

Thank you for the replies I have sent a note to Peter and will see what he says. I will also check the fuel system The car does not used a lot but It has been quite reliable and the pump has been in place for a little over a year. The reason I suspect the pump is not working is I had the same running out of fuel situation before its different from just cutting out but I need to be solid the traffic is nuts here and the street speed limit is 45 most places and some drivers are not to attentive.

[trunt]

+1 on the pickup pipe - been there done that..

Another consideration on a federal car is the vent system, which is sealed up pretty tight. The only way for air to get in is via the long pipe from the charcoal canister in the engine bay. Should that block there is a possibility that the tank will come under negative pressure after a longish run, causing the pump to falter..

It’s unlikely but worth a quick check..

if you dare to do another run, a blockage would cause a rush of air when the filler is opened. Or maybe blow or suck air down the pipe from the engine bay, with the filler open of course to make sure it’s clear.

Terry

[elvimto]

I had an email from Peter and am going to look at the system my canister and the lines have all been serviced I opened the canister up and re energized the charcoal ok I burned of the vapor but joking aside I put the car away until the week end and will visit then.

[richardthestag]

+1 on the pickup pipe - been there done that..

Another consideration on a federal car is the vent system, which is sealed up pretty tight. The only way for air to get in is via the long pipe from the charcoal canister in the engine bay. Should that block there is a possibility that the tank will come under negative pressure after a longish run, causing the pump to falter..

It’s unlikely but worth a quick check..

if you dare to do another run, a blockage would cause a rush of air when the filler is opened. Or maybe blow or suck air down the pipe from the engine bay, with the filler open of course to make sure it’s clear.

Terry

Slight off topic

Can all the Federal vent and emissions "crap" not be removed and the car reverted back to a simpler and more reliable European / RotW system? Or is it still a requirement of the US version of our MoT?

Here any Stag first used pre August 1975 is a subjected to a "visual" test on exhaust emissions. Any stag August 1975 onwards needs to be 4.5co which to be frank is easy with a well serviced engine.

Any sign of dripping fuel though is an instant fail, a stink of fuel in or around the tank would get a tester suspicious.

Might make the fuel delivery issue a lot easier to fix if all the extra pipework and cannisters etc were in a box on a shelf in the garage.

[Roy_S]

Mine always smells of petrol in the boot, thought that was Stag territory marking.......
I spent ages in getting the banjo bolts to seal properly, and have replaced all the pipes with new fuel specific pipe, but they still have a petrol smell to them like they sweat. No leaks or anything, pump clicks on ignition and stops with no fuel drips anywhere.
I leave the boot a little open in the garage to vent, but as the garage is part of the house you can smell this at times, might have the look at replacing the fuel pipe again.

[trunt]

I’m not sure as it depends on which State you are in. Some are similar to UK in that local garages are licensed test centres and do the “MOT” testing its fairly thorough but not as tough as U.K.. Others like my state of DE have state test centres and basically just test brake operation, light operation wiper operation and emissions, they don’t even check the tyres, the bonnet is not opened and the car is not inspected underneath.

The fuel side of emissions on the Stag are not that complicated really, (OK the mk 1 has a rats nest in the boot) but basically all fuel fumes are directed to the charcoal canister, The tank has that hose to the canister instead of to the floor, the carbs vent to the canister instead of the floor, The canister(s) are vented to the engine breathing, so the carbs suck up all the fumes, any excess is sent out to atmosphere via the charcoal. None of that affects the emissions out of the tailpipe. As an aside this goes a long way to prevent any ingress of water vapour to the fuel system, a plus when you run E10 fuel as I do. I left it all in place, it does no harm and looks correct.

The part that does affect emissions is the timing. The vacuum retarding of ignition at idle reduces emissions but introduces other problems. Firstly it runs hot, later cars actually had a thermostat in the radiator that if it gets too hot removed the retard, causing it to run cooler plus idle a bit faster to speed up the fan - Brilliant! The other problem was running on. I’m not sure why or if it actually did that but they added a “run on” valve that as you turn the engine off operates for a short time using manifold vacuum to purge the charcoal canister. My best theory is that it applies a vacuum to the carb float chambers, cutting off fuel supply to the jets, Or it had nothing to do with running on, just emissions.
All of that stuff I removed and converted to a vacuum advance. My experience is that a well tuned engine can meet the early emissions regulations regardless. Though my highly tuned TR Needed to be retarded a tad to make it through.


Terry

[elvimto]

Just an update I had other things that have got in the way but I did look out a few of my spare old pumps including one I got from LD part If time permits I am going to bench test some of these and see if they work and will fit one to the car also I am going to by pass the fuel regulator and give this a try. All my emission system is still fitted and working no testing since the car is pre 1975. The ROM says the pump should be AUF 306 but Burlen does not show that one has this been upgraded anyone know?

[Roy_S]

My fuel pump which is the mechanical type wouldn't work when I started to get it read for the road again. When I took the pump apart I found the diaphram was stuck solid with old fuel residue, the valves were stuck shut. Once cleaned and put back togeher it was fine, ticks away like an old clock in the boot

[singapore stag]

I have a spare pump in the boot ' just in case ' . I know its not original but I trust these German metal bodied electronic ones better then the points type which have a mind of their own,

s-l300.jpg

[elvimto]

Do you have a part number or a supplier? I am in the process of going through this problem trying to get a pump going and finding out what the problem is. It possibly is that the pump is overheating due to being overloaded. The set pressure of the pump I have is 2.4 psi so I will eliminate the regulator first. I am making a test set up on the bench to run them going to use thinner which is less volatile than gas or petrol for a pumping fluid.