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MG Midget and Sprite Technical - Fuel filter for 1275cc

Morning,

I am back from a lovely weekend in East Anglia with the midget, 350miles, which almost finished half way through...

While driving the Midget on Saturday, she suddenly behave like she was running out of fuel (but she had)... I stopped on the side and checked the fuel lines at carb: no pressure. Check the voltage at the pump: 12V. I noticed that when removing and putting back the 12V connector, I could hear (only) one "click" from the pump. Strangely enough, I could still start the car, but she would stall if I didn't keep her in rev.

As some local nicely stopped to help me, I felt motivated to continue investigation and try to avoid road assistance! I removed the fuel pump from the car and tried it by directly connecting it to the battery: it ran perfectly! Back in its position: lot of "clicks", pressure back, car driving well again!

No need to say that I am curious to get your feedback and ideas, and I would like to improve the car to avoid this from happening again...

My main conclusion is contamination in the fuel, which I could easily improve by installing a fuel filter:
= Which one do you recommend ?
= Why it is usually in the engine bay ?
= I would prefer to install it before the pump: any advise on this ? Where to fix it ?

Thanks !

(PS: if they would ever read it, thanks a lot to the 2 locals who stopped to help me ! And to my navigator for her patience and ability to hold screwdriver like no-one ;) )



CH Hamon

Its unlikely to be contamination if there was no fuel coming through at the carb - unless it was completely blocked - again unlikely given that it started working again.
Sounds like it was given enough knocks during the removal process to jolt it back into life
Service the pump or replace it - I use a Huco 133000 every time.
S G Macfarlane

Cedric,
there could be many causes.

I'm not sure what you mean by no pressure at fuel lines at carbs - do you mean no petrol was get through and if so which hose, to carbs/between carbs/both.

It could be a blockage, (piss-poor rubber?) fuel hoses breaking down internally or in the solid pipe from or in the tank or to/from the pump. (Or the pump stops and is intermittent perhaps).

As with all electrics on the car the wires and connections need to be clean secure and protected, including the earth.

I cannot stand an unreliable fuel pump so fitted a Hardi (QH) electronic when I first got my Midget over 12 years ago, fit and forget.

One click could mean the pump has the fuel to the blockage.

A fuel filter will do nothing to clear an existing blockage other than to capture it if it breaks free and is before the filter.

I use a Mann WK 32, as it's small and inexpensive, in the engine bay just before the supply to both carbs. As filter is see-through I can very quickly and easily see if the fuel has made it that far without getting my hands dirty and it gives quick visual reassurance every time I lift the bonnet.

As usual more information would help.
Nigel Atkins

Forgot the photo, of pump, sorry could not find one of filter.



Nigel Atkins

Cedric,

is it an SU fuel pump? I suspect it may be because you refer to it clicking.
If it worked after you took it off, it may be the points inside the pump need cleaning or replacing.
Should it happen again when you're out on the road, give the pump a sharp tap that's known to get it pumping again.
Jeremy MkIII

Jeremy,
I think the clicking is also to do with the pump filling the system as my Hardi electronic clicks too.

That it continued to do so told me something was wrong recently, and the following smell of petrol. An ancient flexi-hose from the pump or ethanol striking again, you decide. :)
Nigel Atkins

Cedric,
sorry I forgot to put - depending on what existing pump or set up you have you might already have a filter in the pump or at the pump so you could check those for blockages.

I've never that I can recall had an extra fuel filter at or before the pump in now hundreds of thousands of miles in classics including MGs and have never had fuel blockages - leaks, yes, blockags, no.

Nigel Atkins

Never mind the fuel problem, how the devil did you get your young lady to get out and get under? I've never managed that in 45 years of being with her!
Mike Howlett

Mike, those are Cedric legs!!

But on looking at the photo again I hope that jack was out just clearing boot space and wasn't used and certainly not whilst anyone was under the car. Those jacks are unstable at the best of times and that layby seems to have a fair camber to it.

I know for certain you can get to the pump with the car on sitting the ground from the back of the car as I had to do it to change that ancient hose recently.
Nigel Atkins

Most likely just the fuel pump itself sticking. Very common problem with the original, non-electronic su pumps. Normal roadside "cure" is to reach under the back of the car and give the pump a thump with a hammer, block of wood, half brick or anything else within reach. Usually the pump then ticks wildly for a few seconds as it refills the pipework and carbs, and then off you go again.

Mine did it repeatedly on one journey to the point that I could aim a blow at the pump with a wheel brace, just by opening the car door and leaning out a bit - not whilst still moving though!

Take the pump off, remove the cover cap and clean the electric contacts and springs inside with a few squirts of carb cleaner. You may even be able to do this much without removing the pump from the car, depending on which way the cap end is facing.
GuyW

My brother had a Hardi pump (with points) on his MGB. That would fail in the energised state, as the points weren’t flicking open. Switching the ignition off and back on got it running again.

Replaced it with an SU.
Dave O'Neill 2

Thanks for all those feedbacks so fast :) To give you more details :
- It is an SU Pump, installed somewhere in 2000-ish by the PO. I will check again the invoice tonight
- At the beginning, I disconnected the "main fuel line" arriving in the engine bay, just before going to the carbs, put the ignition ON, and check if fuel was getting out (putting it in sealed bag, taking care of the exhaust....). Just the fuel which was already in the line went out, no more.
- It is my legs :) The person behind is the first local who stopped to help. I am not that old, just miss some hairs... ;p The fuel pump bracket has a “recent” fixing: screw on one side, nut on the other one: she was holding the screw while I was removing the nut from underneath. “Sadly”, she is taking the picture, so can’t be on it :P

So you think more of weakness of the pump as contamination…
=> Would you feel confident to keep it after cleaning it, or I should still replace it ?
=> Nobody in favour of the filter before the pump ?
CH Hamon

Cedric's legs - whoops!!! I suppose that living in Scotland for so long means that I rarely see men in shorts so I assume a bare leg must be female. Still, that's a good shapely leg....
Mike Howlett

I never did trust those jack's !
It's quite possible for the jacking point tube to collapse upwards through the cill.
GuyW

Cedric,
(Dave) the (QH) Hardi type pump I have is (AFAIK) electronic without points.

From what I have read, and experienced with parts myself, SU Burlen products and parts are not the same quality that they once where.

Personally I would not pay extra for a SU label or would I buy a pump with points, this thread may or may not back my view up (new SU points pump playing up) and I bet your girlfriend would agree with me.

As Guy has put it may be worth looking at but personally I would pass it on to someone who enjoys stopping to lean out of the car and hit it, I prefer not to stop and not have to think or worry about the fuel pump, very joyless and unmacho I know.

I thought I had suggested this but in case not - for sorting electric problems (preferably at home when it is warm and dry) with a kit consisting of a length of twin cable long enough to reach from the fitted car battery to easily reach the furthest point required, perhaps a recycled vacuum or lawnmower lead. At both ends have connectors and made up a collection of short links with various sort of connectors to cover what you could possible connect to, also have suitable clamps to put on to the battery. This kit then means you can run a direct supply and earth from the battery, without disturbing it, to most electrical items to test them direct off the battery eliminating other connectors and switches.

Yes, the ladies like to take photos against instead of with the sun.

I would also get that jack to someone who wants one to made up the kit for a show car. (ETA: Guy and I do agree on some things).

Small accidents can happen in a fraction of a second but might give a lifetime of regret and often the more testosterone or macho mindset the more accidents happen. Unfortunately as you get older the testosterone might reduce but macho mindset remains.
Nigel Atkins

" I suppose that living in Scotland for so long means that I rarely see men in shorts so I assume a bare leg must be female"

What about men in kilts?
Dave O'Neill 2

Men in kilts don't lie down with their legs in the air!

Well not at this time of the year.
GuyW

In any case, men in kilts wear long socks. When my older son got married he had a bouncy castle at the reception and all the young guys had a go in it..... wearing kilts. Not good.
Mike Howlett

Before you bin the pump... I fitted a solid state electronic conversion (from Burlen)to my existing SU pump because it did exactly what you described, and it's never missed a beat since. If you periodically clean the points or service it, it should run reliably anyway, but I can't fault the solid state conversion at all. It still clicks in the same way, I've still kept the original pump with the car but have no points to worry about.

http://sucarb.co.uk/su-fuel-pumps-spares/electronic-conversion-kits.html
R Cohen

For the same price as the conversion you can buy a new Hardi pump and wrap the flimsy SU label around it.
Nigel Atkins

The original SU pump is very reliable and will run for about 12 – 15 years of normal use, or much longer if you only use your car on Sundays.
Once it starts to falter, overhaul it and it will be good for another 12 – 15 years.

The SU pump only ever had one problem – that when it did get old and tired and falter, it would respond to a tap (which eventually becomes a hit as it gets worse) and start working again. Thus, people would not get around to overhauling it (just give it another hit), yet mutter about the unreliability (hit it again) of it every time they had to crawl under the car and HIT IT. So was born one of the great urban motoring myths! Of course it was unreliable then – it was worn out! It’s a bit like running tyres worn through to the cords and wondering why you lose the air so often!

A new set of points and occasionally a new diaphragm (check by how flexible it is, there should be no diference between the fuel contact area and the outer edge where it is clamped between the pump body and base), all correctly adjusted as per the workshop manual, and it will run happily for another 12 – 15 years. As simple as that!

The adjustment is critical

PS Nigel, I have to say I disagree with you about the quality of current SU parts. We overhaul a lot of worn carbs and fuel pumps and I don't recall a single quality issue. At worst, very rare.
Paul Walbran

Here's a compilation of the key WSM adjustement instructions which I include with every set of new points we supply. (Sorry, hastily done camera shot as we only have it in pdf form which wouldn't upload)

A bi-directional diode also makes an excellent spark suppressor, shunting enything in excess of its nominated voltage across the points. We use 20V-25V.

The only comment I would make on electronic units is that I have seen them fail, when they do so it is without warning and they don't respond to the interim tap on the body, so a roadside fix as per Cedric's fine photo is not possible.



Paul Walbran

Paul,

Nicely put, I think the SU pumps of old got a bad reputation and was undeserved because considering the mileage they covered between problems they were actually very good items. I still recall having to tap a friends Mini countryman SU pump to get it running after a night out.
David Billington

I fund back the invoice for the pump :)

It is from MGOC, in....2003 ! And approximately 4 000 miles ago.
It says "SU 214 - Fuel Pump 1098+1275 OE"

I think I will go for a good service as you all described it, and use the "HIT" solution until then :p


For the jack, i was expecting some comments, and you are right. I didn't lift the car a lot, just a bit to make moving under easier, but still, I should have had better to use... I think I will leave an axle stand in the car, just in case (I am still in the phase where I carry a lot of tools in the trunk :) )

Thanks again for your wise comments :)
CH Hamon

Paul,
believe it or not I'm totally with you, nothing wrong with overhauling the pump every 12 years, before it fails. That does require you knowing about the pump's history of course.

And I agree you should not give something the blame for your laziness or procrastination.

And I very much want spares part to be of good quality.

For SU I was commenting on reports from others I've seen and the parts I've recently ordered.

I have three sets, one from the recent order, another from when the carbs were brand new 9 years ago and from s/h carbs of unknown age but look a lot older. Even to me poor eyes I can see a difference in construction/assembly between the three sets and with the older ones having their part number on them and the other two sets don't, a small point I know but perhaps a pointer to a difference of what's expected.

I thought SU supplied all the parts but I might be wrong, is there another manufacturer/supplier of SU parts.

Problems with float bowls, needles and seats and SU electronic pumps come to mind at this moment.
Nigel Atkins

Yes, there are other manufacturers of parts for SU carbs and pumps, and there are quality/fit issues with them.
Which is why I have stuck with genuine.
One really bad example is a pump diaphragm with a different thread where it should crew into the points. Which it couldn't.
I've also found carb needles not to profile, inferior needle valves, and numerous other issues with copy parts (sold under OE number)
The only failure I have seen with genuine has been an electronic pump, ironically enough.
Paul Walbran

Once more, I was wised to post here before doing what I intended to do... This prove that you were all right, once more, no ? :)


CH Hamon

I used emery clothe to rub them, then petrol to clean them: is that alright ? :)

Still, one was difficult to get properly, as it look like having a "small hole" on it. Couldn't get it 100% off, or I would have no more contact point...
=> What do you think of this ? Sorry for bad picture...

To finish, should the inlet/outlet port of the pump face the differential, or the wheel ? I have doubt on the PO set-up...


CH Hamon

You might want to check it running with the cover off and look for arcing at the points. If you have a meter with a capacitance range you could test the capacitor to see if it's OK. If bad you'll get arcing and points damage.
David Billington

Cedric,
the pump the outlet goes vertically above the inlet port, with the inlet and outlet horizontal.

Make sure your live and earth wires and connection are in good condition and are clean, secure and protected.

I don't know where the breather hoses go as my pump doesn't need them.

I fitted a fresh petrol filter on Saturday so if you want I can post a photo of that and you'll be able to see it as it's still clean (so far).
Nigel Atkins

Cedric,
just a point of interest to me, as I have recently learnt from Paul (thank you) that many "SU" parts are not always from SU themselves is your pump actually from SU with the SU label or marking on it?
Nigel Atkins

"the pump the outlet goes vertically above the inlet port, with the inlet and outlet horizontal."
Yes, I did that, as it is well explained in the workshop manual. Might be silly question, but it doesn't say "which way around": should the outlet/inlet face the differential, or face the inside of the wheel arch ?

"Make sure your live and earth wires and connection are in good condition and are clean, secure and protected."
Did that too :)

"I don't know where the breather hoses go as my pump doesn't need them."
I didn't really get how this work.... I have a nipple close to the diaphragm, and a "tube" at the back of the pump, but only one pipe under the car... So didn't really understood what they are for, expect they communicate between both. Did have a look on Moss diagram, and my car is different... Might have been "simplified"...

"is your pump actually from SU with the SU label or marking on it?"
I can only remember having "SU tape" and a stainless steel plate with written "AUF 214" on it. Does it prove it is a real SU or not? Don't know
CH Hamon

Cedric,
do I detect the hint of English sarcasm, if so well done, and I bet we have more varieties than in France. :)

I must admit that I thought the SU pumps had the fuel connectors both facing the same way. I would have thought at least one of the connectors would be marked in or out. (ETA: yes they are)

Sorry but I do not know the original fitting position of the pump and bracket. I do not think it matters as such which way they point as the pump and bracket could be fitted in different ways as long as fitted as per instructions.

Looking online, if the SU AUF214 is fitted with fuel connectors facing the fuel tank then the outlet at the top faces the wheel and the inlet at the bottom faces the diff. (see photo).

The breather(s) go into the boot I think but as long as they are protected from blocking I do not think that matters, but might be wrong.

Yes, to me, with the given information, your pump sounds like it is a SU - so you could order a new set of points and a repair kit if you want.



Nigel Atkins

Sorry photo for i-phone users.



Nigel Atkins

You can of course rotate the fuel connectors any way you like, to get nicely positioned fuel lines. The only requirement is that the outlet is at the top so that it self bleeds any air out of the pump.
GuyW

Yes Nigel, they are not too expensive... http://sucarb.co.uk/su-fuel-pumps-spares/points/twin-point-rocker-assembly-and-blade.html
Need 5 replacment to arrive to same cost as implementing electronic... I will stick to contact points, don't think/hope I will have to change them more than 5 times :P

Thanks Guy for confirming. I put the pump facing the diff, makes shorter fuel lines and less complex path
CH Hamon

Sorry Cedric, I have just realised I totally misunderstood your question about which way the pump faces (I thought you meant the individual nozzles as your bracket was fitted a different way perhaps), genuine mistake/misunderstanding/brain-fade on my part.

I can understand your repair but what about a full repair kit including points -
http://sucarb.co.uk/su-fuel-pumps-spares/single-hp-pumps-kits/fuel-pump-repair-kit-11894.html
Nigel Atkins

Guy,
so I don't get this wrong again (unless I forget) do I take it you mean the two nozzles can be turned so they both point in the same direction, by removing that black end locking(?) ring, turning to new position and replacing black locking(?) ring?

If so it looks like I could have done the same on the Hardi pump when I fitted it had I known, I took it as the positions were set and followed the previous installation, wonder if I should try turning the nozzle that's been set for 12 years, when I replace the other ancient rubber hose to the pump?

Nigel Atkins

Yes Nigel, the 2 screws holding the steel ring can be slackened or removed and the black plastic fuel pipe connections rotated. But they do get a bit set in their ways and being fairly fragile it is easy to damage them if too much force is used when they are stuck.

I have no idea about your particular Hardi pump. I do happen to have one but on mine the metal pipe connectors on it are screwed into the main body and their orientation cannot be altered.
GuyW

"Sorry Cedric, I have just realised I totally misunderstood your question about which way the pump faces"
= No problem Nigel, it can be a lot of things: my English, my mechanical (un)competences,... :)

"I can understand your repair but what about a full repair kit including points"
= Price ? :) Pump looks fine, now with cleaned points, so I think she is OK for few years again ? :)

About orientation, I meant the pump itself and not the nozzles/ports. But it might make sense to move them too, as now I have the OUTLET facing the tank and the INLET facing the engine... Still better than previous, but might change the nozzles/port orientation at the next contact points clean-up :)



CH Hamon

Thanks Guy.

My Hardi pump is the same as in the photo I posted earlier, I've now looked it up and the nozzles can be rotated 220 degrees, I'd guess the locking plate has angled cut outs as at one point is stamped 'top' 'oben'/(above). I've emailed Hardi in Germany to see what they say about trying to move them after all this time.-
https://www.hardi-automotive.com/wp-content/uploads/DB13312.pdf

When I put the new fuel tank in I thought about tidying the flexi-hoses up a bit but then got distracted by the fact the new tank was the same make as the old tank but had a printed label for the model number rather than embossed as on the old tank, and the fact that the old tank was only about 10 years old, then the new tank just didn't quite fit over one of the captive threads without filing.

I can't really remember fitting the Hardi pump, other than marking up the electric connections on the pump with insulating tape as the markings weren't easy to see, I think I just copied the previous installation.
Nigel Atkins

Cedric,
it was definitely me reading it wrong. Once I saw my mistake it was obvious, same with being able to turn the nozzles once pointed out.

And after thinking about it I remembered the pump bracket goes on to IIRC two captive threaded fixings on the body so if the car has those at least one orientation is fixed.

The nozzles on mine point IIRC inlet to tank and outlet to carbs but the copper supply pipes have been left overlong making one flexi-hose shorter than usual but the other flexi-hose is longer than usual to get a softer bend. I intended to tidy previously and might when I replace the fuel tank sender seal if I don't get fed up before the end of the work - or I could supervise you doing the work as practice for yours? :)

Nigel Atkins

Here is a scan its very similar to the diagram in the Moss parts book - Fuel system page 148 in the copy I have but has a slightly different presentation .

With the brackets and hoses as shown the electric cap end faces the wheel (as does mine).




richard b

Here is my pump set up.

Now I've seen the pic I need to have a go derusting the brackets etc - note to self avoid going to Aldons Rolling road in the snow !


richard b

Here is a pic of the pump vents in my boot - just below the rear bulkhead panel above the pump. I think they should both be the 'tee' type fitting like the one on the right.

One is from the pump chamber and the other from the contact breaker area.

R.


richard b

I always thought it odd to vent petrol fumes into the boot. But I can only presume that this is preferable to venting them under the car where they might get excited by sparks from the pump contact sets.
GuyW

Hopefully not fumes !
I assumed it was only the air being moved by the various bits of plungers flying up and down etc ?
richard b

Rich,
thanks for the illustration makes it a lot clearer and explains the P-clip size with the various sheathing.

Venting to under the boot carpet seems odd but so did the elaborate venting pipes to me.

With the photo of your two venting tees (well one and a custom elbow) I had to go and look in the boot of my Midget as I was sure the two tees were a lot further apart in my boot. I found there was only (ever) one tee, (poor memory again) and it wasn't in the same location as either of yours so I assume (risky) that it was added in by a PO but I can't remember it being used on the previous pump.

I also appreciate your photo of the pump flexi-hoses as you have a similar crossover look as I have, despite me going for concours curves. Mind the rust on the bracket is a disgrace, I could eat my dinner off of mine.
Nigel Atkins

“Hopefully not fumes !
I assumed it was only the air being moved by the various bits of plungers flying up and down etc ?”

That is correct. The one vent is from the non-fuel side of the diaphragm, the other from the cap. Shouldn’t be any fumes there.
Dave O'Neill 2

So if they are not fumes, just air, then why not just discharge it through the pump vent where it is, under the car?
GuyW

Prevent blockage? It was what I wondered about too, and, under, the boot carpet(?) but these old designs seem almost pre-Victorian or steam age technology, fine items though they are. :)
Nigel Atkins

OK, maybe the point is this. If its a breather to compensate for "air being moved by the various bits of plungers flying up and down" and possibly air pressure and humidity changes, then as a breather it might both expel air and draw it in.

So the longer pipe into the boot area would ensure that salt laden puddle splashes from under the car don't get sucked in through the vent which would rapidly hasten corrosion or electrical shorting of the moving points mechanism. Venting into the boot via a longer pipe would hopefully reduce the possibility of drawing in damp comtaminated air.
GuyW

There is definitely no 15min job on those cars :)

Thanks for explaining and showing the fuel pump layout and installation, much more clear to me know :)
I was right to assume that mine was not logical, and you will be able to give me "the good one" (and why :P) ;)
CH Hamon

This thread was discussed between 24/09/2019 and 09/10/2019

MG Midget and Sprite Technical index

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