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MG MGA - Fuel Pump

Hello all!

Its been a minute. I hope this finds you all safe and healthy.

I am finally facing the need to fix my fuel pump.

Here are some questions, some may be simpleminded

1) Do I tell if my pump is solid state or points without removing it?

2) If its a points system can the points and condenser be fixed in place?

3) If I have to remove it, how do I do so without getting gasoline everywhere.

Thanks as always,

Tysen
Tysen McCarthy

1) take the cap off

2) difficult if not impossible

3) disconnect the suction line at pump using drip pan, then run engine to dry.

Art (never having done 2 or 3!)
Art Pearse

Hi Tysen

Nice to hear from you again.

You will get only a little fuel leakage from the lines, not the whole tank.

It is too restricted in there to do the pump points in situ. Best thing is to remove the pipes at the pump and take the pump out and fix it on the bench. If it is fitted as originally installed, you should be able to get at the pipe unions from above through the battery cover.

Fixing and testing on the bench is easy, but before you take it out, try taking off the cap, and run some wet and dry between the point surfaces and see if that brings it back to life. Often that works.

If it doesn't I can highly recommend the SU electronic points version - mine has been in for years (15 or even more more?) without any issue whatsoever

Dominic
Dominic Clancy

Thank you both!

I am experiencing a generational shift after all these years of haunting here.

My now 18 y.o. is currently under the car taking the cap off and will report back with photos.

This is nice.
Tysen McCarthy

Follow up question. My son confirmed that the existing unit is a solid state unit.

In your experience do these units get "glitchy" or do they just die.

My symptoms seem like intermittent reduced fuel flow.
Tysen McCarthy

Like all solid state devices, if they die, they usually die fatally. That's why I have always stayed away from electronic fuel pumps.
However, if you have intermittent fuel flow, check that the filter in the pump or inline isn't clogged and that all of the fuel lines unions are tight.
Lew Palmer

If it is the Burlen type electronic pump there is an adjustment on the hall effect sensor which can restore normal operation.

In my experience of these pumps do go out of adjustment - the last time I had to tweak one was under the V8 in France lying in a puddle in the pouring rain ...
Chris at Octarine Services

Blimey it's fuel pumps everywhere on the BBS today!

Tysen,
as I and others have put in other MGA threads, if you can get Hardi electronic fuel pumps in the USA or their equivalent in design and quality that's the way to go - fit and forget, not fit and fart about (last bit just me).

Hardi - http://www.hardi-automotive.com/en/products/fuel-pumps/

I'm asking for commission now!
Nigel Atkins

Follow on question.

As part of this problem we disassembled the float bowls and sent some carb cleaner up the grose jet.

Afterward I find that they are a little stick for the first touch against them and then they flow easily.

Is that common?

Also, what is the trick to removing them. I can't get a socket down there and there is not enough lateral room for a wrench.

(Nigel I found a US distributor, you can reach out to them for the commission)

https://www.bpnorthwest.com/fuel-pump-electronic-dual-polarity-bn1-bn4-mg-tf-mga-mgb-to-64.html?gclid=EAIaIQobChMIxaKLtIf46QIVkeeGCh3W0gNfEAQYAyABEgItCPD_BwE



Tysen McCarthy

Tysen,
first thank you for finding a Hardi pump supplier, I've seen this company before so will note all their future sales to MGA owners. :)

You won't get a socket down there as the float is in the way, doing so might bend the float arm so that the valve (needle and seat) open too soon or late because the float aint at it's required level.

All ease stuff, clean and lubricate the float pin and remove it, it may have to be tapped out in one direction only, get a young pair of eyes to look (and them do the work if possible "all this will be yours one day" you lie, spend it all). :)

A slim 1/4" drive socket of a size I've forgotten (7/32"? will fit well if not exact size?) to take the seat out to fully clean the area behind.

That is a Groose jet, not the prefered option of Burlen SU but if it works just clean it.

Have a look at the (John Twist) University Motors videos channel for all the relevant vids that also relate to MGA and Barney Gaylord's excellent web site (probably tell you the correct size of socket for seat too).

SU Burlen - loads of info (but very poor search facility it can't even find some of the part numbers it shows!) - http://sucarb.co.uk/

(See vids below) - JT's 200+ vids - http://www.youtube.com/user/Universitymotorsltd/videos

Barney Gaylord's site - http://mgaguru.com/mgtech/

Just thre of the vids relating to MGA matters -
222 MG SU Carburetters: Setting the Float Height (needle & seat comparison) - http://www.youtube.com/watch?v=82YNx-RkGNI

232 MG Carburetter Needles and Seats (odd sizes) - http://www.youtube.com/watch?v=pVX_JClyeDQ

(MGA) 29 SU H-Type Carburetters (MGA) - http://www.youtube.com/watch?v=GHNlT5yHDxk

Have these two, er, too -
44 Secrets of the SU Carburettor Part 1 of 2 - http://www.youtube.com/watch?v=7GRAcqDySog

43 Secrets of the SU Part 2 of 2 - http://www.youtube.com/watch?v=60Bj_2cZQnc

There are still many other JT vids there relevant to MGA matters.

If you didn't before, now you definitely know more than me on it, not difficult though.
Nigel Atkins

Nigel. You should be tucked up in bed at 1 am!
Dominic Clancy

Dominic,
I think what probably happened is that Nigel began looking up all that info and searching out all those links at about 8.00 pm, but by the time he had finished, it was 1.30 am! :^)

Great reply, Nigel, you have given Tysen hours of stuff to study.

Colyn
Colyn Firth

The staff didn't find me until 1:15, I sneaked out during their break. hehehe

The carbs hyperlinks are on a Word.doc I just have to try to remember which are relevant and then check they still work.

I've quite a few notes I just copy&paste from but then spend ages altering them to fit the post and in doing so end up losing most if not all comprehension in them.

What did take me a search was for the JT video that mentioned adjusting the float height, when I eventually found it I discovered it was the very first one I put in the post, called '222 MG SU Carburetters: Setting the Float Height', which I'd just looked at as my previously added '(needle & seat comparison)'.

The medication must have kicked in before then so a good job they found me and locked me back up in my room.
Nigel Atkins

Well thank you indeed Nigel!

Fantastic!

I had the good fortune to visit John's shop while we drove past by on vacation. He lives about 2 hrs due west from my home right on the way to the shore. 2 weeks later on the way back home from vacation I bought my MGA from him. 15 years ago yesterday.

I don't think of looking at his YouTube series nearly often enough.

Barney's site is always a go to.

Frankly I often stop here first just to talk to you all.

I'll keep you posted on what I figured out.

I recently made the mistake of purchasing a 40 y.o. sailboat. Maggie Mae the MGA is feeling a bit cheated on. She's throwing me these fuel problems and then yesterday I found a big puddle of hydraulic fuel where the steering gaiter split...I think....I haven't really dug around yet.
Tysen McCarthy

We started the car back up after cleaning out the grose jets.

I gotta say the fuel pump ticked right through as it filled the float bowls.

Unfortunately I couldn't get the car to a good idle, lots of popping noises. Uneven

On a whim I decided to pull the front and rear plugs. This is what I found. That doesn't look like a fuel starvation problem to me. It looks almost like the opposite.

Could this be a result of a weak spark?

I have a pertronix ignitor coil installed. It only has 10,000 miles on it, though its 10 years old.



Tysen McCarthy

I never put too much by spark plug colour but those look bad.

They look sooted-up, dry black, and what's the rust coloured stuff? I'm not surprised it's not idling well.

Do you only drive the car short distances (less than 15-20 miles before stopping so not properly warming the engine) and then drive like a maiden aunt, have the choke out a lot?

An average of 1,000 miles a year doesn't sound like a lot of use.

Have you got an oil cooler in a cold climate?

What makes you think you have a weak spark (it's got a lot of soot to get through with those plugs)?

Unless you think there something seriously wrong with your car I'd suggest you try fitting four brand new and recently purchased spark plugs (not used one rattling around in a tool box for decades like someone else recently) and drive the car, get the car (not just engine) fully warmed and fully operating and then give it the Italian tune-up (drive it hard and fast for a good few 10s of miles) and then pull over quickly switch the engine straight off and pull the plugs out there and then to see how they look. Caution as things will be hot. See what colour they are, then drive back at a sedate pace and see if there's a difference in plug colour when you get back home from the slow driving section.
Nigel Atkins

Oh, are your carb air filters clean, depending on which type you have the filter housing and particularly the filters themselves.
Nigel Atkins

Tysen
To me, those plugs look likes your mixture is way too rich. Why is the question.
When I first bought my MGA I had a similar problem. I discovered the choke levers were not returning so the choke was permanently on. Easy enough to check that
Graham V

Its probably worth a little more background

I did complete rebuild of the engine in 2008. I had a lot of help from many folks here and Barney and his web page. The rebuild included rebuilding the carburetors and some upgrades; ported and polished heads, enlarged pistons, moderately faster cam, etc.

Up until this year, following kids around prevented us from getting many miles under us.

I guess I’d characterize myself as a modestly sporty driver, though our trips tend to be short.

The plug are approximately 3 years old. (the rust is on the nut part and is caused by winter condensation, though replacing them is probably a fine idea)

The car has run very well up until last year. It started with a slight “hitch” in her step. If I goosed the throttle it disappeared.

Since I had replaced everything else, I thought maybe it was a fuel pump going bad.

Unfortunately, I ran out of time to really focus on it.
About a month ago we went out for a ride and the hitch had gotten much worse. To the point where I was confident that we were risking getting stuck on the road.

Recently it won’t even idle and or keep throttle up

So, to date;
• I took off the cap of the fuel pump and verified that it is solid state.
• I’ve checked the screen in the pump and cleaned it (it wasn’t bad)
• I’ve disassembled the float bowls to make sure they were filling
• Cleaned the grose jet and the screen in the top of the float bowls.
• The fuel pump ticked strongly to fill up the bowls (though I suppose the diaphragm may be stiff)
Car still won’t idle
Tysen McCarthy

To check the pump it's just a matter of disconnecting before the carbs and see how the flow is and measure the quantity issued over say 15 or 30 seconds.

As Graham has put always worth checking something mechanical isn't sticking or stuck, clean and lube often.

Could be your mixture set up.

I prefer to do a service or service check as a systematic method, turns up other stuff often too and if you've not serviced the whole car for a while then don't stop at just the engine and carbs (the two least important things on a car).

Most servicing boils down to clean and lube as well.

I know John Twist doesn't seem to like those Grose jets, whilst they're clean are they working properly.

I don't think the petrol pump or the Petronix would probably cause those plugs - but then I'm soon out of ideas!

Nigel Atkins

From all that's been said above my money is on choke levers not returning fully home. From my experience just running a bit rich with blackened plugs would not necessarily give the erratic idling/running. Chokes stuck out a bit is another ball game and would tie in with your symptoms.

Easy to check. With the choke lever fully home put your hand underneath each jet assembly in turn and push up. Any upward movement and that's your issue. On one occasion I had one of the choke lever arm return springs part company with similar symptoms.

I was warned off the later Grose jets. Not up to quality.


Steve
Steve Gyles

Of course there is the old very non PC joke here about the woman driver who had this problem and she thought the choke knob was pulled out to hang handbag on. Not relevant to this case though.

Paul
Paul Dean

As considered a stuck choke was part of the difficulty. The cotter pin that holds the linkages together was missing. That’s been fixed but the car won’t keep an idle.

The fuel pump is working fine. It pumped 16 oz in 30 seconds.

I will replace the spark plugs and give the carburetors another once over.

I am testing without the filters on right now so they aren’t the culprit.

Any other ideas?
Tysen McCarthy

Found It!

Arcing ground wire at ignition coil.
Tysen McCarthy

Well done, and thanks for reporting the outcome.

I hadn't seen your last post and was just about to reply could it be electric side then ('onest) as many 'carb problems' often seen to be, as only today I had part of a problem that might have originated from me knocking my dissy cap out of alignment without noticing.

But for your issue I'd still have put to start with checking the chain, tappets, points, plugs, timing mixture in that order.

I'm going to check the tappets on mine later today before I go back to the carbs everything was fine the other week with the car going very well and then it wasn't, but why I don't know yet. :)


Nigel Atkins

Tysen

Interesting about your cotter pin missing. I had very similar but it was the choke lever pivot pin on the front carb that went walkabouts. It gave me the opposite effect of no choke, hence spluttery starting with only the rear carb getting a bit of choke.

Steve


Steve Gyles

Well I'm back.

As I mentioned before there was arcing between the positive wire from coil to the distributor and the spark plug wire.

I replaced the spark plugs, spark plug wires. I also cut down the wires from the distributor and replaced the female bayonet connectors. That quelled the arcing

The car ran after that, but wouldn't idle well.

I adjusted the valves and the car still isn't idling well.

Before I go chasing around adjusting timing and carburetors (which were all fine before the arcing)

I am curious if it is possible or indeed likely that the arcing damaged the Pertronix electric ignition in the distributor?

Additionally perhaps damaging the coil?
Tysen McCarthy

If you had to adjust the valves much then you might have to adjust timing and mixture or at least check them.

I don't know how robust Pertronix are, coils are normally pretty robust, but rotor arms and dissy caps can play up or be of poor quality if of more modern make.

I also now wonder about doing a compression test on the engine as poor idle could be from the valves and/or head gasket.
Nigel Atkins

Maybe I'm being stubborn, but I think the arcing effected the solid state electronics in the distributor. It was after all the positive line from the electronics that was arcing.

The coil may not be the culprit but it is 10 years old and probably worth changing on general principals.

I really don't think its compression. The valves weren't off very much at all. The head gasket and all involved only have 10,000 miles on them.

I think I'm just going to replace the pertronix stem to stern.
Tysen McCarthy

A burned HT wire can cause all of those problems. If a carbon core wire is not properly terminated, it can result in a bad connection and a spark inside the wire end where you do not see it. The longer it runs the farther it burns the carbon core back up inside the wire, and the longer the gap gets, the higher the resistance.

At some point you may begin losing spark at the plug with intermittent misfire that gets worse with time. As the air gap in the wire gets bigger it takes move coil voltage to drive the spark through it. Higher HT voltage at the coil can eventually lead to spark arcing across outside of the coil tower (and you still may be misfiring on only one cylinder).

Check resistance of all of your HT wires, from end terminal to end terminal. Solid core wires should be close to zero ohms. Resistor wires should be about 5000 ohms per foot of length. 50-megaohms or open circuit usually means a burn out at one end of the wire. That may be fixed by cutting back the burned end and reconnecting the terminal.
Barney Gaylord

Coils normally last decades but they're not expensive to buy if you've have any uncertainty about it.

Believe me mileage and head gasket failure don't always correspond.

If you can swap the Pertronix out with anything then that might confirm your thoughts.
Nigel Atkins

I've ordered a replacement pertronix ignition module.

https://mossmotors.com/mga/electrical-ignition/ignition/pertronix-flame-thrower-replacement-module

It was the positive wire from module that was arcing. I think its fried.

I also ordered a new coil, just because, and its an relatively inexpensive item.

So by next I will have replaced

plugs
ignition wires
cap
rotor
module
coil

I'll report back.
Tysen McCarthy

Different matter now you've put it was a wire to the Pertronix! :)

In a way it's good news as the replacement should sorts things and get you back to where you were. Of course you need to find out why this happened.

Take care on installing the new igniter head, those wires tend to be delicate, and allow enough slack so they don't fray inside dissy cap with baseplate movement.

Pity you didn't see Mike's thread, you could have dumped the whole dissy and gone fully electronic with a CSI or 123 fully electronic dissy (some will be getting the vapours at the thought). :)

Nigel Atkins

As to why it happened I think it was caused by two things

1) the wires from the module have crimp on female bayonet links without heat shrinking. I think the wire worked open where the "collar" of the crimp on fitting opened. (I'll use heat shrink)

2) an ignition wire was run too close to the above and they started arcing. I ran that closer to the other wires.

Regarding fully electric. $459 is a little too dear right now.


Tysen McCarthy

It doesn't matter if you've got it fully sorted but I must admit to being a bit lost (though that's not difficult or rare), bayonet links(?) and close wires arcing(?).

I'm all for everything fully insulated, I don't like the fusebox connections and battery post clamps being live and bare (but not that bothered to do anything about it).

Wires can surely only arc where they're not insulated, unless one gets the other so hot it melts the insulation.

I know HT leads can crosstalk which is why I like to keep them separated and well routed with combs but insulated low tension wires should be able to be bundled together and are in the loom and sub-looms.

I hope the new bits get this sorted for you, some are service items so may give small improvements anyway, costs do seem start running up unexpectedly on our classics so I well know, many times, what you mean about controlling expenditures at any given time. Good luck.
Nigel Atkins

The final conclusion:

The solid state sensor was fried and the ignition coil was aging or damaged by the arcing.

I replaced the sensor and it got back to about 90% and replacing the coil got be back to 100%.

Proving yet again that 90% of what appear to be fuel problems are actually electrical problems.

I'm going to check the timing and fiddle with the fuel mixture just for good measure.

Thanks to all!
Tysen McCarthy

Well done.

Don't fiddle the carbs adjust them after checking the timings and once you have them set right leave them alone.
Nigel Atkins

This thread was discussed between 03/06/2020 and 11/08/2020

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