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MG MGB Technical - Fuel starvation/tank?

1963 MGB, original fuel tank (I think..) Coming home from work a few weeks ago, car starts running extremely rough, like fuel starvation. Car stalls, pump is ticking like mad, coast off exit, into awaiting gas station (Lucky!) I put in 3 or 4 gallons, car fires right up, jump back on highway, get 2 or 3 miles, car dies again, pump still ticking like crazy. Call AAA, get towed home. Diagnose problem as clogged in-line fuel filter between tank and pump. Hey, it's been a couple of years since I've changed it, probably due anyway. Change filter, run car in driveway for 1/2 hr or so, all seems well, head off for a weeks vacation (without MG.)
Fast Forward 2 weeks. Home from vacation, temps in mid 90s and very humid, not MG weather for me at all. Weather finally breaks, jump into the car after dinner for a nice leisurely ride, get 3 miles from home, car dies again, pump again ticking like crazy. I limp home, about an hour to go 3 miles. Siphon as much gas from tank as I can, replace all rubber lines, new fuel filter between tank & pump, and another under the hood just before the carbs. Using compressed air I blew out the line going into the tank itself. Put in 2 gal of fresh fuel, run car, check for leaks, off to gas station. Put in another 2.5 gal, just in case I have to siphon it out again, so now I have approx. 1/2 tank of gas. I go for a ride, and notice that on left hand turns I get a sputter as I make the turn. The fuel pump is ticking as normal, not constant as when the problem first started. Right hand turns, everything is OK. I figure that this is due to fuel sloshing around the tank. I am seriously considering replacing the tank, as I figure it to be almost 40 years old. I am just wondering if there is something else that I may be overlooking? I don't want to get stranded again.
Thanks,
Steve
Stephen P Bartley

I had a similar problem w/ my '80 B. After trying most of the solutions you attempted plus a couple more,
I discoved that insects (mud daubers) had clogged the fuel line running underneath the car between the tank and fuel filter. Very little gas could make its way to the engine and a vaccum was being created in the tank.
The way I remedied the problem was by cutting out the section that was clogged and reconnecting w/ rubber fuel line and worm clamps.
I hope this helps.
Jack Landis

Before doling out cash to buy a new tank, I'd first take the fuel pump apart and give it an inspection.

Any tiny bit of debris (rust from the tank?) caught in the vicinity of the intake or outlet valve could cause either or both of them to stick open and would cause the pump to tick away without letup.
Daniel Wong

When the car fails, take off the gas tank cap - is there a hiss of inrushing air? The tank vent is in the cap. If this tiny hole is blocked the car will suffer fuel starvation just like you describe.
Mike Howlett

It could also be debris in the tank sloshing around until it comes up against the fuel pickup tube. Some MGs came with an in-tank filter on the end of this pickup and others (and especially replacement tanks) did not. I have had this happen on a couple of vehicles and what it took to resolve the problem was to empty the tank, take it off, and take it to a radiator shop to have it boiled out. You can then decide to either have the tank lined with one of the tank liner compounds or to simply paint it inside with Rustoleum DampProof red primer. If you choose to do either of these, and your tank has a screen filter on the end of the pickup tube, blow some compressed air thru the fuel pickup line to blow the still wet paint out of the screen or you will really have a blockage! DO THIS BLOW OUT WHILE THE PAINT/LINER IS STILL WET!! Then, set the tank out in the sun for a couple of days at least to bake the solvents out of the coating and to get it to set up hard before introducing fuel. Today's fuels will attack a large number of things, especially if they are uncured.

The best preventative in the future is to add a fuel filter between the tank and pump inlet and also, perhaps, one after the pump but just before the fuel pressure regulator (if you use one) or the carbs. The second may sound a bit extreme, but given the age of your car, you could well have an accumulation of crud and grunge in the fuel line all the way to the carb, and modern fuels can eat that crap loose too and it ends up clogging regulators and carbs. FWIW, and good luck!
Bob Muenchausen

This thread was discussed between 25/08/2002 and 26/08/2002

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