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MG TD TF 1500 - Fuel Problems ???
|Recently had a breakdown, after a short period of no power. The fuel pump was clicking a mile a minute, found feed side of pump loose ? sucking air. Tightened pump back to normal a few clicks then only occasiional, but hard to start and would not idle and in fact would stall out and wouldn't accelerate. Lifted pot lids as once before floats had become hung up when dry. Just opened both pots and engine turned over as easy as ever, accelerated well drove off for a trial run post a few minutes while going uphill again stalled out and wouldn't acclerate/take fuel. Looking for some advice where to start looking maybe a stepwise checkout. Again at this time fuel pump seems 'normal" will start but will not idle or accelerate, all started with loose fuel tank side of pump
|Jon - Disconnect the line from the pump to the rear carburetor at the carburetor, direct the line into a quart jar that is marked at the 1 pint level, turn the ignition on and see how long it takes to pump 1 pint. It should be about 50 seconds. Anything longer than that would indicate a possible clog on the inlet side of the pump or a pump in need of rebuilding.
Regarding the floats hanging up when the float bowl is dry, you have a float lever that is dropping too far and jamming against the needle. See the article, Float Lever Drop Adjustment in the the Other Tech Articles section of my web site at: http://homepages.donobi.net/sufuelpumps/ for instructions on how to make the adjustment. Cheers - Dave
| When it fails to start or stalls, the pump is not clicking like mad, just content to click once in a while? If you push the tickler down, does the pump speed up and squirt gas out the top? Yes? No? If the pump is up to pressure but carbs starved, it sounds like the strainer in the carb banjo fitting is plugged.
It is possible crap has choked off supply in the tank fitting strainer, fuel pump strainer, float bowl strainer, and I've even found rust accumulated in the elbow under the tank choking off flow.
A large accumulation of rust in the bowl would cause it to run lean through the whole range all the time, but it sure doesn't hurt to scrape it out once in a while. I broke down and coated a few tanks but still find traces of rust (maybe residual from the line & fittings).
|Or a wasp Jim.
|Could be ethanol gunk sticking everything. Remove the floats and make sure there isn't gummy sticky stuff on them, and the walls/bottom of the float chamber. George
|Jon, Just my 2 cents, recently had the same problem. Found it was missing one of the two fiber washers on the inlet side of the pump and I believe it was sucking air into inlet, not leaking. Lucky find, works great now. Bob
|R.AF. Robert Finucane
|Took Dave D's advice pumped ~3 onces in 50 secs, nice slow ticking (seemed apprpriate rate) would it be appropriate to back blow the inlet side with pressurrized air and would the most likley place for a clog be the in tank filter mesh. A ne wone was placed with a new fuel line a few years back, the tank rinsed but not lined.Would it be worthwhile or productive to hang a magnet inside the gas tank to attrcat and accumulate any rust.
I have had a similar problem. Replaced the pump as mine was very tatty and not original.Still would not run properly, ticked over Ok but wouldn't accelerate. Had one or two small leaks so bit the bullet and removed the tank, although the tank had been relined by PO there was still traces of rust in the tank. Blew the line back from the pump and removed small amount of debris (no wasps). The tank had been repaired in numerous places and when I washed it out with the pressure washer lots more holes appeared. Brought a new tank lined it with POR 15 and have had it respayed, hoping to fit it next week. Updates to follow.
Mick 52 TD
|Jon - Rerun the test, this time with a line from the inlet side of the tank into a can of fuel or mineral spirits and see what the time required to pump a pint is. This will tell you if the problem is in the tank to pump line or if the pump is in need of help. As for a magnet inside the tank - my feeling is that it would be of minimal help. if there is rust in the tank, the only sure way to cure it is to have the tank dipped in a caustic bath to remove all traces of rust and then either sealed or have it treated with zinc phosphate. One of the problems with using any kind of a sealer is that while the sealer may work fine with today's fuel fuels, there is no guessing what may be put in the fuel of the future. I used aircraft slushing compound in the tank of our TD 30 years ago when I restored it. About 5 years ago, the compound (that had served very well for 25 years) started dissolving in today's fuels, totally gumming up the check valves in the fuel pump and the needle valves in the carburetors. I had to have the tank entirely stripped (unfortunately including the exterior paint) and this time I opted for the zinc phosphate treatment. Cheers - Dave
|Dave B, any idea of the thread and size of the inlet side of the SU pumps. I'd like to make up a line to check that side of the fuel pump as you suggested ( would be easier if I know dimensions versus taking pump off)
|John - The fitting is a 1/4 BSP compression fitting. See Fig. 11 in the chart, Fuel Line Fittings in the SU Fuel Pump Articles section of my web site at: http://homepages.donobi.net/sufuelpumps/ It might be easier to just get some flexible fuel line (probably 3/8 ID and screw it down over the male threads on the pump. If you make a nice square cut on the flexible line, you should be able to get an air tight fit by screwing the line down tight against the outlet fitting. Cheers - Dave
This thread was discussed between 15/07/2010 and 17/07/2010
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