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MG MGB Technical - Hesitancy randomly generated

I'm Back!

Sorry, still cannot sort out this problem. 71B runs fine MOST of the time, but, on occassion, begins to loose power and sputter, almost, but not quite stalling... slight backfire.

I've changed distributor cap, rotor cap, electronic ignition, grounding wire and plate within the distributor cap, spark plugs, wires, and fuel line filter. I've checked the fuel pump lines and electrical connections and fuses. I replaced air cleaner and topped off the oil. Engine is imaculate and I see and smell no leaks. Engine does burn some oil though, 1 quart every other fill up. Checked tranny fluid and radiator fluid and is fine. Idles at 900 rpm.

What now?

Bart
BartTS

You know, I'll bet it's that SU fuel pump again, I just hate those things. I had the same problem and I did everything you've done and more (repleaced coil), replace points (both sets) etc.. etc. Eventually I replaced the pump (2nd hand '83 Subaru, cause I had one spare)
Try unhooking the the fuel line and running some petrol into a container for a while (or back round to the fuel tank if you've a line long enough). I noticed mine sounded slightly irregular just prior to its final swan song.
It mostly did the coff splutter routine after periods of inactivity (early on the morning) but other times at random. Eventually it took to dieing out altogeather on the very top of a very large bridge we have here.
Peter

Heres another thought: Does it only do it after you pull away from a stopped condition? In which case the front brakes may be dragging due to the old front brake hoses being in a partial collapsed state, thus holding the brakes on for a bit.
Andrew Blackley

Bart
Here are a few suggestions to try and help solve the conundrum.
1) Change the coil.
2) Ensure all the connections on the low-tension side of the ignition, i.e. the smaller wires, are good.
3) Have a look at the float (s) in the carb. fuel bowl, ensure they are correct.
4) Ensure the heat shield, between the carb. and the exhaust manifold is good, with no cracks and with the asbestos attached.
5) Recheck the fuel pump when the symptoms reoccur.
If non of our suggestions work, then make a note of when the symptoms occur, like when the car is hot, if it is going round a bend, over a sleeping policeman, then post another request for help
Cecil Kimber

Have you looked under the bonnet just as it goes odd? Could it be that there is water getting onto your disi, either from the heater valve or from an aggressively weeping head gasket?

Just a though. Have a butchers if it lasts long enough.
--
Olly
Oliver Stephenson

Bart;
Also check the ground for the fuel pump if you haven't done so. It is inside the trunk, on one of the license plate bolts. Mine was loose many years ago, and would cause intermittent cutting out/stalling. It used to be a joke"No wonder your car won't start, the license plate is loose". It actually apllies to these cars!.

Pete H
Pete Haburt

I've just realised that my fuel pump has always been grounded through the fuel line. Nice.

--
Olly
Oliver Stephenson

This thread was discussed between 27/05/2002 and 30/05/2002

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