QuestionHi Howard,
When I turn the key, fuel pump doesn't ever stop the noise; but theres half a
tank of gas. Car cranks, but thats it. I put new plugs in, it ran great right
after, took it home, next day, no start. Seems to happen when its cold., now
not at all.
The choke seems to have no effect what so ever now, also. I removed the
rotor,which had some white looking stuff in it. I have ordered a new dist. cap,
rotor, points and condeser and sp wires.
I am now wondering if it is the fuel pump, becasue no gas smell or flooded
smell.
Thanks ...i am a newbie at this.
Chris
AnswerHi Chris,
All piston engines only require three things to run. Compression, fire & fuel. But there are conditions on each. Compression needs to be sufficient on each cylinder. On an MGB you should expect to see 135 PSI to 165 PSI.
Fire should be a thick blue spark and approximately at the correct time and in the correct order. Fuel must be a combustible fuel and be available to each cylinder and roughly in the correct ratio to air.
If an engine will not start, one or more of these is missing.
The statement you made about the pump continuing to make noise is a clue if it is an original SU pump because the SU pump clicks rapidly until it fills the float chambers, then it slows to either a halt or an occasional click. Any time you try to diagnose a "no start" you should not look for a cause but look for what is missing. Compression can go away but that is the least likely so look at fire and fuel first. Fire is easy to make a preliminary test by removing a spark plug and put the plug on the wire and lay it on a metal part of the engine and put your thumb over the plug hole and have someone spin the engine with the starter. Each time that piston comes up on the compression stroke it will blow your thumb off of the plug hole and make a "POP" sound. Watch the spark of the plug and you should see a thick blue spark that will make a "Click" sound each time it sparks. If the timing is close to correct it will seem as though the "POP" sound is causing the "Click" of the spark. If it is "Click" - "POP" or "POP - "Click" the timing is off and may be off enough to make an engine not start. Next is fuel. Put the plug back in and wire on and spray something like WD-40 in the intake while someone spins the engine over. If it then sputters and tries to run for a second or two, then fuel is the problem. Remove the fuel line from one of the carburetors and hold it in a can while someone turns the key on and you should see a good flow of fuel. (Keep a fire extinguisher handy when you have fuel exposed) If you hear fast clicking from the pump and no fuel then you have either a failed pump or an air leak in the pump to tank line.
Let me know what you find,
Howard
