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MG MGB Technical - Fuel Pump - Power Issue?

All,
My 72 mgb roadster seems a sluggish when I mash on the gas. I've put new coil, plug wires, plugs, filed points and set to .025".
I still need to install new capacitor in distributor.
The thing seems to start with some difficulty, but then idles pretty good.

I was told the fule pump would help. They said even if you pressure check flow, diapham gets stiff and doesn't respond as it should. So, checking pressure will not always tell the whole story.

I also need to check timing, sounds like a little advancement may be helpful too reading the threads.

Thought's on need to invest in fuel pump?
Capacitor expected to make much difference?

Best regards,
Doug
DT Toms

Before spending money on fuel pump etc. I would check the timing, if it is off it will rob power.
Lewis

Doug - The fuel pump normally doesn't cause sluggish performance. If it is weak or going bad, it is more apt to cause fuel starvation and sputtering than just low performance. I agree with Lewis, check timing first and then valve adjustment. If your ignition is the old points style, check the gap of the points or check dwell angle (just an electrical means of checking the gap). A decreased gap will cause sluggish performance.

I don't know who told you that the pressure and flow rate of the fuel pump, if they measure good, is meaningless. those are the two main checks to make, with the flow rate being the most important. The diaphragm has to be in relly bad shape befor it will cause a problem and then it is more apt to cause the pump to not run at all. The flow rate for the pump in your car (assuming it is a SU fuel pump) should be somewhere in the order of 1.5 to 2 pints per minute. Just disconnect the fuel line from the carburetors and direct it into a container with a mark at the 1 pint level, turn on the ignition and time how long it takes for the level to reach the 1 pint mark, it should be somewhere between 30 and 40 seconds if the pump is good and in that free pumping set up, the pump should not falter at all during the time it is pumping.

I am sending you a fuel delivery troubleshooting guide for your use in diagnosing your problem, but I suspect that the problem is not with the pump. Good luck - Dave
David DuBois

Can someone explain "dwell angle". I have seen this before, and looking in the haynes manual, it just says " should be 60 degrees....."

But, what is it? How do I check it?

Ken
70 B
Ken Harris

Thanks everyone for your input.
I re-set the point gap to .025", was a little less. Also advanced the timing slightly. Seems to have eliminated the sluggish response to accelerator.

Still haven't put in new condensor yet.

I had an old timing light, but didn't have the instructions for it. I recall the old style that had a spring like extension you put between the coil wire and cap.

This light has a green, red and black connector. Not sure how to correctly connect what to where?

Anyways, seems to be running well and have good troubleshooting guide and rebuild resource.

Best regards always,
Doug
DT Toms

Dwell angle measures the angle of rotation that the points remain closed. This angle varies directly with the amount of gap between the points when they ar fully open and therefore an electronic measurement of points gap. Eithe method works to set the points correctly, with the dwell measurement being somewhat easier to make an accurate setting with. Cheers - Dave
David DuBois

to follow Dave...you need a Dwell Meter to do it that reads it off in degrees. Not terribly expensive and it is more accurate, I understand.
J.T. Bamford

This thread was discussed between 22/06/2005 and 23/06/2005

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