MG-Cars.net

Welcome to our resource for MG Car Information.

Recommendations

Parts

MG parts spares and accessories are available for MG T Series (TA, MG TB, MG TC, MG TD, MG TF), Magnette, MGA, Twin cam, MGB, MGBGT, MGC, MGC GT, MG Midget, Sprite and other MG models from British car spares company LBCarCo.

MG MGB Technical - MBG GT starter motor

I've been lucky enough to have been 'donated' an 1980 MGB GT. When I turn on the ignition I get a loud humming noise coming from under where the battery is in the back seat. Also when trying to start it all I get is a faint click coming from, presumably, the starter motor. I've had the battery checked and it's fully charged. Any ideas?

Thanks!!!
otleygas

The humming noise is the fuel pump (normal), and you should start by charging the batterybefore attempting to start the car.
Jeff Schlemmer

check the wiring connections first and recharge the battery if that doesn't work buy a new battery. The starter clicking is a classic sign of a dead or undercharged battery.
Mike MaGee

You said the battery is fully charged, so start checking the wiring. Below is what I wrote to someone else, which should help get you started. I wrote this regarding my '77B, and since I don't know the differences in my car and your GT, please make allowances:

With someone attempting to crank the car, measure the voltage on the battery terminals. If steady, measure voltage while cranking on battery cabling (not terminals). If steady on battery but not on cabling, clean terminals. If dropping to below 10 VDC on terminals, recharge and try again. If problem repeats, have a shop test the battery under load.

If battery voltage is steady, check the voltage on the brown wire input to the fuse block, while someone cranks. If voltage is present, but then drops significantly when ignition is engaged, check both ends of the heavy gauge wiring between battery and starter. Also check grounding at battery ground cable, and engine ground strap.

My first problem was the terminal connector on the battery end of the positive cable. The PO had replaced the original connector with one that was strap-bolted to the cable. It was loose, and provided adequate amperage for start only part of the time.

The second problem was on the starter, where the other end of this same cable had partial connection because of interfering insulation on other wires on the same starter terminal.

Fred Doyen

Indeed. Also, check the voltage at the starter motor - you should have 12V 'hot'.

Assuming the power reaching the starter motor is adequate (from battery and connections), that 'click' can also be due to a stuck starter solenoid.
CJ Walker

If the car has not been started in a long while, remove the plugs, squirt some light oil down the bores. Leave the plugs out and turn the engine by hand to be sure that it is not siezed. Then clean the battery cables and terminals, recharge the battery, disconect the fuel pump lead and try to turn the engine with the starter (will serve to build up oil pressure also).

If all does well, reconnect everything, install the plugs, turn on ignition, check float chambers for overflow then fire her up.

Good luck
J. A. McManus

This thread was discussed between 25/07/2005 and 27/07/2005

MG MGB Technical index

This thread is from the archive. The Live MG MGB Technical BBS is active now.