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 MGA - Coil - no high tension spark

Trying to get my old girl started for the first time in 15 years. I have never actually heard an MGA run before. Needless to say...I'm getting pretty excited.

I'm getting a spark off the block from the low tension wire but nothing off the high tension wire.

Should I just buy a new coil or is there something else I should be looking at?

I was planning on buying all new ignition parts anyway but did not want to introduce too many variables before the first start.

Thanks


Jeff Bennett

When you say no high tension spark I assume that is directly from the coil center, not from a distributor output lead?
Do you have a Multimeter?
If so, remove the low tension lead from the Distributor an insert the meter to read current. Turn the engine over. Does thev current start and stop?
If not, check that the points are opening and closing fully. Then disconnect the capacitor. Check for an alternating zero and infinite resitance across the point as they open and close. Check the resistance of the capacitor, if zero it is shorted.
Check the coil resistance.

Mick
Mick Anderson

Mick,

Correct - directly from the coil.

I have a meter but need to learn how to use it. Too many darn settings.
Jeff Bennett

Jeff. There is an article on ignition system trouble shooting on my website, www.custompistols.com/ on the MG section.

The coil is a transformer which works by charging the primary windings while the points are closed and inducing a higher voltage current out of the secondary wirings. As the points open and the magnetic field collapses, the high voltage current is directed to the coil lead, also called a king lead, thence to ground. If you have no spark at the coil lead, the problem can be either the low tension circuit not charging the primary wiring or the coil itself. Instructions on how to test this is in the tech article.

Les
Les Bengtson

Jeff,
When in trouble try the guru!
http://mgaguru.com/mgtech/care/cf120.htm
This gives you a step by step guide.
Mike
Mike Ellsmore

When you understand how it works it is easy to diagnose any spark problem. Read and learn here: http://mgaguru.com/mgtech/ignition/ig108.htm
Barney Gaylord

Someone needs to write an article on how to use a test meter.

I WILL learn how the ignition system works and how to maintain it but at the moment it looks like the equivalent of Chinese arithmetic.

I need someone to spend an hour with me in my garage.
Jeff Bennett

I would be happy to spend an hour in your garage, except it's a wee bit far to drive from Illinois to New York for a lunch run. Meanwhile try reading my Ignition Troubleshooting article here:
http://mgaguru.com/mgtech/care/cf106.htm
This has some information on using the test meter for these specific issues. I have "Use of Test Meter" article on my to-do list, but it may be spring before I get around to it, as I am somewhat busy with body sill replacement at the moment.
Barney Gaylord

Jeff,
Where in New York are you? The president of the Eastern NY MGA Club is Jon Rubel, he lives in Brooklyn. I most likely can get you a phone number of someone closer to you if you contact me off the BBS.
David Werblow

This thread was discussed between 12/01/2008 and 14/01/2008

MG MGA index

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