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MG MGA - No Spark No Start

Can you guys help me figure out what to do next? I have 12v going to the coil but nothing coming out on a NEW Lucas Sports Coil when ignition is on. When tested with an OHM meter I show 4.5 Ohms between the two terminals of the coil. I have no spark from the coil through the lead wire to the distributor cap. The lead wire tests good. The coil is warm to the touch after just a few minutes. These are the same symtoms that lead me to toss the original coil and buy the sports coil. I must be missing something simple.
David Holmes

If the points are closed then the negative side of the coil will be at earth potential and thus if you were to measure between that point and earth you should see nothing. If the points were open you would see 12 volts.
It muight be easier if you were to describe what the fault with you car was?
Bob (robert) I am turning? yes I once owned an MGWasp!!

By the way have you put a new set of points in which has caused this problem, I am wondering if you have shorted the dissy wire to earth on the points pivot post?
Bob (robert) I am turning? yes I once owned an MGWasp!!

David. Was the engine ever running with the current points? Bob has a good point, as what you describe is exactly what would happen if a new set of points were installed incorrectly. The plastic washer goes through the wire from the coil and the wire coming from the condensor, then, is attached to the hole in the arm of the points set. Thus, it makes contact with the spring arm which is insulated from the standing stud by a plastic washer at the top and bottom of the spring. If the wires are attached to the post without both of the insulators being in place, there is a short to ground, the coil overheats and the points and wiring can burn up if left on for too long.

Les
Les Bengtson

I am trying to start the car for the first time. Everything is new. I am not getting spark from the coil to the distributer. I removed the lead on the distributor side and held it to the block to check for spark (yes, with insulated pliers)and there was none. I have 12 v to the coil. The coil is new. I will check to see that the points are open. What is preventing me from getting spark?
David Holmes

Les, Thanks, I will check the assembly of the points and make sure they are as you say.
David Holmes

Thanks Les, One problem solved. I have 12v at the coil and coming out of the coil. I have 12v at the end of the wire going to the the distributer and to the points. I have 12v on one side of the points 0 on the other side with the points open and 0v when the points close. Does that mean that the points are bad? possible coroded? They've been sitting there for over a year.
David Holmes

David. I cannot check it right now because it is, quite literally, hotter than hell out. Perhaps this evening, but the tempertures are still in the high 90's at 10 pm. Thus time in the garage is limited.

Might I simply suggest that you hook up the coil lead to the coil, hold the end near the engine block and turn over the engine? If you are getting a spark, you know your points are working to some extent. If you get a good, hot spark, you know they are working well.

Les
Les Bengtson

Les, I cleaned the points. Yes they were corroded and now I have spark all the way to the plugs. On turning the engine over it did not fire up. It did backfire twice. I will check the timing next. (I set the timing when I put the dist. on and static timed it way back then.) I'll keep on. Thanks again. Next time I am on I hope it is to say hooray!.
David Holmes

David. Might I suggest to you my website at www.custompistols.com/ for some ignition related tech articles. It includes on on trouble shooting the ignition system and one on timing the engine. The latter starts with removing the valve cover and making sure you actually are on the compression stroke of the number one cylinder when doing the timing.

Your symptom might indicate that you have the distributor 180 out. Hence, starting from the beginning and verfying everything, as you did with the distributor system, might allow you to get your engine started. Always a happy thing when that happens.

Les
Les Bengtson

I thought I was being so careful on the initial set up but maybe it is 180 out. Valves are set, spark is strong to the plugs, fuel is being delivered (carbs were rebuilt by a pro and set up to run) Lots of cranking and a few coughs of white smoke from the carbs and a couple of pops but no go. Ill check to be sure I am not 180 out tomorrow... I'm done today and finishing a beer. If I am not 180 out then what?
Thanks for the link Les. Very helpful.
David Holmes

I won't mention what idoit did this, do you have your wires on correctly. When putting them on the dist. cap, this stupid person wired it 1-3-4-2.....from looking at it from the inside instead of looking down at the top of the cap. I ,I mean this stupid person was able to finally get it to start but had to hold 3000 rpm to keep it running. Itis amazing when you wire it up right and it purrs like a kitten
JEFF BECKER

This thread was discussed between 11/07/2006 and 12/07/2006

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