Electrical fault trace sequence.

[John Morralee]

I was 5 blocks from the 2009 Healey Conlave in Kingston when the engine of my '63 BJ7 quit!! My diagnosis was correct no spark. After so many continuity checks I was dizzy by the time the fault was found to be the distrib.rotor ;possibly an intermittent breakdown of the rotor. We succeeded after being reduced to replacing parts utill the problem was solved.What would have been a fault/check sequence? We did so many different ones in trying to trace the fault I wonder if/how we missed the identifing one. A fuel supply loss for example would be : check at the carbs,check the pump,check the fuel lines etc.etc.

 

[GregW]

I guess that would depend on the symptoms. I'd probably start with checking if there was spark at the plug, if not move to the dizzy cap. Then check rotor and points if installed, verify 12 volts there. Move to coil.

 

[andybj8]

John

It might be worth checking the battery switch as many people have had problem with this. There is a small black and white wire on it which grounds the coil / dizzy when the switch is turned to off (so making the car anti theft).

You can disconnect this and see if yo have any more problems, if so replace or rebuild the switch.

cheers Andy

 

[tahoe healey]

Check the wires, inside the dizzy, to the points. They can get worn and ground out.

 

[Andy65]

If it stops suddenly like someone pulled the plug, I pull the distributor cap and and look and pull the rotor. They fail. Some are junk. Then I put a light continuity tester across the points. Looks like a screwdriver with a light in the handle and an alligator clip. See if there is voltage at the points. Just pry them open and closed. If the light doesn't go nicely, then sand paper/file the points. You can push down on the fan belt and rotate the engine with the fan to get it to the right position. I've seen grease foul out the points. Next is distributor cap. Look inside and see if any of the contacts are bent or loose. If wet weather, a near invisible crack can short it out. But sometimes you can see the spark in the dark. These are quick checks before removing a plug. Check the ignition wire from the coil to the cap. Some have a washer inside that comes loose. If the ignition light lights up when you turn the key, the points have voltage, the cap and rotor look good, then look for spark at the plug i.e. bad coil. The only other thing is the condenser which you can replace if no spark. Other tips are good, especially the one from the battery switch is good to remember.

 

[why]

If your plug wire has a rubber boot on the plug end that can pulled back onto wire that exposes the metal connector, situate the plug wire so exposed metal connector is a mm or so from metal of head/block (or some other such metal known FOR SURE to be grounded) and crank engine with starter or put in 3/4th gear and rotate front tire so you can look for spark tween connector and ground.
Jay Glass
'65 3000

 

[bob hughes]

Guys

The manual has a logical fault check sequence for electrics and non starting, followed it through myself on several occassions for different faults - it did get me there. My problems were a faulty connection between coil and Dizzy - the wire inside the protecting sheath had broken just behind the spade/ fork connection and was in intermittent contact. And the other was the centre plunger point in the dizzy was jambing and not in contact with the rotor arm and that was my fault for playing with it earlier.

Bob

 

[Johnny]

I was 5 blocks from the 2009 Healey Conlave in Kingston when the engine of my '63 BJ7 quit!! My diagnosis was correct no spark. After so many continuity checks I was dizzy by the time the fault was found to be the distrib.rotor ;possibly an intermittent breakdown of the rotor. We succeeded after being reduced to replacing parts utill the problem was solved.What would have been a fault/check sequence? We did so many different ones in trying to trace the fault I wonder if/how we missed the identifing one. A fuel supply loss for example would be : check at the carbs,check the pump,check the fuel lines etc.etc.

I agree with all of the others. I would add though, in general if the car acts up sporadically (cuts out, sputters) it's usually a gas shortage problem. Generally you can tell by lifting the hood and "sniffing" for gas, or lack of.

If the car sputters then dies and won't start it's generally electrical as was mentioned earlier.

Try not to get too excited/anxious it happens to all of us. Healey's are great cars that are not too difficult to fix on the side of the road. If at all possible always pull off the interstate or busy highways.