TR4/4A no spark in start position

[nbailey]

I have a 67 4A. Pertronix distributor, flamethrower coil, cobalt plug wires, champion plugs (.025), and healthy battery. I can only get the engine to fire as the key is released from the start position. On a cold start I have to use many short cranks to get a start. Any extended cranking results in a flooded engine. With a warm engine I get immediate starts with just a blip of the key. Once started the car runs great. Has anyone else had this problem? Thanks in advance.

 

[TR3driver]

A couple of tests to try:
1) Temporarily connect a jumper from the distributor side of the coil to ground. Turn the key on and check how much voltage is actually making it to the hot side of the coil.
2) Check the battery voltage while cranking.

I had exactly the same symptom, caused by not enough voltage getting to the Pertronix during cranking. In my case, it was a faulty battery (which failed entirely a few months later), but you could have a bad connection somewhere that is also causing low voltage. The Pertronix is rated for a minimum of 8 volts, while points will continue to work (to some extent) down below 6 volts.

Could also be a problem with the Pertronix requiring more voltage than usual, possibly from previous overheating or just defective.

 

[nbailey]

A couple of tests to try:
1) Temporarily connect a jumper from the distributor side of the coil to ground. Turn the key on and check how much voltage is actually making it to the hot side of the coil.
2) Check the battery voltage while cranking.

I had exactly the same symptom, caused by not enough voltage getting to the Pertronix during cranking. In my case, it was a faulty battery (which failed entirely a few months later), but you could have a bad connection somewhere that is also causing low voltage. The Pertronix is rated for a minimum of 8 volts, while points will continue to work (to some extent) down below 6 volts.

Could also be a problem with the Pertronix requiring more voltage than usual, possibly from previous overheating or just defective.

update: I did the checks, 11.5 volts with jumper, battery 12.8 going to 11.5 under starter load. I changed out plugs to some Bosch 4032s I had, and seemed to get better starts, although only again as I released the key. I decided to do a compression check and got 150,159,150,149. Following the compression gauge instructions , I grounded the coil . Now I appear to have no spark at all. Did I kill the coil? Thanks

 

[Geo Hahn]

What you describe would not kill the coil. Indeed, the coil is grounded many times per second as the engine runs.

I cannot, however, say what your set-up would do to the Pertronix unit. Those (as I understand it) are more vulnerable than a coil.

You might double check all your connections since you messed with at least one.

 

[nbailey]

What you describe would not kill the coil. Indeed, the coil is grounded many times per second as the engine runs.

I cannot, however, say what your set-up would do to the Pertronix unit. Those (as I understand it) are more vulnerable than a coil.

You might double check all your connections since you messed with at least one.

Well the continuing saga- after playing with this all day, I finally got it started - don't know what changed. I had checked connections, etc. Car ran good after start. I am considering calling Advanced and going back to stock distributor and points.

 

[NutmegCT]

Well the continuing saga- after playing with this all day, I finally got it started - don't know what changed. I had checked connections, etc. Car ran good after start. I am considering calling Advanced and going back to stock distributor and points.

Stock = good idea.

Congrats on getting it running again!
Tom M.

 

[Vila]

I have heard of similar issues with the Pertronix setup before, one minute it is working and the next it is dead. Never heard of one returning from the dead before, but who knows.

When I bought my 62 TR4 to previous owner added the Petronix system. I bought the car specifically to do a restoration and only drove it 50 feet before starting the restoration. From the seller parking spot to a trailer and then the trailer to my garage. When I restored the car I returned it to all original condition, including the distributor.

Points wear out and need replaced, but you can generally tell the performance begins to fade and then you know it is time to change the points. The Petronix system works great and continues to work great then the next thing you know it is dead.

 

[TR3driver]

If it happens again, try to check voltage at the coil while someone holds the key to turn the starter. It's not a common problem, but I have heard of faulty ignition switches that sometimes open up power to the ignition when in the 'start' position.

 

[nbailey]

,. le

If it happens again, try to check voltage at the coil while someone holds the key to turn the starter. It's not a common problem, but I have heard of faulty ignition switches that sometimes open up power to the ignition when in the 'start' position.

Update: Last sunday took a drive, as it was a nice sunny day here in the northwest. Car started easily (lightbulb is brightest before it burns out ? ) I got 10 miles , got a couple of misfires and engine quit. I
got it started again, got 5 miles from home and it died completely. After a $162 tow, car was safely home.
With the help of Blane Graham at Moss, was able to determine that the Pertronix was working. Taking Randall's and Blane's advice, we determined the coil was bad. I just installed the replacement Flamethrower coil, and the cold start was instantaneous without releasing the key. I've probably had hard starts for 18 months. If anyone suspects a Pertronix is bad, Blane had me just connect a test light between
+/- at the coil and crank the engine. If light blinks, unit is working.
Thanks to all for your suggestions.