TR2/3/3A No spark in TR3

[JAJohn]

I'm getting no spark in my TR3. I am attempting to bring the car back to life after sitting for 40 years. New wiring harness. New battery. With the ignition key on, pressing the starter button makes the engine turn over nicely, but when I spray a couple puffs of starter fluid into the carb throats there is no firing, no backfire. So I checked and confirmed all the wiring at the control box (which I did not replace), checked fuses (new). (There is juice to the system--I accidentally touched a headlight line to the frame and blew a fuse.) Then I took out the no. 1 spark plug and wire, and held it against the block, with ignition switch on, and I cranked using the button on the solenoid. No spark. It has a new condenser, so I switched back to the old one. Still no spark. I don't have the original coil; using a new Lucas one. New points. The black-fiber coated wire inside the points looked very questionable, so I cleaned and re-soldered it. Still nothing.
One note: The dashboard red light stays off when I switch on the ignition at the key, but when I'm cranking it from the push switch, the red light comes on. The ammeter does not move to show any drain on the battery, but the fuel gauge flips over to "full," even though there's no fuel in it.
Any hints? Suggestions? Thanks.

 

[Sarastro]

You might start by seeing if you have voltage at the coil. Check it at the terminal that isn't connected to the points. You should have the full 12V there when the ignition switch is on.

Is the other electrical stuff working?

 

[NutmegCT]

Just a guess - are all the coil and plug wires tightly connected, and to the correct terminals?

As your headlamp has power, sounds like it's "just" an ignition problem.

 

[Mickey Richaud]

Adding to the above: Check to be SURE the points' mounting on the post is properly insulated. Should be a couple of nylon spacers top and bottom that keep those "protons" and "electrons" in their places.

 

[Sarastro]

Are you sure you have the points connected right? This is a common error. You have to make the connections so they contact the spring, not the nut that holds it all together.

 

[DavidApp]

If you have the points set that the plastic cam can be removed make sure the fiber washer is under the cam.

You can run a wire from the battery positive (live) side to the coil then try to start it. That will eliminate all the wiring.

Plug wires in the correct order? 1, 3, 4, 2.

David

 

[poolboy]

Here's another view of the proper points installation..Notice the position of the insulators.

 

[JAJohn]

Thanks for all the comments. I attacked it today: Referring to the diagram, it was missing fiber washer no. 6; I had added a tiny metal washer between nut no. 1 and insulating sleeve no. 2.
But still no spark. I rotated the cam to close the points, then opened them with the ignition on. No spark at the points. With a tester, I checked connections and the spring contact no. 5 does not have any juice. Connecting the contacts on the side of the distributor with the coil shows just under 12 volts on the tester.
The engine turns over with vigor. The plug wires are new, and in correct 1,3,4,2 order. Anyone have further suggestions?

 

[Sarastro]

When you check the voltage at the spring (5) the points have to be open. If you have the ignition switch on, everything is hooked up, the points are open and you still have no voltage at that point, the spring is either shorted to ground or you have the connecting wires 3 and 4 hooked up wrong.

That fiber washer is essential. Without it, the points short to ground. The whole idea is that the points interrupt a connection to ground. If they are connected continually to ground, nothing will work.

 

[JAJohn]

Sarastro, thanks for the tips. How can the connecting wires 3 and 4 be hooked up wrong? Does it matter which one is on top?

 

[poolboy]

No, but is #2 situated properly ?

 

[Graham H]

You could have an earthing problem at the instrument panel, the fuel gauge will go straight to full if it has no earth and that could be why the ignition light is not coming on with the key.

Graham

 

[Sarastro]

3 and 4 must be between the spring 5 and UNDER the top hat 3. Electrically it doesn't matter which is on top, but they whole thing will fit together better if assembled as shown in the figure.

The idea is that the connection must be made to the spring and insulated from ground. The top-hat thingy insures that.

I'm more worried about the missing fiber insulating washer, though. If it's missing, nothing will work.

 

[poolboy]

Yeah, #'s 2, 6 and 7 have to be where they belong.

 

[sp53]

I put some new points in my tr3 the other day and they were made different. The insulating stuff was switch around. I will try and get a pic today. I remember at the time I thought wow this could cause problems. Anyway try putting your old points back in and see if you get spark.

steve

 

[JAJohn]

A “no-spark” update: Success! Good spark now. To get there, first I visited the British Transportation Museum in Dayton and saw that the white and black lines to the coil were reversed on a TR3 there, so I switched the white line to the left connector on my coil and the black line to the right side. Then I checked the spark plug wires for a good tight fits at the cap (whoever invented those screw-in nail-type connections should be ashamed) and replaced the coil-to-center post line. Lastly, and perhaps most important, I re-fitted the points and discovered the little “top-hat” insulator (no. 2 in the diagram) was cracked, such that the “brim” was separating from the body of the insulator. Meanwhile, I charged the battery. When I turned on the ignition and pressed the solenoid button, the engine turned over and got a good spark at plug No. 1 held against the block.

Thanks to all who provided advice. Any one of those fixes, or all of ‘em, could have been the issue. Now to hook up gas lines and get gasoline in it, the next step that may get me back online. Thanks again.

 

[NutmegCT]

John - congrats on the victory. Who'd have thought to visit a transport museum to find an answer! Sharp eyes indeed.
Tom M.

 

[Graham H]

Is your car positive or negative earth because that is what determines which wire goes where on the coil, the coil connections should be marked so you know which is which. It won't make any difference whether you have spark or not

Graham

 

[poolboy]

Right..there will be spark even if the wires on the coil are reversed...It must have been one of those other things.
Anyway ..congratulations on that.

 

[JAJohn]

So...my car is positive ground. Does the white wire go to the driver's side or the fan side of the coil? It's on the fan side now.--jj