TR6 Won't start after 10-mile run

[pdplot]

Well it finally happened to me too. After a flawless 10-mile run - my first in about 3 weeks - I parked in my driveway, checked the oil and under the hood and tried to start to put back in the garage. Cranked over and over but no joy. Nothing. No spark. Points were almost closed so I adjusted to .014, replaced (almost new) condenser. Tried to test coil but Radio Shack multi-meter was apparently malfunctioning and readings were all over the lot and finally read 0L. 12V Battery in multimeter tested ok. I tried a spare coil (old) but still no luck. Fuel pump is working ok- when I squirted some starting fluid in the carbs, nothing happened. Now what? Another coil from Auto Zone? Another multimeter?Anything else I should check? I need help.

 

[Geo Hahn]

On my TRs (3 & 4) the first thing I would check is the white/black wire from the coil to the distributor. I assume the TR6 has something similar.

That wire can break internally close to the connector and look okay, but not be making contact.

 

[poolboy]

If that's OK then run a jumper wire from the white wire side of the fuse for the green wires to the + terminal of the coil and try starting the engine

 

[TexasKnucklehead]

I carry a spark plug on the end of an old wire. It's a snap to pull off the coil wire, stuff in the plug/wire, lay the plug on the valve cover, and turn it over to see spark while cranking. Then repeat with a wire coming out of the distributor (but know it will only spark as often as that cylinder fires). Too often that rotor shorts internally, and you will have no spark.

 

[pdplot]

Thanks guys. I bought a new coil at Auto Zone and a couple of small 12V batteries, one of which I put into my cheapo Radio Shack multimeter. It now works again. I tested the new coil - .03 primary and 8.50 secondary. Guess what? Same as one of the old coils, the other one was 7.19 secondary. OK. I think it's a broken wire too. I tested the red wire from the minus terminal to the distributor and it was fine. I didn't test the black wire into the plus side of the coil because I wasn't sure where the other end was. I think I know now - the fuse box? My coil /distributor wires are black in and red out. BTW, I also get no continuity readings from one end of the hi-tension coil wire to the other nor on the one spark plug wire I tested. I used a 12V power supply on my workbench. Is this normal? Too much resistance? These are the green ignition wires and have never given me grief in 20 years of ownership. Lucky for me it broke down in my driveway as I had ventured out without my cell phone. Last time I do that.

 

[TR3driver]

Anything from around 7K to maybe 12K is normal for the coil secondary. Most continuity testers will show that as an open circuit (even though obviously it's not).

+1 for testing for spark right at the top of the coil. After that, I would be checking the voltage at the coil primary terminals with the ignition on, first with points closed then with them open. With the points open, you should find full battery voltage on both terminals. With the points closed, the coil terminal connected to the points should be near ground (less than 1 volt). The other terminal should be either near battery voltage, or around 6-9 volts, depending on whether you have a ballast resistance in the harness or not (early TR6 did not, later TR6 did).

If that looks normal, my next step would be to change the condenser.

 

[glemon]

It sounds like your coil (s) is ok. They are pretty reliable. If all else fails follow the steps by step in the Lucas Fault Diagnosis manual for coil ignition. Easy to find online if you Google it. It gives a nice step by step in logical order with nice pictures to help you understand the verbal descriptions.

 

[NutmegCT]

On my TRs (3 & 4) the first thing I would check is the white/black wire from the coil to the distributor. I assume the TR6 has something similar.

That wire can break internally close to the connector and look okay, but not be making contact.

Same thing happened to me on my TR3. Exactly. Took forever to realize that wire was broken inside. Wow - talk about frustrating ...

Tom M.

 

[Mickey Richaud]

Same thing happened to me on my TR3. Exactly. Took forever to realize that wire was broken inside. Wow - talk about frustrating ...

Tom M.

Either that, or it may be shorted to the points' mounting plate. Be sure the insulator is centered on the post!

 

[pdplot]

I was wrong about the plus side coil wire. It's white, covered with black rubber. The green wires go into the alternator. I set up a test light between the fusebox terminal for the green wires and the white wire into the coil and there is continuity with ignition on. Light lit when I touched it to the engine block. The new coil I bought got hot when I was fooling with the wires. Is this normal? Still no spark from the hi-tension cable to ground when I open the points with ignition on with any of the 3 coils I now have. If no spark going into points then shorted plastic spacer wouldn't matter - correct? There has to be a hot spark from coil tower cable to ground with ignition on and points opened with a screwdriver. I believe the spacer is fine. This is baffling. What else could it be?

 

[sp53]

I am not a tr6 guy, but if the timing chain was broken and the rotor did not spin would that cause those systems? So does the rotor move when you crank the motor?

 

[TR3driver]

I don't see anything that would identify either a shorted insulator or a broken wire (at any of several points), or a shorted condenser. The tests I gave before will.

Opening the points by hand doesn't always work either. It's better to crank the engine.

 

[pdplot]

Mystery solved. On a hunch, I replaced the points with an old set I kept "just in case". It has a plastic post not metal. You guessed it - the old points somehow shorted out. After adjusting the gap to .013 it kicked over and started. I advanced the idle speed to charge the battery back up and its racing away at 2200 rpm. Thanks to all. It's been a while since I had to do any diagnostic work but at least I know what it wasn't and I now have 3 working coils. Now if only someone could tell me why my desktop has suddenly gotten dog slow on the Internet...

 

[pdplot]

Listen to this. I went out to start the car and move it into the garage - but - it would not start-again. Huh? I took a good look at the coil and noticed that the minus terminal was very close to the metal fuel line - maybe less than 1/4 inch but not touching. On a hunch, I loosened the terminal nut and rotated the 3-prong terminal away from the line. Sure enough, the car started right up. I attached a jumper wire from the terminal and touched it to the fuel line. Sure enough, the engine stumbled, and when I clamped it onto the fuel line, the engine quit. Did anyone ever hear of that? Also my temp gauge and fuel gauge were not working. My first guess was a blown fuse and I was right. A replacement was found and another problem solved. These cars will keep you on your toes.

 

[poolboy]

Yeah, but is your computer up to speed now ?

 

[pdplot]

My computer is a bit faster but still quirky.
I'm curious. Somebody else try to attach a jumper to the minus post of the coil and touch it to the fuel line to see if the engine quits running. Post your result here. Thanks.

 

[poolboy]

No, but it makes sense that it would, though. If you ground the coil at it's negative terminal, it would negate the effect of the breaker points.

 

[Geo Hahn]

No, but it makes sense that it would, though. If you ground the coil at it's negative terminal, it would negate the effect of the breaker points.

In fact - that is what my anti-theft device is. A simple toggle switch that grounds that side of the coil. If flipped while the engine is running it may cause a stumble or kill the engine. If flipped before cranking the engine will not start.

 

[pdplot]

You mean I re-invented the typewriter?
I hope it starts tomorrow morning. You never know.

 

[NutmegCT]

So - did it start this morning?