View Full Version : TR6 TR6 won't start when hot?

03-19-2006, 09:18 AM
I have just had my TR6 out today - the first time this year with the roof down and I just stopped at a shop and when I get back into it - it won't start.
This is a long time problem with this car but I don't know what's causing it?
It starts fine when cold and as long as you don't drive it too far (hence does not get too hot) it will perform great. However if you stop it at all when hot you can forget about starting it again until its cold?
Can some one give me some ideas as to what to do - I am at my wits end over this and my precious TR6 is now as we speak still stranded outside this shop. (I should have left it in the garage of course - it being a national holiday weekend here over flippin St Patrick. /ubbthreads/images/graemlins/hammer.gif

03-19-2006, 12:23 PM
Assuming the batt spins the motor at a normal rate and you don't have gasoline running out of the carb's, you have either a fuel problem (lack of fuel at the cylinders) or an ignition problem but likely will not be both.

Further assuming that you do not have PI (if you do have petrol injection stop reading this because I have no clue about that type of system); my first thought is a vapor lock in the fuel line. I find a spray can of starter fluid will resolve the question about no fuel at the cylinders. Just a little spray at the intake orifice will make the engine fire if the ignition is working. If a little spray does not make the engine fire, you have ignition problems, mainly no spark at the plugs. If there is an ignition problem, I suspect the primary supply for the ignition coil in the start mode is some how sensitive to heat and will not conduct there by not allowing any power to the coil. If it is just in the start mode you should be able to restart the car with a push and trouble shoot the specific problem in the primary feed to the coil.

03-19-2006, 03:25 PM
Thanks for that - I should have said I think it is an ignition related problem as there is no spark to the plugs at all when it is hot. I have switched coil's a few times with no improvement.
I don't understand what you mean exactly by this vette

"I suspect the primary supply for the ignition coil in the start mode is some how sensitive to heat and will not conduct there by not allowing any power to the coil."

I am not too well up on cars but do all my own basic servicing.
I am afraid to give my TR6 to any mechanic as if they start messing with the PI fuel injection system its a ship to the UK job to get fixed.

Andy Blackley
03-19-2006, 04:36 PM
I highly recommend that you ask for asistance from the gents on the TR6 Forum at the TR Register in the UK: https://www.tr-register.co.uk/
They deal with PI daily, and surely will have an answer.

03-19-2006, 07:33 PM
Al, I donít know any thing about the PI models. But you should be able to check the primary side of the coil (the low voltage side) and see if it is getting any voltage. If is not getting any voltage at the primary side of the coil you need not change coils as you will not get the high voltage out of the secondary side of the coil. When you car is hot, will it car start when pushed?

Some Triumphs supply the coil with 12volts only when cranking and then drops to less voltage when running giving a very hot spark for cranking and less spark for running. This 12v to less voltage is a function of the ignition key in the start position vs. the run position. If it will crank when pushed, I think you will know what sub system is giving you problems.

03-19-2006, 08:49 PM
Wasn't that one of the noted problems of the original Lucas PI system? If memory serves, that was one of the single largest gripes, and I can't remember the fix.

03-19-2006, 09:58 PM
You're post certainly seems to point to an ignition problem since you have no spark and you've pulled the plugs to check there is fuel on the end of them, so let's assume it's an electrical issue. Do all these checks when the car is in it's no start mode.
1) Check the points (assuming it's still on points and not electronic) are opening/closing by putting a multimeter (set to measure resistance) on the small wire coming from the distributor (temp disconnect it at the coil. As you crank the engine the meter should cycle between zero and full scale, if it stays at either zero or full scale then the points are your problem area.
2) Another area of problem is the condenser inside the distributor (the cylindrical thingy with a wire attached) this can fail giving the kind of problem you are encountering. I would change that as a matter of course just to eliminate it.
3) check with the multimeter set for +volts DC whether you have power at the +ve (or SW) connection on the coil with the ignition key in the CRANKING position. You should have FULL battery voltage there, about 13.8volts, anything less might mean the ballast resistor is shot as someone mentioned above.
4) Substitute the battery fo a known good one just to check.
5) check the continuity and terminals on the low voltage wires to the coil and from the distributor, they're known to crack and fail from heat/vibration.
6) Check the distributor cap and HT wires (particularly the one to the coil) replacing these might be the only sure way to check them.
7) Check the condition and gaps on the plugs, shud be 25 thou.
8) Last thing to chek on ignition is the timing (although if you have no spark it won't help), if all else is correct, try rotating the distributor about 5 degrees either way and see if you get anything better.
9) If it's no better then start looking at the PI

Let us know how you make out with it and whether you got it back from the pub allright. /ubbthreads/images/graemlins/wink.gif

03-20-2006, 10:59 AM
You didn't say whether it turns over when it's hot. If it turns over and starts when cold, but will not turn over when hot. Your battery is beginning to fail.

03-20-2006, 11:08 AM
wait a minute, im confused here is it or is it not the pi model? if so they had a problem with fuel vaporization in the lines, if not then im sure it is a simple problem with an easy fix. let us know

03-20-2006, 09:00 PM
If it is a PI, it could be fuel vapourization in the petrol pump with hot weather. I know thist was always an issue with our 2500 PI sedan. Used to keep a jug of water in the boot to pour over the fuel pump and cool it down on those hot days. Crude but it worked!

Andy Blackley
03-20-2006, 09:07 PM
I can verify thats its PI. Alfasudcrazy has posted on the TR Register, where they are a bit more knowledgible than most of us on matters PI: https://www.tr-register.co.uk/forums/index.php?showtopic=6694