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Re: Hot starting problem

Lets start by saying electrickery isn't my best subject. Earthing it will do no harm even if it does no good, it can reduce interference. Your battery position won’t help. The longer the cable the heavier duty it needs to be. As it was build years ago the wiring could have degraded and heat will increase resistance.
Replicate your problem and then link a good battery to master switch. That should show if it is a wiring problem.
Regards Mel.

Re: Hot starting problem

Thanks again for this and what you suggest seems to make good sense. I am going to assume that some wiring on the starting and ignition circuit has degraded and worsens with the heat. I will jump the existing wiring with a temporary new piece to see if I can find where the problem lies. This will take me some time with the other things one has to do in life.

More of a problem I have at he moment is correct registration of the vehicle. I live in France and up to now I have been able to get the French equivalent of the MOT every two years, but I heard recently that the law has changed and this is no longer possible. The current certificate expires on the 20th of this month so I have got to investigate what alternatives are available which is rather a priority.

Thanks for your help thus far and I will let you know what success I have in due course

Re: Hot starting problem

Hi Richard,

I have a Marina based TF that has been on the road for 20 years this year and just wanted to add my thoughts to your problems.

I am not in any way an expert in electrickery but I have found the K.I.S.S (Keep It Simple Stupid) principle works quite well. I am in no way teaching you to suck eggs but my approach would be.

1) Check the simple things first like plugs. Are they in good condition and gapped correctly?
2)Is there a good spark when hot?
2)If it won't start is there fuel in the carb float bowls?
3)You say you fitted the electronic system 16 years ago. Has it been checked since to see if anything has moved or gone out of spec.
4)How old is the battery? Is it still up to spec?
5)If it is not too difficult, switch from the electronic system back to points as a test. Should cost less than a tenner for a set of points and a condenser.
5) clean all the earthing points.
6)When was the last time the tappets were checked?

I hope this helps

Regards

Paul

Re: Hot starting problem

Hello Richard
If you only have a starting problem 'on the key' while hot and yet it will bump start when hot - then you could reasonably rule out problems with fuel feed and also probably the electronic ignition module - problems with these would affect key or bump starting equally.
The most likely causal difference between key and bump starts is the effect that the cranking current has upon the rest of the electrical system, by depressing the working voltage.
It is possible that an ageing electronic ignition module may suffer in this way but I suspect that the coil is a more likely culprit.
Assuming that all 12volt and HT lead connections are clean and tight then the coil itself or the associated ballast resistor (if there is one) become suspect.
An ageing coil may be beginning to run hot, the hotter it gets so does it's electrical resistance increase thus reducing the induced HT voltage to the spark plugs. Couple this with the depressed voltage of cranking may then mean not enough 'spark'
Alternatively the ballast resistor may be faulty. Some coils are 9volt rated and use a ballast resistor for continuous use at 12volts. If this resistor becomes faulty the coil may be operating above it's rated voltage thus overheating and 'cooking' the coil windings.
Things to check
1)do all the connections to coil, resistor, electronics etc and HT leads seem clean and tight.
2)When the engine has been running normally for somewhile does the coil or resistor feel uncomfortable hot to the touch.
Things to try - fit new coil and resistor

Hope this will help and good luck with it
Regards - Chris

Re: Hot starting problem

So I've spent some more time with this problem and have found that if I connect an additional 12 volt battery to earth and the + terminal of the coil it will start immediately when hot.

I have a 45 amp/hour battery mounted in the back of the car which starts the engine perfectly well when cold, when surely it has to do more work to turn over a cold engine than when it is hot.

So....suggestions please with what is causing the problem

Re: Hot starting problem

Hi Richard
Just casting an eye over this discussion though I have not read all replies.
Your link wire which ensures the car starts when warm is probably bypassing the fault, most likely a connection/terminal breaking down with heat. Have you checked the voltage at the coil when cranking hot/cold? I do have some experience with electrickery,Industrial, domestic and automotive, if you fancy picking my brains over the phone let me know.

Re: Hot starting problem

Thanks for your thoughts and I would welcome the opportunity of chatting about this with you on the phone if you can email your phone number and what sort of time you are available.

On further trials today, I now find that I do not need an additional battery to connect to the coil. If I connect a separate cable from the positive side of the car's battery to the positive side of the coil, it starts every time even when hot.

This leads me to believe that there is a cable or a joint somewhere which is putting up too much resistance when hot, and I am by-passing this problem with the separate cable. But which one is it likely to be? And that is where I struggle. I guess it is between the battery and the ignition switch, or between the switch and the coil, but has anyone any firmer idea than a guess please

Re: Hot starting problem

Sorry, contrary to what I said yesterday it does NOT always start when hot with a lead from the car's own battery to the coil (it did yesterday!), but it does seem to start always when an auxiliary battery is coupled up to the coil.

Also, I have checked the voltage at the coil with the ignition on but the engine not running and it is 10/11 volts (my meter is analogue). This reduces to about 5/6 volts when cranking the engine on the key when it won't start. Are these readings about right and if so may the fault lie further downstream?

I would appreciate any help please

Re: Hot starting problem

Hi Richard
With your battery in the 'boot' - the length of cables involved will make volt drop problems the more likely.
Relocating the battery to 'under the bonnet' would probably overcome your problem, without actually find the specific cause.
As Steve says - running a separate cable may be bypassing the cause, but it hard to see what there in circuit that would get hot enough to produce a higher resistance of any significance to be worth bypassing.
It may be that the bypass cable is just helping to reduce the voltdrop at the coil while cranking takes place. Which is exactly what the booster battery would be doing.
The fact that hot starting with the bypass cable only works sometimes while the booster battery always works tends to show how marginal the problem is.

I still have a 'feeling in my water' that the coil may be the problem.
I know you have already replaced this, and that youhave no ballast resistor.
When you have a hot start problem - does the coil feel very hot to the touch ? If it does then this may be the source of your high resistance and would suggest that a ballast resistor may be required.
It might be interesting, if you still have your old coil, to very quickly reconnect this old 'cold' coil and see if you get a successful hot start.

All the best with this knotty problem
regards - Chris