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Poor starting TR3a Discuss.


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My Spitfire 1500 had the same symptoms. Even with reconditioned SU's. Eventually it turned out that the choke cable didn't function properly. You can set all perfectly well: ignition, use colour tune etc as long as the car is running at operating temp. When the choke function (well not really on SUs as we know) doesn't work properly, you can not start a cold car!

 

The good old Saab 96 was mentioned above: mine was outside during the cold winter a few years back. I made sure that the engine ran a little rich. Starting was a piece of cake, even in mid-winter.

 

Menno

Edited by Menno van Rij 2
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We may never know what the cause and solution were.............

....unless Tech Ed gives us feedback

........and he in turn gets feedback from the questioner.

 

I'm not sure that this "Tech Q &A" works for anyone other than the email questioner.

How are we all going to learn from it?

 

Peter

Edited by Peter Cobbold
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We may never know what the cause and solution were.............

....unless Tech Ed gives us feedback

........and he in turn gets feedback from the questioner.

 

I'm not sure that this "Tech Q &A" works for anyone other than the email questioner.

How are we all going to learn from it?

 

Peter

That is actually the point Peter of this section is to throw the question out to the wider membership and then send the link to the questioner so he can try all the suggestions. If I dont get any feedback from the questioner then nothing is really lost as there are still useful suggestions here for everyone.

Stuart.

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Andy asks the same question as I would. You say you clean the plugs, but what state are they in when you clean them. Do they stink of fuel and are wet or is there to next no smell of fuel. If there is no smell I would guess that the choke is not dropping far enough to provide a rich enough mixture to start from cold.

If the plugs are wet through then +1 for flooding.

Rog

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My 4A was always difficult to start, even with an electric fuel pump, tried adjusting/changing everything on the ignition side, double checked the cam was timed right, checked the mixture and float levels, but all to no avail. It would always fire once and then need endless cranking to start.

 

The colder it was and the longer it was left standing the more difficult it was, even with the high torque starter.

 

Fitted a pair of 40 DCOEs over the winter and car fires and idles first tip of the key.

 

I was never so glad to see the end of my SUs that were fitted straight out of the box six or seven years ago.

 

So IMO your problem lies somewhere in the choke/cold starting side of the carbs.

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One of club members was reporting problems starting his TR3A from cold. It just would not start. Turns out that the choke cable outer sheath was extending well beyond the clamp near the front carb and that was limiting the amount of travel of the choke mechanism. I dont think the rear carb jet was moving at all. Once he fixed the cable the car starts from cold at the press of the starter button

 

Stan

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One of club members was reporting problems starting his TR3A from cold. It just would not start. Turns out that the choke cable outer sheath was extending well beyond the clamp near the front carb and that was limiting the amount of travel of the choke mechanism. I dont think the rear carb jet was moving at all. Once he fixed the cable the car starts from cold at the press of the starter button

 

Stan

Sonds like the problem I mentioned a few postings up. Point is, it's less visiable on a TR! A Spitfire's bonnet (hood...) opens towards the front, giving you a fantastic view of the engine when you're trying to sort things out from where the driver sits! So when you pull the choke on a Spit, you can actually see what happens. In my case, I could pull whatever I wanted, nothing happened. I only pulled the outer cable to the back of the dash! The inner cable stayed in place... It turned out that the Moss cable wasn't good from the beginning. Returning to the old cable (with the incorrect knob) I'd kept on the shelf cured the problem.

 

Menno

Edited by Menno van Rij 2
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  • 3 weeks later...

Apologies for the late post on this topic but Paul in post 31 has the answer, I feel. My 3A used to do just this and yes, just pull a bit (a lot) harder on the choke knob and it comes out another inch - bingo - starts with no problem. First choke one inch out easy pull, full choke two inches out two-hands pull. Looking at the run of the cable it is very close to the heater and does quite a sharp bend at that point; just where the flexible part of the cable meets the rigid guide of the choke knob assembly. Enough to make it very sticky given that the inner is a solid wire instead of a braided cable.

 

Rob

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I relocated my choke cable to a new position so that there was a better run and used a small cable end fitting to clamp the outer end in the bracket below the front carb.

 

It seems to work on my 3A. I also have a racing condenser from a mini minor, which is mounted outside the distributor and this one modification makes starting instant when hot. This was the best £30.00 I spent after hot starting problems.

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  • 6 months later...

My1/2 p worth

So many times problems like this are down to coil connections being reversed or simply a worn out battery.

I have found that batteries that turn the engine over quickly and seem ok are simply not letting enough charge go to the ignition system.

That sounds a bit **** but is just my layman's interpretation based on years of suck it and see experience.

Steve

Edited by Stevecross
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  • 3 months later...

If As the 3A does not use a ballast-resistor and coil then I can see the spark being weakened during starter motor operation. Check the spark during cranking. A work around would be to use fine wire electrode plugs which make best use of the voltage available.eg:

http://www.globaldenso.com/en/products/aftermarket/plug/power/features.html

These wire plugs ignite mixtures that are much leaner than normal, hence their use in moderns (along with fit and forget freedom from fouling.That's why they will help starting too. In a stone cold engine the mixture that the plugs has to ignite is actually very lean. The plug can only ingite petrol vapour and in a cold engine only small fraction of the petrol will evaporate to vapour.

 

Or pour a kettle of boiling water over the inlet manifold to get more petrol vapourised !

 

 

Another way to get the best cold-vapourisation is to keep the butterfly closed when cranking. The low pressure between the butterfly and inlet valve will help 'boil' more vapour off the liquid petrol seeping past the butterfly and the mixture will be richer and more combustible. It may be that the choke-cable actuated butterfly opening,intended to raise cold idle speed, is opening too much on those engines that are reluctant to fire and so not allowing enough vapour to boil off.

 

Using summer fuel for winter cold starts is also going to give problems with volatility.

 

Peter

Damn!

Just looked up the Denso Iridium spark plugs that I think will do a 4 cyl TR - Denso IWF20 - Just £8.00 a pop. I am in the old world of spark plugs costing one to two pounds a set or each as it is today - Do you have road test experience of these items in a TR Peter? Should we now be ditching our NGK BP6HS (TR2-4A) and NGK BP6ES (TR5-6 PI) ?

 

http://www.ebay.co.uk/itm/4x-Denso-IWF20-Iridium-Power-Spark-Plug-5378-Set-Of-4-Plugs-Fast-Despatch-/111887507357?hash=item1a0d03df9d:g:7TcAAOSwGotWqM1f

 

Cheers

Peter W

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Damn!

Just looked up the Denso Iridium spark plugs that I think will do a 4 cyl TR - Denso IWF20 - Just £8.00 a pop. I am in the old world of spark plugs costing one to two pounds a set or each as it is today - Do you have road test experience of these items in a TR Peter? Should we now be ditching our NGK BP6HS (TR2-4A) and NGK BP6ES (TR5-6 PI) ?

 

http://www.ebay.co.uk/itm/4x-Denso-IWF20-Iridium-Power-Spark-Plug-5378-Set-Of-4-Plugs-Fast-Despatch-/111887507357?hash=item1a0d03df9d:g:7TcAAOSwGotWqM1f

 

Cheers

Peter W

Peter,

No experience yet, they're sitting on the shelf. My aim is to run really lean at cruise and not to suffer weak sparks under boost: wire plugs should do both. I am always wary of sales blurb but wire plugs are based on sound data, in textbooks and publications. eg thsi on ignting lean mixtures:

http://papers.sae.org/2005-01-1133/

So they should help starting. The carb may be richended but only a small fraction of petrol will vapourise in a cold engine, so the mixture at the plug will be lean.

Peter

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  • 1 year later...

Had this exact problem on an old Vauxhall Velox very recently.

Battery was fine, took forever to churn and start then OK 'til

the next occasion when cold.Replaced all ignition components,

one at a time, regardless of how new they were.

Cap, leads coil condenser, rotor (I didn't bother with changing plugs.

The chance that all 6 were knackered seemed highly unlikely.

Just about to give up when I did get around to changng the perfectly good points.

Voila.Instant success and as a bonus, an irritating mid range, long term

'carburretor' stumble disappeared simultaneously!

Since then starting has been instant.Hot or cold.

And the bonus is, all those ignition parts you tried and didn't help can

now be kept handy for the next occasion.

 

Roger M-E

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Over the last 3 months or so the 4A has been iffy to start. It always does but after a fair bit of cranking.

Last week I was plagued with a spasmodic cough.

 

After some meddling I replaced the spark plugs and lo and behold the coughing has stopped and the poor starting has improved dramatically.

 

Start with the easy items first.

 

Roger

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