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Electronic Ignition.


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Hello johnw

 

I had an issue a few weeks ago with my 5. Just lost power at 30 mph. Then it wouldn't start but turned over well.

 

Long and short after checking all the injectors, leads etc it was the fuel cut off valve activating. A quick twiddle with it and away I went only to fail a week later, this time though I couldn't hear the fuel pump as well so knew what it was.

 

Remedy, bypassed the fuel cut off valve with a short lead, due to clean it this weekend.

 

Just a thought which is why I posted.

 

Good luck. :)

Edited by MikeThomas
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Hi John,

 

do not try to find a context or explanation for a sometimes occur electric fault.

When you start the car, you stick a key anywhere and turn it to the right, behind is the ignition switch.

 

I had the same problem for 2 years, but never had any doubt about my powerspark.

Finally I opened the 50 years old switch, cleaned the contacts and since that (another 2 years) everythink ist OK.

For you it may me easyer to buy a new one (if this is the reason).

 

To see if 12 V is always on the ignition coil on pin "15" (german Bosch) I connected there a cable

and supply a red LED under the dashboard. Since I cleand the switch (2 years) the LED always lights,

but will not light in case of a fault of the ignition switch.

 

I made this photo for you.

 

Ciao Marco

 

post-13222-0-00743600-1535570708_thumb.jpg

 

 

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I had 2 new accuspark units defect within 100 miles. On recommendation of the supplier I changed from copper to carbon leads. Has been running fine since the last 500 miles. Another positive side effect is that now the degree setting on the timing-light is stable. With the copper leads it was not holding the advance stetting, must have been badly behaved because off a noisy signal.

May also check the voltage regulator is doing its job within spec. High voltage spikes in the primary circuit may ruin the accuspark unit.

 

Btw in my case they became defect during verre hot day. The units let the engine ran for just a couple of seconds everytime when starting.

 

Robert

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I have been running with solid copper leads (albeit with NGK suppressor caps) and Pertronix for about 18 months now.

 

Prior to this posting I hadn't realised that soiid copper and Pertronix are not recommended so rather than carry on chancing my arm, I bought a set of Powerspark leads for £20. I have to say that although the car starts just as easily, it isn't quite as smooth on idle as it was with the solid copper leads, it seems to be hunting a bit.

 

I know there are plenty of more expensive leads out there but bearing in mind the sort of use I give the car, I'm not convinced I want to pay £70 plus for a set of plug leads. Maybe I'll change my mind after a few months running with the cheap ones.

 

Rgds Ian

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  • 2 weeks later...

Hi every one, just an update on progress (or not).

 

Spoke to Martin Jay who sent me some instructions on how to check the Pertronix module.

Low and behold the module is ok but does not work on the car. After much faffing about I disconnected the

ignition lead from the coil and connected a small 12v m/c battery, Well I never the car starts! Re fit the ignition lead

and remove the small battery and it carries on running.

When I check the voltage to the coil whilst turning the starter motor voltage drops to below 10v, is this normal.

I am wondering if the electronic unit will not work at this low voltage.

Car still runs fine on old points system so is this more tolerant of low voltage during starting?

 

Thanks for looking

John

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The enormous current drain to the starter will always drop the battery potential, often to 10V.

 

You are right that a transistorised ignition may not work if the battery volts falls too low, but your original problem was repeated ignition failure after 25 miles or so.

 

I'd check that your charging system is keeping the battery charged. If not, and you stop and faff around for a while :) , then the battery may have erecoverd eniough to fire the transistor again.

 

JOhn

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Hi JOhn,

 

You are quite right about my original problem which I still do not understand, but since then

I have charged the battery to about 12.9v, with no luck getting the electronic system to work.

With the car running at 1000rpm my battery shows 13.8v which I assume is what the alternator

is charging at.

Many thanks for your input.

John

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Your ignition will not work on the cars battery, but will on an accessory one? Have you checked the voltage At The Ignition for each case? Is something, not the starter, drawing volts?

 

The starting drain is only relevant if so severe that it won't start.

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John,

I've recently fitted an electronic unit to my pre-war Riley. Whilst researching I noticed a number of suppliers warned against the use of copper HT leads with their electronic ignition modules. Historically I've never liked the idea of carbon leads - why introduce a high resistance into the circuit? - but given that the suppliers' bumph warned about copper leads 'frying' the unit I've given in to modernity & fitted carbon leads.

 

Are yours copper??

Cheers,

Phil.

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I think the point is there needs to be some resistance in the path from coil to the spark plug tip.

this can be:

Resistive HT leads

A screw on resistor placed half way along a copper HT lead ( either all 4 to plugs, or just from coil to dizzy)

Copper leads with resistive plug caps

Copper leads with plain plug caps, but resistive spark plugs

 

Bob.

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John,

I've recently fitted an electronic unit to my pre-war Riley. Whilst researching I noticed a number of suppliers warned against the use of copper HT leads with their electronic ignition modules. Historically I've never liked the idea of carbon leads - why introduce a high resistance into the circuit? - but given that the suppliers' bumph warned about copper leads 'frying' the unit I've given in to modernity & fitted carbon leads.

 

Are yours copper??

Cheers,

Phil.

Hi Phil,

on my 4A I have been praising the benefits of copper HT leads for a good 15 years or so.

About three years ago I had a problem and so replaced the 'Copper' leads with super dupper stainless steel leads - only to find the original leads were carbon and performed very well.

 

I questioned the wording on the box of the new leads as they say the Stainless steel has great conductivity - NO it hasn't.

In fact it is very poor; less than 10% that of Copper. However it does add the required resistance needed for the suppression.

 

Roger

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However it does add the required resistance needed for the suppression.

 

Roger

I don't think so, the required resistance is in the order of 5 to 10 thousand ohms, stainless conductors will only be slightly resistive in the order of a few ohms

 

Bob.

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Your ignition will not work on the cars battery, but will on an accessory one? Have you checked the voltage At The Ignition for each case? Is something, not the starter, drawing volts?

 

The starting drain is only relevant if so severe that it won't start.

 

Hi JOhn,

 

When cranking the engine I have approx 9.5v at the coil and the car will not start.

If I attach my small m/c battery to the coil with the ignition wire STILL ATTACHED it will not start.

If I attach my m/c battery to the coil but REMOVE the ignition wire the car starts.

 

Although the battery seems fine and turns the engine over easily I am wondering if it cannot maintain

enough power to the electronic ignition whilst turning the engine over.

 

Its doing my head in!

 

Once again many thanks to all who have tried to help.

 

John

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Hi John, sounds like a bad earth either main battery to car body or engine block to body.

What seems to be happening is starter is taking all the current with a big loss through the bad earth. I had a engine block to body woven metal strap which looked ok but had dodgy crimps to the ring ends, if in doubt fit a new one.

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As above earth lead.

 

To test use one car jump lead connected between battery earth terminal and a nice solid bit of the engine, perhaps a lifting eye. Leave all existing wiring in place.

 

Alan

Edited by barkerwilliams
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Hi John, sounds like a bad earth either main battery to car body or engine block to body.

What seems to be happening is starter is taking all the current with a big loss through the bad earth. I had a engine block to body woven metal strap which looked ok but had dodgy crimps to the ring ends, if in doubt fit a new one.

 

Hi Chris,

 

Thanks for that. I did suspect a bad earth at first. When I did a test there is zero ohms resistance.

But just in case I used my jump leads to create another earth from the battery to the engine with no improvement.

I'll have another look though.

 

Many thanks

John

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When cranking the engine I have approx 9.5v at the coil and the car will not start.

If I attach my small m/c battery to the coil with the ignition wire STILL ATTACHED it will not start.

If I attach my m/c battery to the coil but REMOVE the ignition wire the car starts.

 

 

 

I think you have just answered your own question, when ignition wire connected whatever is drawing the voltage low on the main battery is also pulling the m/c battery down.

 

Where are you taking the supply for the electronic ignition module from? Coils will quite often cope with lower voltages but in my experience the ignition modules won't. Have you measured the voltage to the ignition module when cranking? If that's dropping to 9.5V as well than that may be the problem.

 

If the supply is via the ignition switch, then it could be the switch breaking down (not unknown) so just try hot wiring it bypassing the ignition switch and retry and measure the voltage. If ignition switch not the problem then I'd be suspecting starter of either starting to fail and drawing too much current, or bad earths from starter/engine block, try connecting a jump lead from one of the bolts holding the starter on straight back to battery negative and try again.

 

If still no luck, get the battery tested, it may just be failing under heavy drain load.

 

Alan

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Hi JOhn,

 

When cranking the engine I have approx 9.5v at the coil and the car will not start.

If I attach my small m/c battery to the coil with the ignition wire STILL ATTACHED it will not start.

If I attach my m/c battery to the coil but REMOVE the ignition wire the car starts.

 

Although the battery seems fine and turns the engine over easily I am wondering if it cannot maintain

enough power to the electronic ignition whilst turning the engine over.

 

Its doing my head in!

 

Once again many thanks to all who have tried to help.

 

John

 

I did have a similar problem with a TR7 converted to V8.

 

Within the wiring loom, the feed to the coil passed through a resistor when cranking the engine, dropping the voltage to about 8v, if I remember correctly.

This was a hangover from the original 4 pot engine and ignition setup and reverted to 12v when off crank.

 

The Rover V8 electronic ignition system was voltage sensitive and was a pig to start!

Under advice from the Dizzy Doctor I bypassed the resistor within the loom, giving full 12v when starting/cranking the engine.

Problem solved.......

 

I am not sure if this is a feature of the later TR6s but if you connect a voltmeter to the ignition feed on your coil + and disconnect the wire from the - neutral side of your coil. connect the other side of your volt meter to the body of the car (earthing point). Disconnect the starter motor. Switch ignition on and you should find 12v. Turn the ignition key to the crank position and see what the voltage is, if it drops there is a resistor within that circuit which might not be helping?

 

Hope this is a help.

Edited by unclepete
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That is a ballasted coil arrangement and if it did what you describe there was something wrong in the connections because it's supposed to do just the opposite - i..e. apply 12v while cranking and then drop the voltage for normal running to prevent the lower-voltage coil from overheating. Sounds like it may have been connected to the wrong terminals on a relay somewhere so the connection was normally closed rather than normally open.

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Hi,

Spoke to Martin Jay who said 9.5v when cranking may not be enough to trigger electronic unit.

Bought a new battery which drops to about 10.7v when cranking but with no luck.

Fed up now, so will run on points system until my enthusiasm returns.

Many thanks to everyone.

John.

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2 hours ago, johnw said:

Hi,

Spoke to Martin Jay who said 9.5v when cranking may not be enough to trigger electronic unit.

Bought a new battery which drops to about 10.7v when cranking but with no luck.

Fed up now, so will run on points system until my enthusiasm returns.

Many thanks to everyone.

John.

Yet another reason why I stick to points! ;):lol: #oldschool

Stuart.

Edited by stuart
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