More starting problems - sorry guys

[tunnyx]

Right, after getting its started last weekend I decided it'd be worthwhile buying a new dizzy, leads, condenser and rotar arm. Jack, in his infinite wisdom decided he'd change things over whilst I wasnt around.... and now it wont start again. He changed the leads and dizzy cap (but not the condenser/rotar arm)

So far, to track down whats gone wrong:

I've checked for spark at the plugs - none
I've looked for a spark at the points but nothing.
I've separated the King lead from the dizzy and I've clamped this to an engine bolt.

No spark from the king lead when engine being turned over, but I do get a spark when the ignition is turned off (nothing when I turn it on, nothing when being turned over, spark when ignition gets switched off).

I've then tested for voltage at both contacts on the coil cap. The right hand side one reads 12v whether ignition is on or off. The left side reads 12v when the ignition is off, but 0.4v when the ignition is on. That just doesnt seem right to me at all.

Any advice on what to check next?

thanks

Mark

[izzi]

Hi,
I would disconnect the battery until you get advice.
I have a son that is just like yours, As I suggested before, "you should let him learn by his own mistakes" even if it takes a few years. It also keeps him away from fixing other things !

My son has just saw me write this and says he not like that ( I wish )

Good luck

Roy.

[tunnyx]

Lol Roy - yep, I think they're two peas in a pod by the sounds of things....

[izzi]

Hi,

Sounds like the the ignition wire the wrong way round, however bmcecosse should around shortly to give best advice regarding the electrics we hope.

Best of luck.

Roy.

[autolycus]

The "spark only when you turn the ignition off" sounds as though the points are permanently closed or the the lead to them (probably inside the distributor, where it attaches to the points) is shorting to earth.

But the coil voltages don't make much sense to me. Would you check them again, please, but distinguish between the two terminals on the coil by referring to the lettering on the coil (could be + and -, or SW and CB) but, even more important, by the colour codes of the two leads. The one from the coil to the distributor should be white with a black tracer. Is it?

Which terminal of your battery is connected to earth (the car body)? Are you measuring the voltages between this battery terminal and the coil leads?

When you measure voltages at the coil, do it a) with the points open and b) with the points closed.

Let us know what you get, and we should be able to take you through the next steps.

Kevin

[tunnyx]

The "spark only when you turn the ignition off" sounds as though the points are permanently closed or the the lead to them (probably inside the distributor, where it attaches to the points) is shorting to earth.

Turning by hand I can hear the faintest of 'spark' from the points

But the coil voltages don't make much sense to me. Would you check them again, please, but distinguish between the two terminals on the coil by referring to the lettering on the coil (could be + and -, or SW and CB) but, even more important, by the colour codes of the two leads. The one from the coil to the distributor should be white with a black tracer. Is it?

Not sure what I did originally but having re-tested this there is 12v between the SW/CB points (when the points are closed) and 0v when the points are open

Which terminal of your battery is connected to earth (the car body)? Are you measuring the voltages between this battery terminal and the coil leads?

Its a positive earthed car

Let us know what you get, and we should be able to take you through the next steps.

Cheers Kevin

Mark

[bmcecosse]

How can there be volts when the Ignition is OFF??? This is madness....... There is a WHITE wire that feeds the coil - this wire only has 12 volts when the Ign is ON. Disconnect it from the coil - and please measure it's volts (relative to a good earth point) both with Ign ON and then OFF. I do suggest your son should be encouraged to take up stamp collecting - something far far away from anything to do with cars or electricity.............

[tunnyx]

How can there be volts when the Ignition is OFF??? This is madness....... There is a WHITE wire that feeds the coil - this wire only has 12 volts when the Ign is ON. Disconnect it from the coil - and please measure it's volts (relative to a good earth point) both with Ign ON and then OFF. I do suggest your son should be encouraged to take up stamp collecting - something far far away from anything to do with cars or electricity.............

Hi Bcme - we're learning as we go, and I appreciate the help we're getting - I think you've misread what I've said though (I didn't explain it particularly well).

When the ignition is 'on' there is no spark from the king lead (when clamped but separated by some rubber) to the engine block. No spark occurs when the engine is turned either (whether by hand or by motor). Upon switching the ignition to the off position, a single spark occurs.....

In our case the 'feed' to the coil is yellow (on the SW terminal) - I suppose it could just be a white wire that's rather discoloured. Yes it has 12 volts when the ignition is on (in my earlier post I've said I've got my original test wrong).

As I say, we're learning - I've got a small amount of experience in cars, but I'm no engineer (electrical or otherwise) and my son is 17 and learning - please bear with us. If I wasn't stuck I wouldn't be on the forums - I've already studied the workings of the ignition system and cannot see where the fault is, hence my queries today.

Just to expand a little further:

1 - I've tested for continuity on the sw/cb terminals via a test lamp - ign on = light on, ign off = light off. Thus the coil appears to be fine.

2 - I've tested for continuity from the cb terminal to the connection on the dizzy - again, all fine, on = on, off = off

3 - I've tested for continuity from the coil>dizzy connector through to the moving point and again, all seems fine.

4 - I can hear the faintest of 'spark' on the points when I turn the engine slowly by hand, meaning there is a feed running through the points

But, I cannot get a spark from the king lead, except for a single spark when I switch the ignition to the off position - I only get one spark, right on cue with the switching off of the ignition.

It all seems to smack of a bad earth but everything else electrical on the car works fine (lights etc) - hence its rather confusing me. Kevin's thought of a bad connection made sense but having tested all the LT parts and them all seeming to be fine, I'm stumped still.

Hope I've made sense here - apologies if I've misunderstood any of the workings of the system, hopefully I haven't been an idiot. I'm an accountant/IT specialist by trade so if you ever need any help with either of those I'll be happy to oblige in return

[mike.perry]

I am a great believer in the following rules:-
If it ain't broke don't fix it
Change one component at a time and test afterwards
Don't waste money on parts that you don't need
Always replace the rotor arm that you left on top of the battery

[tunnyx]

Haha - yes Mike - wholeheartedly agree - I've banned Jack from doing anything to it without me. Tomorrow I'm going to put everything back on as it was originally and then work through it logically again.

I'd actually bought a red-top rotar arm - partly because of previous problems that I wanted to rule out & partly because the previous one was an unknown quantity and I'd heard that after market rotars were known to fail. I decided to buy the other parts as I'd noted a few issues with them (leads were a bit long in the tooth, dizzy contacts were a little worn/corroded & a spare condenser isn't a terrible thing to have as a spare)....

Hey ho, you live & learn.

[autolycus]

Not quite sure I've followed all the twists and turns here, and I don't think I've suggested "bad connection" anywhere, so let's look at it from a slightly different approach.

Disconnect the HT king lead at the distributor end, leaving it connected to the coil. Hold or clamp it so that the exposed brass bit or copper wire at the distributor end is 2 or 3 mm from something earthed, like the cylinder head (obviously not touching it)

Disconnect the white/black lead at the distributor end, leaving it connected to the SW terminal on the coil.

Turn the ignition on. Touch the white/black wire to earth (cylinder head again, or the distributor body)

Pull this wire away from the head or wherever. You should get a single spark between the end of the king lead and earth.

The HT lead is the one that could give you a real arm-tingler of a shock if you get too near the exposed end, but you'll get a smaller shock if you're touching the white/black lead when you break the circuit.

I suggest letting us know the result to this point, then we'll take it from there.

Kevin

[beero]

I think Kevin will have you on the right track if you follow his advice. It sounds like you may have the wires and the plastic spacers on the points in the wrong order and these wires are earthing so stopping the points working.
If you get a spark at the coil after following what Kevin suggests then open the points manually and if you get no spark then it must be the wire to the points (or a faulty condensor)
A good way to prove this would be to wire your test lamp with one side to the purple on the fuse box and the other to the white/black going to the dizzy. The lamp should light with the points closed and go off when they open.

[autolycus]

... A good way to prove this would be to wire your test lamp with one side to the purple on the fuse box and the other to the white/black going to the dizzy. The lamp should light with the points closed and go off when they open.

Hang on a bit! Since the OP isn't, as he admits, familiar with electrickery, I was going to spell out which wires are connected and which aren't for this step-by-step approach. If he follows your suggestion with the white/black connected at both ends, we'll all get confused by the result.

Let's see how it develops (but beero has spotted where I'm probably heading)

Kevin

[tunnyx]

Disconnect the HT king lead at the distributor end, leaving it connected to the coil. Hold or clamp it so that the exposed brass bit or copper wire at the distributor end is 2 or 3 mm from something earthed, like the cylinder head (obviously not touching it)

Disconnect the white/black lead at the distributor end, leaving it connected to the SW terminal on the coil.

Turn the ignition on. Touch the white/black wire to earth (cylinder head again, or the distributor body)

Pull this wire away from the head or wherever. You should get a single spark between the end of the king lead and earth.

The HT lead is the one that could give you a real arm-tingler of a shock if you get too near the exposed end, but you'll get a smaller shock if you're touching the white/black lead when you break the circuit.

I suggest letting us know the result to this point, then we'll take it from there.

Kevin

Hi Kevin - right

Disconnect the white/black lead at the distributor end, leaving it connected to the SW terminal on the coil.

Hmm - My lead to the distributor is red (fine), but it leads to the CB terminal, not the SW terminal. The car is positively earthed. I've continued the test on the basis that you meant CB terminal.

I've not been able to get a spark from the king lead. I've tried in several spots on the block and although I did get a very weak spark on my first couple of 'touches' I couldn't recreate them. I've positioned the HT king lead in several ways from several distances ranging from approx 1mm - 3mm and it seems to make no difference to the results - no spark from the HT lead (except for the first couple of tries, when (i think) the spark occurred at lifting off the lead from the block). It was difficult to be 100% sure as the connection from the small lead wasn't ideal and was a bit hit & miss.

Hope that makes sense?

Mark

[bmcecosse]

No - doesn't make any sense. A red lead is for sidelights - should be a white lead to the coil. So someone has been messing about with the wiring at some point in the life of the car. The 12 volt feed (white wire) should be to the SW (= switch) terminal of the coil and the CB terminal should have a white/black stripe wire leading directly to the terminal on the side of the dizzy (this all for a +ve earth car) . So - is there 12 volts on your red wire when you switch on the Ign? Is there a white/black wire from CB to dizzy??

[autolycus]

Yes - brain failure (temporary I hope) - I should have said "Leave the lead to the coil (normally white) connected to coil terminal SW, disconnect the LT lead (normally white/black, but in your case red, at the distributor end, leaving the coil end still connected to the coil CB terminal". etc

I've just tried it on my Midget (identical ignition system). When I made the connection between the white/black lead and the engine, there was a splashy orange sort of sparking if the contact wasn't immediate and positive, then a spark as I broke the connection. Have you had this? As I disconnected it, I would get a single spark up to around 4mm from the end of the king lead, repeatable many times.

If I'd been checking the voltage at the CB while doing this, I'd have expected battery voltage (say around 12.5V) before the white/black lead touched the engine, then 0V while it was in contact, rising back to 12.5 (with a bit of oscillation) when it was disconnected. If the lead from the coil to the distributor makes it awkward to do this "make" and "break", any old short length of wire could be tried, but leave the white/black (or equivalent) disconnected at one end at least. You could connect your bit of wire by twisting it or by using a clothes peg if you haven't got a lead with a croc clip or other connector.

So: are you getting that splashy sparking from the LT lead as you make/break? Can you measure the voltage at the CB terminal when you do this? What we're doing is simulating the points closing and opening, but keeping them, and the distributor cap, out of the circuit for the time being.

Kevin

[tunnyx]

Hi again Bmce

I'll not argue with you there - its a relative mess and really needs a re-wire/new loom, but that'll have to wait.

I've attached a picture below (speaks a thousand words) - hopefully this'll help with the explaination

Yes, the 12v feed (white wire) goes to the SW terminal, and the red whire (see pic) goes to the male spade end connector on the dizzy.

Yes, there's 12v on the red wire (at the terminal on the coil) when ignition is on, regardless of whether the points are open or closed.

Cheers

Mark[frame][/frame]

[tunnyx]

I've just tried it on my Midget (identical ignition system). When I made the connection between the white/black lead and the engine, there was a splashy orange sort of sparking if the contact wasn't immediate and positive, then a spark as I broke the connection. Have you had this? As I disconnected it, I would get a single spark up to around 4mm from the end of the king lead, repeatable many times.

Yes, I get the splashy sparks, which obviously die off when I've got a good connection - however, I am still not getting a good spark via the king lead - I've just re-tried it and still nothing.

If I'd been checking the voltage at the CB while doing this, I'd have expected battery voltage (say around 12.5V) before the white/black lead touched the engine, then 0V while it was in contact, rising back to 12.5 (with a bit of oscillation) when it was disconnected. If the lead from the coil to the distributor makes it awkward to do this "make" and "break", any old short length of wire could be tried, but leave the white/black (or equivalent) disconnected at one end at least. You could connect your bit of wire by twisting it or by using a clothes peg if you haven't got a lead with a croc clip or other connector.

I've tested the voltage at the CB terminal. When the red lead is NOT touching the engine I get a nice clean 12.5 ish volts. Upon clean connection with the engine, the voltage drops to 0v. Release it and it jumps nicely back to 12 volts or so.

I know everyone says its never the coil, and perhaps it isn't in this case, but perhaps its the king lead instead?

[bmcecosse]

So - your feed IS white -and your test confirms the coil LT is ok. So you should then get a spark (it won't be great because there is no capacitor in circuit) when you touch/release the red (should be white/black) wire to earth from the 'king lead' provided it's making a good connection in the top of the coil - please check ! And the HT lead itself is in good condition? We need to do this one step at a time.......

[mike.perry]

Apologies if this has been covered, i just had a quick flip back through and did not see it mentioned.
I assume that brown tube on the HT lead is a suppressor. Have you checked that the HT lead is securely screwed in both ends?
You may be better removing it and using a single length of HT lead