I have lost all spark.

[Marcusj1000]

Hello again.

I'm not sure if this should be in the "technical" forum or series 3, apologies if I have put it in the wrong place.

After a few winter improvements to my engine, engine bay and a few other little bits I am now at the point where I am restarting the car again.
After a couple of turns she fired up nicely as hoped but as I built the revs (to about 2000 RPM) the engine cut out suddenly, no misfiring, no noises, she just stopped.

From what I can tell, the previous owner had the re-opus unit fitted. The car also appears to have a non original control box, it is marked up as a CAV 440, I completed 600 miles last year with this system and it performed very well, however I did have intermittent charging problems.

The fact that the engine ran fine for about 30 sec?s before stopping suggests a failure of a component rather than a loose connection where I would expect a gradual failure or intermittent sparking.

I have checked the entire system for anything obvious, all connections look OK. I have also worked through the repair operation manual checks as this is not an area that I am completely confident about. These are the readings I took.
I have battery voltage (13.1) at the SW terminal of the ballast resistor.
I have 3.7 V at the coil + terminal. (manual states 4 to 6V)
I have 1.2 ohms over the coil terminals. (manual states 0.8 ? 1.0)
I have 1.19V on the voltage drop test. (manual says replace amplifier if under 2V)

Ballast resistor (47229A) resistances are as follows:
1) LH mid terminal (SW) to RH top terminal (blue & white wire)-8.2 ohms
2) LH lwr terminal (Start) to RH mid terminal (black & red wire)-1.0 ohms
3) Across lwr terminals (start to white & green)-1.3 ohms.

Resiatances 2 & 3 seem a bit high compared to manual figures.
When I conducted the ?switching action test? I recorded a voltage of 1.2V, the manual states that this should be at battery voltage.

I have a good earth.

So if I follow the manual to the letter it would suggest I need to replace my Amplifier unit AND the Ballast resistor, I however am not convinced. The fact the car was firing perfectly and stopped instantly makes me think it should be a failure that is obvious to see and most of the undesirable readings above are only a bit out (With the exception of the switching action test).

I am hesitant to start throwing new parts at it until I am convinced that I know what is actually at fault. If anyone has any suggestions at all that might help then I am all ears! I am also keen to find out what caused the failure. If I do end up purchasing new parts I don?t want the same problem to happen due to not fixing the initial cause.

I have spent quite a few hours drinking tea and scratching my head with this and I?m all out of ideas!

Thanks in advance for any help, suggestions, advice or teabags.

Marcus.

[christopher storey]

The first thing I would try is substituting the coil with a known good one , if you have one available . If you have not, try testing your coil by putting it on another car and seeing if it will produce spark there

[AussieEtype]

I agree with Christopher - I had a similar issue where the engine would start cold but not run when hot - when cold the coil worked fine but as it heated up - both from power running through it and heat from the engine it developed an internal short and cut the engine.

So change the coil and see how you go - if the problem still exists look to the amplifier.

Garry

[PeterCrespin]

The V12 coil is lower impedance than normal coils and instant failure sounds like an atypical coil failure mode.

I'd look inside the dizzy for rotor, reed switch and/or ferrite rod and circuit board anomalies as that is where the triggering impulses originate. Depends partly exactly which system you have.

[christopher storey]

Peter : the one coil failure I have experienced first hand , on an XK150 in Ireland last year, certainly was instant ! The backfire was enormous and probably could have been heard across the Irish sea . Curiously, it was about the 3rd coil this car has consumed

[Marcusj1000]

Hi,

Thanks all for your responses. I have just swapped the coil to a known working one and tried the Jag one on another car. It appears both coils work fine so I can eliminate that from my fault search.

I have inspected the distributer and there are no obvious problems. I have had a close look at the PCB within the amplifier unit and again there are no obvious visual signs of failure, though I dont know how I can check in more detail or what I'm really looking for. Is there a systematic way of checking this component in isolation to the rest of the system?

To date I haven't needed to employ a specialist to do anything on the car. I'm hoping this won't be the part of the car that finaly beats me! For now I'll keep looking at it and drinking tea.

[Heuer]

Try here: http://www.reopusignition.com/tests.html

[Marcusj1000]

Hello again.

I have been looking at all my components individually and in particular the voltage regulator. Looking inside and after reading bits on the re-opus website I realised that I was incorrect in thinking I had a re-opus regulator and infact it's a standard "long wire" conversion. This is down to a confused conversation I had with the previous owner when I purchased the car.

Anyway, I have been in contact with Paul at re-opus and I've decided to bite the bullet and get their new re-opus H system. Even if my current regulator is not at fault it does seem from what I read on this forum and elsewhere that it is a worthy upgrade.

It should hopefully be with me in 10 days. I shall let you know how I get on when I fit it. If nothing else it will mean that I can eliminate the voltage regulator and pick up module from my fault finding mission.

Fingers crossed.

[D COUPE]

That is a good idea for now and the future. The new Opus is
far far better than the old system and a good investment.

Money cures everything

DC

[PeterCrespin]

Hello again.

I have been looking at all my components individually and in particular the voltage regulator. Looking inside and after reading bits on the re-opus website I realised that I was incorrect in thinking I had a re-opus regulator and infact it's a standard "long wire" conversion. This is down to a confused conversation I had with the previous owner when I purchased the car.

Anyway, I have been in contact with Paul at re-opus and I've decided to bite the bullet and get their new re-opus H system. Even if my current regulator is not at fault it does seem from what I read on this forum and elsewhere that it is a worthy upgrade.

It should hopefully be with me in 10 days. I shall let you know how I get on when I fit it. If nothing else it will mean that I can eliminate the voltage regulator and pick up module from my fault finding mission.

Fingers crossed.

Unless you mean 'amplifier' and nothing to do with regulator, I don't have a clue what you're talking about, sorry. The coil swap result is as expected, Chris's failure notwithstanding. Anecdotal evidence can't match a substantial body of experience across models and decades. Typical coil failure is breakdown when hot, with function returning when cooled. It's not infallible but it's routine enough to point you elsewhere if that's not how hour symptoms play out.

Pete

[Marcusj1000]

You are right Pete, I do mean amplifier. Apologies for that, I have also been looking at the regulator and have written one when thinking of the other!