No Spark ! 1968 build 1969 registered Plus 2 - what next??

[PedroLotusElanPlus2]

First signs of an issue
1. Rev counter reading low - about a 3rd of what the revs were
2. A slight misfire when lifting off
3. Just stopped on tick over - never done that before
4. Restarted but reluctant, drove a few hundred yards to turn around and head home
5. Stopped on tick over again. Would not restart. Pretty obvious no spark - confirmed.
Car has Lumenition optic eye on distributor and HVT electronic kit fitted by Vulcan Engineering in 2016 by previous owner - this is basically a Cambiare AMP on a HVT heat sink and Cambiare oil filled coil. New distributor top, rotor and leads fitted same time from records I have
Tested coil and seemed that LC circuit had a fault
A) replaced coil but with Bosch. No joy but rev counter was reading higher on starter motor
B) spoke to Vulcan and suggested replacing the AMP unless I was getting one small spark in which case it was the optic eye from Lumenition. Ordered both but couldn't see any spark on turning ignition key
C) Replaced the AMP no joy
D) Replaced the Optic eye - pig of a job but managed it without removing the Webers. 40 year old angled screw driver did the trick! Still no joy
E) Checked all accessible earths
E) Replaced the Bosch coil with a Cambiare just in case and it fits in their bracket. the bosch was several mm larger

so couple hours away from the England Italy final and need a good result..
Any suggestions
regards
Pedro

[sprintsoft]

Hi Pedro,

Welcome to the forums

what is the voltage at the coil with ignition on while cranking, it normally doesn't drop below 10v?

Iain

[EPA]

Have you still got the security switch in the glove box?
If so this is the type of problem you can have if the contacts on the switch are going high resistance.
Ed

[PedroLotusElanPlus2]

Iain
Have 12V at coil but only 7.5V when turning over the engine on the ignition switch. Have been told to check the earth on the starter motor - anything else you can think of?

Ed
This was kit car built in Nov/Dec 1968 and registered jan 1st 69. I have all original bill of sale from Ian Walker and factory paperwork and no immobiliser is listed. Glove box has no signs of anything ever being fitted

Regards
Pedro

[sprintsoft]

Hi Pedro,

OK, so a couple of things...

At least you have some voltage at the coil although it is weak, do you have a ballast resistor fitted?

Because you said the tacho is playing up I suspect the low tension circuit is the problem, my next step would be to run a temporary 12v positive feed either from the solenoid or from the battery, to the positive side of the coil, assuming the car is negative earth.

You can try to start it, or spin it over with the plugs out and check for an HT spark.
NB: Remove the temp wire after the test.

Another possibilty is the charge circuit failed, which gradually ran down the battery until the voltage got too low to power the coil or the tacho.

So you can check the battery should show approx. 12.6v if it is fully charged.

Iain

[PedroLotusElanPlus2]

Iain
Think we are getting closer to the problem
Also going to remove the tacho from the equation as apparently that can stop the spark if playing up
Wire from solenoid to +ve on coil. . Neg side of coil to ignition module. .. Then follow the fault finding guide..
Will try tomorrow
Cheers
Pedro

[Bigbaldybloke]

Many years ago my 1967 Plus 2 was fitted with Lumenition optical ignition, it ran well for some time then would randomly just cut out and not restart. After a period it would start again, tried all sorts of things, separate power wire direct to the coil, replacement Lumenition box, still the same, wife breaking down in a roadworks section of the M1 with 9 month old son in the baby seat in the back brought it to a head!
Eventually changed the optical head in the distributor - no more problems!

[PedroLotusElanPlus2]

Thanks for that.
Yes I did replace the lumenition optical eye on the distributor after the coil and then the AMP. Also checked the windmill and rotor cap.
Car is now with a specialist so should get an update today. All earths have been redone and they are going to try copper king ignition lead as the one fitted is carbon. This was going to be my next part swap but outside my knowledge base hence decision to let the professionals take over and get it sorted in a timely manner as the weekend is approaching
Regards
Pedro

[sprintsoft]

Hi Pedro,

I’m sure they know that copper core leads are not recommended for use with electronic ignition.

Iain

[ericbushby]

I didn`t know that.
Maybe that is why my car has been running on copper ignition cable perfectly well for 10 years now. Recently I have also used industrial 50kv HT cable. Mainly because it is the same size, looks the same and because I had some.!
Ultraspark Hall effect module from Ignition Car Parts fitted inside the distributor, About thirty quid. 5k ohm supressor type plug caps fitted.
Eric in Burnley
1967 S3SE DHC

[Bigbaldybloke]

I’ve had copper cables with electronic ignition for years. What’s the reasoning behind the recommendation not to use it?

[sprintsoft]

From the Pertronix site…

Guaranteed for 30 months.
You cannot use solid core (typically copper) spark plug wires with this product. Solid core wires do not suppress electro magnetic interference (EMI) which will interfere with electronics in this product. A suppression style or spiral wound spark plug wires must be used (e. g. Flame-Thrower spark plus wires).

[Bigbaldybloke]

Ok, that’s interesting, no mention of that in the instructions with the unit I was supplied.
Still working except getting the Rev counter to read correctly. Will need to get another set of plug leads it seems.

[PedroLotusElanPlus2]

The experts finally got a spark at 5pm friday and she is running sweet. Will get an update but looks like a dodgy red wire on the lucas distributor but also a rogue earth came into play. Not sure if this was added when all the earths were checked and redone but - It turned out to be TOO MANY earths! There was a spurious one giving false information to the electronics so after reconnecting the broken wire on the distributor still no joy. I’ll get an accurate sequence of ops Monday. Have invested in an extendable mirror to see under those webers!
Thanks for all your input
Appreciate it
Regards
Pedro