No sparks

[EEED]

I have just replaced the coil, distributor cap, HT leads and rotor arm without disturbing any other components and now I cannot start the car. There are no sparks, so working back through the system I have checked the HT lead from the coil and there is no spark when I removed if from the distributor cap, and no LV current across the coil.

Could it be that the contactless ignition module fitted 12 years ago has failed? The LV leads to the coil come from the ignition module. How can I test it?

The sequence of events leading to this was: replacement of coil - the car ran Ok with the old leads, cap and rotor arm but I subsequently found one post in the cap was quite eroded, so I replaced the cap, leads and rotor arm after which it won't fire up.

The car is a 1966 S3 fitted with an alternator and converted to negative earth, as well as the contactless ignition system. The latter was fitted 12 years ago the alternator conversion was done 5 years ago, both by a local Lotus specialist.

Any thoughts? I have checked previous posts that have been of help, but I need to check if I have missed anything.

All help gratefully received.

Thanks in advance.

[TBG]

I have had new rotor arms fail in the past. Red ones from Bosch last for ever. D

[alan.barker]

What's the resistance of the new Coil i hope it is 3ohms.
If too low resistance you have just killed your "hall effect" module.
Also don't leave Ignition on without Engine running
Alan

[Andy8421]

Youv'e gone the right way about working through the system.

If there is no power to the coil, then no point worrying about anything else until you have that fixed. As Alan mentions, some contactless modules specify a minimum coil resistance, or you can fry the module. Probably worth checking to see if you find out the requirements of the module and the resistance of the new coil.

Having said that, you can still checkout what you have. Most modern (and a 12 year old module is modern) will power down the coil after a period of inactivity to avoid cooking the coil and the module if the ignition is left on with the engine not running. So just placing a volt meter across the connections on the coil won't tell you all that much.

Unless the wiring has been hacked about, way power flows to the coil is from the ignition switch, via the rev counter to one terminal on the the coil. The other terminal on the coil gets grounded intermittently by the points or by the module and it is this that creates the spark. The module usually connects to both terminals on the coil, the connection to the 'powered' terminal on the coil powers the module, and the connection to the other terminal allows the module to provide the intermittent ground.

First step is to check you have power to the 'powered' terminal on the coil when the ignition is on. Measure the voltage between this point and a decent nearby earth (the engine is a good choice). The powering cable is usually white, and there should be two connections to this terminal, the other goes to the module. Usually marked + on the coil (or SW on old coils). Second check is that there is an intermittent earth to the other terminal on the coil (marked - or CB). A low wattage bulb (panel light type bulb) between earth and this terminal should flash on and off when the engine is turned over on the starter.

If you haven't got power, then you need to chase that down, if you have power but no flashing bulb, you need to check the wiring, and if good, think about a new module. There is always a slim chance the new coil is a dud, so if the bulb doesn't flash, you could substitute the old coil and and see if it makes a difference.

[EEED]

Hi all,

Thanks for the very useful replies.

D - the new distributor is red and marked 'Distributor Doctor' so OK, I think. (That company have been mentioned on this Forum as being distributor specialists). But I will try the old one again just in case.

Alan - The new coil is between 4 and 5 ohms measured by my newly purchased mutimeter. The problem occurred after the new coil was fitted and the car has run about 100 miles since, so I think the coil is OK

Andy - The feed from the rev counter goes to the negative terminal on the coil and so does the black wire from the module. The red wire goes to the positive terminal. (Does it matter which way round they are?). I have tried the tests you suggest but so far, no power. I'll try again to double check.

Thanks again

Paul

[Craven]

There is no mention of a White wire that provides the 12volt + feed to the coil, have you left it off?
It belongs with the red wire on the coil.
FWIW

[EEED]

Hi Craven,

Thanks. There is no white wire. The feed from the rev counter is black and yellow. It was added when the alternator was installed and the car converted to negative earth by the specialist who did the work.

Paul

[RichardS]

Paul
In case you haven’t seen my issues with non sparking here is the discussion
viewtopic.php?f=38&t=49466&p=359622#p359622
Covers testing the various circuits
Have you checked the connections at the ignition switch?
Richard

[Andy8421]

Hi all,

Andy - The feed from the rev counter goes to the negative terminal on the coil and so does the black wire from the module. The red wire goes to the positive terminal. (Does it matter which way round they are?). I have tried the tests you suggest but so far, no power. I'll try again to double check.

Thanks again

Paul

Paul, I think we may have found the problem. Assuming you have the Pertronix Igniter module (DD supplies these), then the coil should be wired as follows:

Black wire from the module to the - terminal on the coil
Red wire from the module to the + terminal on the coil
Feed from the ignition switch / rev counter also to the + terminal on the coil

From your description, you have the feed from the ignition switch / rev counter connected to the wrong terminal on the coil. If you will excuse the pun, this may have been be terminal for the module, but you might get away with it. Swap the feed wire over to the + terminal and try again.

Andy.

[EEED]

Hi Richard,

Thank you. Yes, I did glance at your thread a couple of days ago. Will investigate it further. My next step is to check the ignition switch on my car.

A few years ago, I purchased a set of Magnecor leads but they didn’t fit, so I returned them to my supplier after an ‘interesting’ conversation with someone at Magnecor. I wasn’t impressed.

[EEED]

Hi All,

Thanks for the input. I'm glad to say it's now starting, idling and revving sweetly. Road test tomorrow.

It turned out I had missed something.

I checked Richard's thread, Andy's last comment and realised that both Andy and Craven had referred to the live feed via a white wire. There is no white wire on my car but all the wiring diagrams I have checked showed a white feed from the tachometer, so after re-examining it all again, checking the wire from the tach and noting that the engine was turning over - so the ignition switch was probably OK, I decided the power feed must be from a different source. I 'phoned the specialist who fitted the ignition system (Aldon) and the alternator plus negative earth conversion (Max Hurst now of Max 500, previously Lakeside Engineering) who talked me through set up. The power feed is direct from the ignition switch to the positive terminal and had dropped down behind the coil and I must not have been concentrating when I removed it. (Oh dear : ( ) The red and black wires from the ignition module go to the positive and negative terminals on the coil; power the other terminals on positive side.

I tested it as Andy described - all OK - and connected everything up first time. The black and yellow cable to the Tacho is purely for signals to the instrument, not the power feed. I'll daw a diagram for future reference.

It's been a very useful learning experience for me with several lessons to take to heart, so thanks again everyone.

Paul

[RichardS]

Glad you have sorted it Paul
Frustrating initially, but a sense of satisfaction in fixing it!
Richard