No Spark

Hello James,

For the moment, check to see, with the ignition 'on' if you get battery voltage reading at the coil number 1 terminal.

I will draft you a check list and post that for you tomorrow.

Cheers,

Hello James,

The readings you have had, are fine and OK.  May I ask, from which point did you check for spark?  At the spark plugs, or HT lead on distributor cap?

More tomorrow,

Rakesh

Hello James,

I was looking for my electronic ignition manual but, at the present moment cannot find it.

So, let’s see how I do from memory. You have mentioned that, you have checked for spark at the spark plugs (s/plug). Would you check for the spark at the HT lead, removed, from the centre of the distributor cap? Insert another s/plug in the lead and using a jump lead, connect it to the negative terminal of the battery and the other end at the threaded side of the s/plug.

If you have a spark here, then the fault lies at the distributor cap. Check the condition of the rotor arm and the distributor cap condition for wear on the terminals at top of the distributor body, check the carbon brush, these wear out; I have seen them missing altogether and surprisingly the engine has worked for a while in such conditions. Check the chopper to make sure it is secure and not free- wheeling.

Should everything check out fine with the distributor, then, turn your attention to the green TDC lead from the crankshaft to the ignition amplifier. Remove the amplifier end and set your multi-meter to ‘ohms’ setting. Check the resistance between the inner and outer rings of the plug, no readings indicates a break in the wire.

Remove lead at the amplifier, coming from the distributor. Connect between terminal 3 and 7 of the plug; ohm meter and taking reading. My guess; the reading should be between 400 ohms to 600 ohms.
If the readings are within limits, then the only thing to suspect is the amplifier unit. I will need to come back to you, after I find my manual. There is a test to see if the unit is ‘earthing’ or not but, I cannot remember how to conduct the test.

Going back a step, if you don’t find a spark at the HT lead, test the resistance of the lead, given a reading, the lead could be eliminated, test the coil. You are checking resistance between terminals 15 and 1, any connections to the coil removed. Check resistance between terminal 15 and the coil tower and terminal 1 and the coil tower. There should be no readings between the terminal and the tower. If the coil is ok, suspect the amplifier unit.

You can conduct another test to the coil as I do not know the figures at the moment of the resistances. To overcome that, remove the wire connections to the coil, leaving the HT lead on it and the s/plug set up, to test the spark as described, much earlier. Take adequate length of wire to make a connection between the positive terminal of the battery and the terminal 15 of the coil.

Connect another wire to the negative of terminal of the battery but leave the connection to the coil loose! The next step you want to conduct, is making and breaking connection to terminal 1 of the coil quickly, BUT DO NOT make this connections for long, touch the terminal and break off as quickly as possible, otherwise you could have a ‘cooked’ coil and you may not generate a spark on your test.

I hope this is of some help; I am off to find my manual. I am not sure if the fuel pump relay can have a part to play, depending on models, some have a rev. limiter built into it, whether it has any effect in generating a signal for sparking I am not sure.  I will need to refer to my manual when I find it.

Cheers,

Hello James,

The ignition module is the amplifier, as I have referred to.  Please note, as it is the amplifier or ignition module that, as you have changed, is obviously the problem, if it works, there is no need for you to waste money on a new coil, but the choice is yours.  Note, is the coil you replace for electronis iginiton and upto spec.  Conventional, low current coils are not, so do make sure it is the coil for the vehicle.

It is possible to bench test the modules but it has to be done by specialists.  I would suggest holding onto you module and save that for re-conditioning and keep as a spare or sell it on.  Question is of cost of re-conditioning as opposed to buying one as cheaply as you managed to do - What do you do?

Going back to the mounting of your module; you will have noticed that it had some sticky stuff on the underside of it.  I expect, that the one you bought will have this cleaned off.  As unimportant as it seems, this sticky stuff is important; it keeps the underside clean and help dissipate excess heat, so from you dealer, get some from them, clean the base of your module and apply a fresh, of this stuff. 

I do not know its name, so Good Luck in explaining it your your dealer, should you have a problem, let me know and I shall try and find the part number for you.  Also, good 'earthing' is vital to the function of the module; clean the earthing points, that is the corners of the module and their contact points on the body work, I cannot fully recall, but I think, there is a small earth strap attached to the module, make sure this has good contacts.

Now, is a good time to mention to you, some points of care of your module for its longevity.  Servicing of the spark plugs is important, particularly its gaps, do not let the spark plugs run on larger gaps than recommended.  Additional gaps means the module has to generate unnecessary higher energy, so a spark can jump the additional gap; this, can cook the module if prolonged and excessively large gaps on the plugs are used.  Never, earth any HT lead directly to earth as this has the same effect as large gaps, except the module is fooled into thinking, that because there was no spark generated, it compensates by using more energy to generate a spark, hence cooking its self.  Always use a substitute spark plug so a spark can be dissipated and a correct gap on at that.  To re-iterate, do renew your spark plugs every 12,000 miles or so, do not over extend that mileage by a great deal.

Cheers,

Hello James,

I think you do need to double check the four electrode spark plug is for your engine.  The normal gap is 0.8mm gap of single electrode; the four electrode have gaps that are usually 0.9mm or 1.0mm gaps.  Do not fit resistor plugs either, just stick to what should be.

Cheers,