Thread: 94 classic ignition starting problems

My guess is that you have wired something wrong, or the replacement dissy has a crook module.

An ignition module can't be tested with resistance. In the case of a module screwed to the side of a distributor, it has two pickup connectors hidden behind the module, and either two or three external connectors. One is +12V ignition supply, also connected to the coil positive. One is the negative switching wire to the coil. There may be a third wire which is an earth shielding wire.

And of course you will see +12V at both sides of the coil. The negative side is only switched down for a short period each piston stroke then released to produce a spark. It is analogous to "dwell" in a points sysem but is unvarying with revs. If the dissy is firing the coil you would see a varying voltage that an oscilloscope or LED tester could pick up.

If you unscrew the module you can measure the pickup resistance, it should be steady until you spin the disy when the voltages produced will make the meter reading swing about.

As for original modules, Lucas or clones, I reject all of them myself and substitute a Bosch BIM024 module instead. There's a thread on it here:

Lucas ignition amplifier replacement by Bosch 024

Start at the beginning as to how I have done it, many times, for varoius people. Bosch is better in this application than Lucas or chinese copy.

And what is a solid state coil? You mean a transformer type? The external appearance of a coil is irrelevant, the internal (primary) resistance is important. You should never use a high resistance points coil on an electronic ignition of this type (Known as a "constant energy" system in LR speak.)

Ignition amp would be a good place to start I would think. Fit a new (or old for that matter) Bosch BIM024 ignition amp. There is a good how to on here from Bee Utey. It's a quick, easy and cheap conversion. Did this on my old 3.5 and went from mediocre yellow spark to a fat blue spark that bloody hurt when I to too close to it...

Edit - Bee Utey beat me by a couple of minutes.. Go with his advice, he is unbeatable on crook LR ignition systems.

Many thanks for the quick response and link to the very comprehensive thread.... The new coil I have was recommended by the new distributor supplier and is an 'electronic ignition coil that will replace Bosch MEC717' - their words. I assume from your response that this is OK to use? I will get a Bosch ignition module as you suggest and see what joy I get. There are also 3 other wires attached to the dizzy that come from the main loom beyond the ignition module connection. Am I right in thinking that these are simply the tacho connections or do they have anything to do with the ECU? There is a single white and 2 blue and white wires. On a side issue is there a way of ensuring you are on the right TDC other than taking off the left rocker cover as I seem to remember it could be on TDC (on crank pulley) but be 180 degrees out unless you can se the valves.

Originally Posted by Steve 94 RR

Many thanks for the quick response and link to the very comprehensive thread.... The new coil I have was recommended by the new distributor supplier and is an 'electronic ignition coil that will replace Bosch MEC717' - their words. I assume from your response that this is OK to use? I will get a Bosch ignition module as you suggest and see what joy I get. There are also 3 other wires attached to the dizzy that come from the main loom beyond the ignition module connection. Am I right in thinking that these are simply the tacho connections or do they have anything to do with the ECU? There is a single white and 2 blue and white wires. On a side issue is there a way of ensuring you are on the right TDC other than taking off the left rocker cover as I seem to remember it could be on TDC (on crank pulley) but be 180 degrees out unless you can se the valves.

Your coil should be fine.

A reminder you will need a heatsink for the Bosch module. A modest chunk of 4-6mm alloy plate or cast alloy, well anchored to the body metal will be needed.

Plain white wire is the +12V feed from the ignition switch. It feeds power both to the coil and the module. Don't try to leave home without it connected.

White/blue stripe wires are for the ECU to recognise engine rotation, in lieu of a crank angle sensor. They connect to the negative coil connector with the module's switching wire. Use your multi meter to determine the wires connection from the module to the coil. (and match the colours)

Find no.1 TDC by removing no.1 spark plug, apply a piece of heater hose and blow in to the cylinder. If the valves are closed you won't get any noticeable flow of air. Try it a litttle each side of TDC and air will blow into the intake/exhaust if you are 1 rotation out.

Your tacho runs off the back of the alternator, nothing to do with the coil. this makes the tacho compatible with the diesels at no extra cost to LR.

Thanks again Bee utey, I am just off to Hitech in Sydney to get a BIM024 which I will fit later today and let you know how things go, fingers crossed!

To test no1 TDC firing, get about 30 degrees before TDC, stick your thumb into No1 ( naturally with spark plugs out) and turn the engine with a socket. If on TDC firing you will feel air pressure pushing your thumb out.
Regards Philip A

Thanks for all your very helpful and encouraging responses. Fitted a BIM024 and MEC717, got the timing right and it still wont fire. It almost catches and then just turns over without a sign of firing. I have just about got to the end of my patience with it so it is off to the LR garage tomorrow. I will let you know what the outcome is.

Originally Posted by Steve 94 RR

Thanks for all your very helpful and encouraging responses. Fitted a BIM024 and MEC717, got the timing right and it still wont fire. It almost catches and then just turns over without a sign of firing. I have just about got to the end of my patience with it so it is off to the LR garage tomorrow. I will let you know what the outcome is.

That's no good mate. Did you have a nice fat blue spark after the ignition mods?