Can anyone help? No Spark problem.

[weblinks]

My Esprit S3 recently overheated and after waiting an hour (and having fixed the fans on and topped up the water) I tried to restart the car. It would not start and on closer inspection I found out there was no spark. I have been told either the coil, or something in the distributor (which had got very hot) has broken under the heat. Has anyone else had this problem after an engine has overheated?

[lotusguy]

weblinks said:

My Esprit S3 recently overheated and after waiting an hour (and having fixed the fans on and topped up the water) I tried to restart the car. It would not start and on closer inspection I found out there was no spark. I have been told either the coil, or something in the distributor (which had got very hot) has broken under the heat. Has anyone else had this problem after an engine has overheated?

Hi,

It's unlikely that an overheated condition caused the problem you are now experiencing. The coil 'lives' in the ignition box and is well insulated against engine heat. The distributor lives on the exterior of the 'cold' side of the engine, and so again, probably suffered no ill effects from any high internal heat which may have occured. You may have touched the distributor and felt that it was hot, but this was probably no more so than in normal operation.

However, that having been said, there is a fundamental weakness on the Lucas 45DM4 Constant Energy Distributor fitted to your car, which is most likely the cause of your trouble. Namely, that the low tension leads which live inside the distributor body and run to the ignition amplifier have a nasty tendency to come loose as a result of poor design and the constant movement as the distributor advances. What happens is that one or both of these leads works loose of it's solder joint. When this happens, the ignition amplifier fails to get a signal from the stator/reluctor signalling it (amplifier) to discharge the coil, creating the ignition spark.

This is not a pleasant situation as you must remove and disassemble the distributor to access and re-solder the lead. Be sure to check all other connectors and fuses first, but ruling out any problems there, a broken internal lead is probably the cause.

To repair, set the engine at TDC (using the push in gear method 'til your cam pulley 'dots' line up). Unbolt the plenum cover (prepare to replace this gasket) and lower the heater pipe which hangs on the lower plenum bolt for easier access. Disconnect the electrical connector coming off the Distributor and the vacuum line (if so equipped). Make an index mark so the Distributor can be re-aligned upon reassembly, this will aid in getting close enough to the true static timing to start the car later. Then unscrew the Distributor retaining screw, located between the 2nd and 3rd intake manifold runners. Pull the distributor rearward until it comes free of the auxillary shaft housing (you'll need to remove the cap to do this). Extract the Distributor taking care to retain the tension spring which 'lives' on the bottom of the Distributor drive shaft.

Now, with the Distributor on a table or bench, unscrew the contact plate holding the reluctor. Once this is removed, you'll see where the two amplifier leads enter the side of the body and also where their contact points are. One or both are probably disconnected from their solder points. Resolder these (use Silver solder if possible as it has a higher heat tolerance, not necessary, just better). Reassembly is the reverse. Remount Distributor and set timing, this should be sufficient to start the car. Car should now start. Set proper timing using a strobe and you're done. Once you are into it, it really is not that difficult a repair, just time consuming and acceses are limited. Good Luck. Happy Motoring! Jim'85TE