Ah Bliss, Vroom Vroom...

[billwill]

I seem to have found what was causing my recent problems with my Elan.

A tiny bit of rubber/plastic blocking the petrol feed to one of the carburettors.

I went for a lovely drive around yesterday,

Vroom Vroom...




Mind you she is still reluctant to start when cold & oddly needs me to hotwire the starter solenoid to start.
It doesn't make sense, but empirically that works..

[alan]

Hi ,
i have had this problem with the solenoid on both my lotuses.
The problem is the earth on the solenoid. It is just under one of the fixing screws for it . What i did was put a new earth wire to attached to one of the fixing screws
Alan

[billwill]

Could be, but I was terse on the symptoms.

The solenoid actually works properly and operates the starter motor. A few weeks ago I determined that it would start when I hotwired the solenoid (with ignition ON) but would not start with the ignition key.

This pointrs to dirty contacts in the ign switch in the START postion; there are two contacts, one operates thr solenoid & one feeds the ignion coil via the loop in the rev counter. These symptoms indicate that that second contact is dirty, SO I took out the Ign switch & cleaned it up with RS Switch Contact Cleaner spray, and it seemed ok, VERY Briefly.

Next day. No cold start again, so I decided to add a relay operated by the same solenoid voltage (so it pulls in when the solenoid pulls in). The contacts of the relay feed the battery voltage direct from the main terminal of the solenoid directly to the coil, this bypasses any problems in the ign key switch (in theory). I checked that the relay does indeed pull in.

However it makes no difference, the engine stlll does not start from the ign-keyswitch while cold, but will start if I hotwire the solenoid (which of course also operates the relay). Its an enigma; it shouldn't make any pesky difference...
In essence the sparks are not strong enough while the starter is running from the Ign-key, but are strong enough if I hotwire the solenoid. I don't think this can be due to the earth on the solenoid, but could be an earth problem elsewhere.

============

Since I put in that relay, on another topic here I see that there is a different model of the solenoid which includes a contact that does what my relay does, so I might get one of those and remove the relay and feed that extra contact direct to the coil. One member here mentioned that it is intended to go to the coil on ballast resistor systems. My other possibility is to convert to a ballast resistor system, if I can get hold of a new ballasted coil and resistor.

That will be annoying as I boight a new non-ballast coil recently as part of trying to find out why cold start was so poor.

====
However next actual step is to clean up the engine->chassis earth strap and the battery-> chassis earth strap to see if that fixes the problem.

[wojeepster]

Measure the VOLTAGE at the coil when you are cranking to see if you have a voltage drop somewhere in the system that is causing your no start. You should have very small (.1v)voltage drops everywhere except across the coil where you should have close to 12v

[billwill]

Yes, I know.

There will be some drop though say down to 9 or 10 volts, even on a fully functioning car, due to the very long main battery wires on the Elan 'cos the battery is in the boot and due to the internal resistance of the battery.

This drop is what the ballast resistor system is designed to overcome; the idea being that you DESIGN the ignition coli for say 9 volts, then for normal running you insert a ballast resistor to drop 3 volts from 12 volts, so that the coil runs at its designed voltage.

However during starting you feed the coil directly from the battery bypassing the ballast resistor, so that the coil gets the full battery voltage, but which has dropped down to about 9 volts due to the load from the starter motor. Thus you get full spark power during starting.

========

Ironically I can't at present get a decent voltage measurement accross the coli because I don't have an oldfashioned needle analogue voltmeter on hand. My digital voltmeter might get damaged by the transient voltage of many Volts accross the coil when its magnetic field colapses as the distributor points open. So I've not tried that.