Lumenition MS 3 coils and magnetronic

[sclemow]

Hmm, this is starting to confuse me. I spent a long time going through the electrics, I have remade the king lead, which looked to have a suspect connection into the coil, changed the coil for other secondhand ones, cleaned the block to distributor to check that there is a good quality earth for the magnetronic and it's still a pain in the a*se to start when it's cold, with no discernible change in symptoms.

I've also been right through the solenoid, starter motor connections and earths along with fitting new plugs. The distributor cap and rotor arm have done less than 3k miles as have the leads and look in good condition.

It doesn't seem to want to attempt to fire unless it is turned over for a 'very' long time. Then once you get it to cough a couple of times it normally starts.
This is why I have been looking at the electrics.

The choke levers (It's on twin H4's) are moving and appear to be working, although when it does start it seems to want to start with no choke after the choke has been pulled out for a while.

The car has been set up on Steve Harris's rolling road less than 500 miles ago, and runs very well when started. It also starts fine when warm.
There is definitely something wrong, but I am running very low on ideas.

Anyone got any ideas?

[ianh1968]

Does it have an electric fuel pump?

The mechanical ones only pump when the engine is spinning, etc...

Are the carbs fully primed with fuel when you are trying to start from cold?

Ian

[sclemow]

It's got a solid state SU pump, the plugs are wet after turning it over and the float chambers are full so it's definitely getting fuel.
Cheers
Simon

[ianh1968]

I have a "tarty" 123ignition/Tune distributor...

When I had too much advance at the 0-1000RPM point,
the car was a bugger to start. From memory, going from
about 10 degrees back to about 8 degrees made a lot of
difference to how it started.

(We all know about timing, with the recent threads etc,
And yes, I know that suggesting specific figures is not
ever a good idea... Disclaimer: Go to a dyno)

Have you tried "buggering about" with the timing... ?

Ian

[ianh1968]

... sorry, another possibility...

If you have just fitted some kind of electronic switching
instead of the points, I read somewhere that this can cause
the advance curve to become slightly retarded...

Maybe it needs re-configuring?

Ian

[dklawson]

Since you have an electric SU pump I have another suggestion for a test.

Next time you want to start the engine (from cold and before using the starter) disconnect the power wire to the pump. If it starts easier with the pump disconnected you may have a float valve leaking or out of adjustment. Those wet plugs may be saying you have too much fuel.

[sclemow]

Thanks guys, both interesting suggestions, I'll try them.

For info, the magnetronic has always been fitted to it for a long time and it's been set up with it on the dyno.

Cheers

Simon

[Smiffy]

I have a "tarty" 123ignition/Tune distributor...

That explains a lot