First day w/ new Elan, starting problems

Perhaps you guys can give me a hand with this one: newly acquired 69 S4 DHC in the US, with strombergs and pertronix IE/coil.
Car cranks but does not fire. Fuel pump fine. Turns out there’s no spark. HOWEVER: often, when I disengage the starter, I get a ‘stumble’. Then when I turn the ingition key OFF, I get another. I put a timing light on one of the plug wires, and sure enough, I get a burst when I come OFF the starter, and then again (often) when I turn the key off (but nothing when I’m cranking).

Quite strange.

Second question: for how long are we engaging our electric fuel pumps? Do we put them on a few moments before starting and shut them off? Elementary question, I know. Never had one of these before.

Thanks in advance — chris

Chris
The reason for the intermittent firing is that when cranking your supply voltage is drastically (or marginally) reduced,so,the problem is from the battery upstream suspect :-

battery
coil
dizzy gap
plug leads
plugs

or any high resistance connections in the chain

John :wink:

Might be worth doing a static check of the timing to, as I was having problems getting my plus 2 to start and was trying to fire then wouldn’t run and all sorts of stuff. When I eventually got it running with the help of a new set of plugs as one was knackered turned out the timing was at 30degrees instead of 12.

Just a thought, although the rest of the ignition circuit does sound liek the place to start

Andy

Also check the battery and engine earth points…even if they look good, take them off, clean up with wire wool or something similar.
Mark

Could be an ignition switch problem?

Try turning the ignition on and then either starting by pushing the button on the solenoid (if it has one) or by shorting across the main solenoid terminals.

It sounds like you lose the feed to the coil when cranking.

You could also run a feed to the coil thus by-passing the ignition switch which would also test the theory (start via the key)

If you have a ballast resistor fitted I would check the direct feed to the coil from the solenoid.

Alan

Alan
Yes,the ballast resistor,forgot that one it’s a prime candidate…

John :wink:

Chris
I could add to the other experts on the ignition as I have seen this sympthom with a Piranha ignition but I have no Petronix experience.

Most fuel pumps can pump a high flow if your float bowls are empty after a long sit. You can usually hear a slight change is sound from most fuel pumps when the change from pumping freely to pumping against a closed float valve. It’s subtle but with engine not yet running you should hear it. If you have run the car in the last week, there should be no reason to wait at all as there will be enough fuel in the bowls to start. Compare this to using a mechanical pump!
Ken

Thanks so much to all of you. VERY very helpful! Based on all this, I thought I’d focus on the Pertronix module. I pulled the dizzy and removed the module and stuck it into my TR6. Voila, it does the exact same thing.

I move my TR6’s module into the Elan, and now I’ve got spark.

After much cajoling (sp?) I got the motor to fire, albeit not very smoothly, but it ran, and that’s good. I’ve run the battery down, so I’m taking a lunch-break before picking it up again.

Thanks again, folks.

Chris