Triumph Repair: 78 Spitfire wont stay running!!!! ERRR!!!, webber 32, time interval

Question
Hi, I have a 78 spitfire that will not stay running. There is no time interval of when it dies, sometimes it will die right after I start it and others it will be a couple of minutes. It is a stock engine with stock fuel pump but a Webber 32/36 carb conversion and a crane 700 electronic ignition. I thought it could be a fuel problem so I replaced the fuel pump and filter, that did not work. I checked the timing, and cleaned and gap on the plugs, that did not work. I read on another question answered by you that someone was having an ignition coil problem, replaced that and the problem is still there. The plug, rotor and cap are only about two years old and still look new. I also read in the spit and gt6 mag about someone that was having similar problems replaced the battery, so I did that too and guess what... that did not fix it. So the last thing I thought it could be was too much fuel pressure into the carb, so I got a pressure regulator and that did not work either. So now I hope you can help me!

Thanks,

Dave

Answer
Dave,

In order for the car to run you need 3 things... fuel, fire(ignition spark) and time (timing).

If it's starting without outside assistance (starting fluid/ether) then that suggests that the pump is getting fuel to the carb.

So it sounds like that when it's starting you get all 3 of the essentials.

Some questions:

When the car stalls, does it restart immediately?  
Does it take additional cranking to get the car to restart?
Do you need to let the car sit before it will restart?

If the car restarts immediately it suggests that the problem is most likely with the electrical wiring.  Possibly the ignition switch is bad and you only get the ignition contact in an intermittent fashion.   Hooking a voltmeter lead to the coil and watching as you drive when it dies will show if this is the problem.

If when it stalls you need to crank crank crank to get the car started suggests an issue with the fuel delivery system.   Maybe a bad fuel pump, maybe a blocked filter.

If the car will start and then rev and rev then die when you let it go to idle.. then die and need some time before it restarts.. that suggests that the advance mechanism in the distributor is sticking at full advance.  Pull the distributor and clean the mechanical advance.


Cheers,

Jim