Jaguar Repair: Ignitio problem, jaguar e type, gasoline engine

Question
Have a Jaguar E Type V12 1974 US version. I have it in Colombia. Is in good shape, runs well. A few months ago I was driving it at say 120km/hour and suddenly engine stalls, back fire from the exhaust, tries to restart asi ti gets slow to a final stop. I trod to restart it and it did start for one or two seconds and then it sips, restart again and the same story. It seems the electricity comes on but inmediatedly cuts off after only two seconds.
What can it be? LUCAS fault? Need advise
Thanks

Answer
Hi Andres,

Symptoms can sometimes lead you to a section of what is wrong but usually symptoms are useless in diagnosis. Testing it the only way to find a problem.

In your case you need to know what goes away, compression, fire or fuel. The three necessary items for a gasoline engine to run.

It is very unusual for compression to return if it was the cause so you can put compression aside for now.

So that leaves you with fire or fuel that is lost after the short run.

This is easy to confirm which by just spraying starting fluid into the intakes just after it starts. If you can keep it running with starting fluid, then you know it is a fuel related problem. (this car has 4 Stromberg carburetors, correct?) However,If you can not keep it running with starting fluid, you know it is a ignition related problem.

To find and pinpoint the problem you first have to ID the problem in a section. Then run further tests on that section.

Ignition is easy to confirm if you find it to be ignition. Just put a timing light on the coil wire (at the distributor if you have the two coil system) Hold the trigger down and start the engine and watch the flash of the light to see if the flash stops before the engine coasts to a stop or does it keep flashing all the way till the crank stops turning. Then move the timing light clip to a plug wire and repeat the test. This tells you if the secondary is getting through the distributor.

If you were able to get it to run on with starting fluid then you need to put a "T" in the fuel line close to the carburetors and a fuel pressure gauge to watch fuel pressure when you start the engine and watch that you still have some fuel pressure when it dies. You don't need much but do need to see some at the shut off time.

Let me know.
Howard