Triumph Repair: Car doesnt run more than half a mile, compression gauge, triumph spitfire

Question
Hey,
I have a 1979 triumph spitfire this is the first car that I've bought that I'll be doing work to. The previous owner who sold it to me said the car has been siting for 5 years and he never figured out the problem. I checked compression,fire and fuel. Now the problem is the car only starts when it's cold I let it warm up 5 mins or so and I go for a ride less than a 1/4 mile and I'm pushing it back home. The car shuts off and the engine is hot and it won't restart. Car is timed by the way
Thanks!
Anthony

Answer
Hi Anthony,

The three systems, compression, fire and fuel are the only three systems necessary for any engine to run. So when it dies either one or more of the three is missing.

They MUST be tested in the failed mode. (When it has died and will not start) And must be tested in the correct order.

Since it seems to fail in a regular order it is an easy test. Just carry with you a compression gauge (very necessary), a spark plug wrench and a spray can of starting fluid. (all very inexpensive if you don't have them)

First and MOST IMPORTANT is to quickly remove all the plugs and run a compression test (throttle OPEN) you want to see from 125 PSI to 170 PSI with very little difference between cylinders.

Second, put the plugs back in IF it passed the compression test. If it didn't pass the compression test don't bother going any further as you found the problem and that must be corrected before any other tests need to be done. A different set of tests is now necessary.

IF it did pass just spray the starting fluid into the intake and start the engine and note if it keeps running on it's own or requires continuing spray to keep it running.
If the spray will not make it fire off and run then you for sure have an ignition failure and that requires additional testing in the ignition system.
If it did fire off but would only keep running if you keep spraying, then you for sure have a fuel failure and further tests of the fuel system must be done.

This testing procedure is a 100% method to find why a gasoline engine fails to run. Don't skip anything and do it in that order. Let me know and if necessary I will give you the tests for which ever system has failed. Never look for an item failure. Always look for which system failed and then you can look for an item failure.

There are a few tricks of the trade that sometimes help in diagnosis. Does the tach die first or does it coast down with the dead engine? Does it die on the highway or at a stop light? Does it died like someone turned the key off or does it loose power and dies slowly? Does it matter if the throttle is open on acceleration, steady throttle or deceleration?

Let me know,
Howard