The car starts on the nail from cold and runs perfectly .... However. If it's left to stand for 20 mins once warmed up it takes a very long crank to get it to fire up. It always goes, but it can be 10 seconds or more cranking before it fires. I'm pretty sure this is down to vapor lock - is it a known "thing" ?. Does anyone have a fix ?.
BTW, have you done a diagnostic scan? But nothing you have mentioned is too serious, IMHO. Nothing to fret about..though fretting about one's Morgan is a hobby.
I am not as sure as you are as to the cause. Yes, vapour lock is a common reason for hesitation in starting a hot EFI engine. But I have found it is more often a leaking injector. They both create a temporary situation where insufficient fuel and fuel pressure slows a start as the fuel pump brings the fuel rail back up. Also,
a hot engine is harder to start than a cold one as the internals have expanded, tightened and the starter must work harder because of it. As Luddite suggests, modern engines are made to run ever hotter.
There is a cure for leaky injectors. Clean, refurbish or replace the leaking guilty injector (s) which implies you find which it is. Cleaning is often effective and can be accomplished
in situ by professionals. They detach the fuel feed and replace it with a cleaning solution that flushes and unclogs. Low mileage car injectors are especially vulnerable. And storage gums them all up. The cost for professional cleaning in situ in the UK, according to search engines, is 150£. I clean mine yearly at the start of my mogging season, no point in doing at other times and notice a difference. I learned to do it at home as that is more convenient. One merely needs the right interface to the fuel rail and a can of injector cleaning fluid made for the purpose.
Of course, a true injector specialist can do the best job with the injectors out of the car and create a report on each injector flow and its spray pattern. If you are looking for perfection, buy 16 injectors from a break-up yard, send them to an expert to refurbished them and test Then chose from them a set of 8 with the closest matching flow rates and patterns. If you choose, you can then sell the rest for more money than the entire process cost.
BTW, a rad fan should run for no longer than 5 minutes after the hot engine is turned off More runs the battery down and definitely pre-age it. In many cases, I have told moggers, to power the fan from the ignition switch. The reason for running a few minutes after the engine is merely to protect other components (plastic!!) from a too hot engine bay. Did you have melting components?
Lorne
