Milli volts in just a random test seem close enough. Or at least nothing is indicated as being really bad.


As mentioned it is turning out that using the temperature sensing tool is quite subjective because of the slightly different reading angles etc.


This said the right fuel pressure over a really substandard amount does usually make the idle better. In your case I would remove the return line from the injection pump and direct the return diesel fuel into a clear container looking for any air almost first of all. No air? Then reconnect it and close the line off to see what it does to the idle. You will not hurt anything by closing off the return line for a test. The lift pump by design just attains a certain pressure and just remains there.