Whats your issue first of all, and fault codes if available?

https://www.fordwiki.co.uk/index.php..._Leak-Off_Test

When we used to be changing tdci injectors for warranty on Mondeo/Transit/Focus, we just tested them at idle , 1 min, 4 min and 8 min.

But tbh , a bad injector will fill the small bottles Fords supplied in 1 min if it was a particularly bad one. I cant remember the tolerances now its 15 yrs ago lol, we just used to tell them over the phone our results and they would either advise a new injector or not - which was a pain if you knew in your own mind the thing was knackered or not. - some info on this thread , https://passionford.com/forum/ford-m...test-help.html

https://passionford.com/forum/ford-m...-please-2.html