How to clean and test MFI injectors?

[Schiefer]

A couple of months ago I sent my old injectors to the only shop in Norway I know has experience dealing with MFI injectors.
They looked like this when I sent them and looked the same when they came back.



I was a little surprised because I had expected they would clean them using ultrasound. Called to find out why and they told me it was no use cleaning MFI injectors in ultrasound because it is a mechanical injector and you would not be able to clean it inside because you cant keep an injector like that in open position during the cleaning. Is this correct???

They were tested for opening pressure/ leaks and a visual judgement of spray pattern in the split second they open. Is this good enough and the way it is done in the US also??

Thanks.

[Mr9146]

To answer your question: It doesn't matter what they look like as long as they open at the correct pressure and atomize the fuel properly.

Here's what I do (just did yesterday on a 69E, in fact): I soak the really bad ones in mineral spirits for a few days and them use a Bosh injector tester/cleaner (filled with mineral spirits) to get 'em working again and make sure they atomize correctly.


You need the tool or some facsimile thereof because the opening pressure is so high that blowing through them with compressed air will get you nowhere.

Or, you could spend a heap o' cash and buy new ones. And let me tell you, NOTHING beats a brand new set of injectors ... N-O-T-H-I-N-G.