Posted 1/13/2021 12:59 (#8748098 - in reply to #8747860) Subject: RE: Still fighting 7800 with intermittent miss
The best way to determine if there is a dead or dying injector, is to loosen the fuel line at the injector while the engine is running, one at a time. The one that doesn't cause the engine sound to change is the suspect one.
Now if the pump is failing, that test will not show anything.
As far as a compression tester, it just looks like a fuel injector with the guts removed. It goes in there with the big 12pt nut as the injector. The injectors in that engine are Bosch KDEL style, so you may be able to cross it to another engine, as long as body size and threads are the same.