After all 6 injectors popped right at 600 psi on the bench tester we came to the same conclusion that they were probably alright. I put a call in to Bosch looking for the correct opening pressure but they couldn’t tell me, only game me the MB matching part number (0000781123).
This afternoon I cleaned out (with carb cleaner and 130 psi of air) the pipes from the injector pump to the injectors then reconnected loosely, leaving the injectors out of the head. I turned the motor several rotations to bleed the air out and got quite a bit of fuel leaking from the loose compression fittings, so I know I have fuel under pressure at the top of the injectors. (The engine actually started with raw fuel leaking from the fittings down into the combustion chamber!) I re-torqued the pipes to the injectors, put clean paper towels under the injector nozzles and cranked the engine. No spray at all came out of any of the injectors.
On the bench tester all the nozzles had great spray patterns and were within 30 psi of opening pressure (~600psi, which seems awful high to me but not to the diesel mechanic).
With nothing else to go on I pulled the injector pump and checked for contaminates. The pump turns over smoothly by hand, and other than a bit of greasy gunk the pump seems to be clean and has fresh gas running through it. I’m not sure if the cold start valve is currently working but without fuel coming out of the nozzles I think that’s a secondary problem.
Forgive my ignorance, but does 15-18 atm mean 15-18 atmospheres? And does anyone know why Bosch can’t tell me the specs on their part number?
Thanks all!
Don