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Old 08-24-2004, 07:48 PM
psfred psfred is offline
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Join Date: Aug 2001
Location: Evansville, Indiana
Posts: 8,150
The injectors hold pressure just below opening pressure all the time via the pressure valve on the injection pump, they never go negative at all. There is no way air will travel all the way down the body into the nozzle, anyway -- the overflow lines just collect the inevetable leakage around the pintle shaft in the nozzle (there has to be clearance so it can close).

If you DO get air in there, the pressure valve is bad at the pump or you are getting air into the line at the cap nut or via the injection pumpt itself.

Normal injection volume is 50 microliters (50/1000 mL) per cycle on a Benz diesel and full fuel. To deliver this small volume (about 2 drops, more or less) from the IP to the nozzle, the line must be at near nozzle opening pressure and full of fuel, else nothing comes out.....

Peter
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