E-pump inlet pressure
E-pump inlet pressure
12-25-2020, 12:05 PM
#17
AlanMcR The system does not recover well from any air in the IP. Any air in the IP at startup will get pushed into the high pressure lines immediately. Then you are in for a long crank-fest to push the air out through the injectors. It doesn't matter how quickly the lift pump pushes the air out of the IP, because the air embolism has already been shoved into the injection lines.
As a starting point for diagnosis. Next time, when shutting down the engine, clamp off the tank return line. See if you get the same amount of air in the lines. If the air is gone, then you know that air is getting into the return line. Probably because it doesn't go to the bottom of the tank.
I'll try that although air is trapped in there all the time but after successful starting, maybe clamping will keep more from being sucked in and it should start easier next time. I did fill the tank up till overflow and it still does it so I don't suspect a tank issue. The hard clear lines don't lend themselves well to purge air via mighty vac. Are those lines that hard when new? There shouldn't be much pressure or they wouldn't be plastic, right? Only scavenge and lift pump pressure. I've never had a clear line on my TDI's fail or let air in. I am ordering copper washers and orings for the delivery valves
This post was last modified: 12-25-2020, 12:34 PM by 50harleyrider.
50harleyrider
12-25-2020, 12:05 PM #17AlanMcR The system does not recover well from any air in the IP. Any air in the IP at startup will get pushed into the high pressure lines immediately. Then you are in for a long crank-fest to push the air out through the injectors. It doesn't matter how quickly the lift pump pushes the air out of the IP, because the air embolism has already been shoved into the injection lines.
As a starting point for diagnosis. Next time, when shutting down the engine, clamp off the tank return line. See if you get the same amount of air in the lines. If the air is gone, then you know that air is getting into the return line. Probably because it doesn't go to the bottom of the tank.
I'll try that although air is trapped in there all the time but after successful starting, maybe clamping will keep more from being sucked in and it should start easier next time. I did fill the tank up till overflow and it still does it so I don't suspect a tank issue. The hard clear lines don't lend themselves well to purge air via mighty vac. Are those lines that hard when new? There shouldn't be much pressure or they wouldn't be plastic, right? Only scavenge and lift pump pressure. I've never had a clear line on my TDI's fail or let air in. I am ordering copper washers and orings for the delivery valves
Messages In This Thread
E-pump inlet pressure - by 50harleyrider - 07-06-2018, 06:07 AM
RE: E-pump inlet pressure - by AlanMcR - 07-10-2018, 12:48 PM
RE: E-pump inlet pressure - by Mr.Emo - 07-11-2018, 01:43 PM
RE: E-pump inlet pressure - by AlanMcR - 07-11-2018, 04:08 PM
RE: E-pump inlet pressure - by Mr.Emo - 07-12-2018, 03:25 AM
RE: E-pump inlet pressure - by AlanMcR - 07-12-2018, 11:11 AM
RE: E-pump inlet pressure - by CutWeldDrive - 07-13-2018, 05:19 PM
RE: E-pump inlet pressure - by 50harleyrider - 12-22-2020, 03:47 PM
RE: E-pump inlet pressure - by AlanMcR - 12-22-2020, 04:14 PM
RE: E-pump inlet pressure - by 50harleyrider - 12-22-2020, 04:47 PM
RE: E-pump inlet pressure - by AlanMcR - 12-22-2020, 05:16 PM
RE: E-pump inlet pressure - by 50harleyrider - 12-23-2020, 01:39 AM
RE: E-pump inlet pressure - by 50harleyrider - 12-23-2020, 03:55 PM
RE: E-pump inlet pressure - by AlanMcR - 12-23-2020, 09:56 PM
RE: E-pump inlet pressure - by 50harleyrider - 12-23-2020, 10:15 PM
RE: E-pump inlet pressure - by AlanMcR - 12-24-2020, 03:05 PM
RE: E-pump inlet pressure - by 50harleyrider - 12-25-2020, 12:05 PM
RE: E-pump inlet pressure - by AlanMcR - 12-26-2020, 10:56 PM
RE: E-pump inlet pressure - by 50harleyrider - 12-27-2020, 01:33 PM
RE: E-pump inlet pressure - by AlanMcR - 12-27-2020, 03:20 PM
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