Caddy 1.9 TDI 4motion BLS 2010

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SK2020

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Hello, hope someone could help me out here:thanks: i got air in fuel lines, from the filter housing 2 the HPFP and in the return line back 2 the filter housing. no air is coming from the fuel tank 2 the filter housing.
Symptoms: Loss of power, intermittent fuel loss 2 engine.

Car was filled with gasoline and was driven until it would not run anymore.

Parts changed: All 4 injector, HPFP, Fuelpump in the tank.

NO fault codes.

any suggestions?
 
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HMC

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Hi SK2020,
The obvious question is have you changed the o rings in the fuel lines?
Regards HMC
 
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SK2020

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Hello, thank you for the response. yes i have, changed it for the second time just 2 be sure.
also changed the filterhousing without any effect.

This VW has PD injectors.
 
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ai_Ingo

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Hi, please check whether the supply line was accidentally swapped with the return line on the tank.
 
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ai_Ingo

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Sorry, I just see that you wrote that there is no air from the tank. In that case, I would check whether the socket in the aluminum housing on the tandem pump is tight.
As the pump sucks, air could enter there.
 
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SK2020

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hey, thnx for the response!

checked the socket at the tandem pump. no air leaks there. but what i noticed is that the tandempump is making boubles in the fuel inlet and sending it back 2 the filter WHEN i turn of the engine.
when engine is running, the air is coming from the filter housing and goin 2 the tandempump, and also from the return line from the pump 2 the filter. and when i opened the fueltank filler cap i noticed that it sucked in air. almost like it was vaccum inside the fuel tank.
i also noticed some farting noise coming from the tank.
did a smoke test around the filter housing. it does not look like it is sucking in air from there. same on the socket at the tandempump.


hmmm..:confused:

Any suggestions?
 
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   #7  

ai_Ingo

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Just to be absolutely sure, there is clearly a negative pressure in the tank?
 
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