Hulkson Posted October 29, 2023 Report Share Posted October 29, 2023 Hello everyone, Im a newby here and before the post would like to thank you for the forum. Hi, have VW lupo 1.4 tdi AMF and the car doesnt want to start in the morning also don't hear the sound of diesel when turning the key as before. I cranck the engine and always after around 10 seconds the engine start and runs normal during all day. next day in the morning same story...prb started 3 weeks ago. It feels like there is no fuel pressure during the first crank of the day. Have other issues with the car but not sure if their connect with this morning start. Anyone with sames problems? Thanks a lot! Quote Link to comment Share on other sites More sharing options...
mk2 Posted October 29, 2023 Report Share Posted October 29, 2023 Fuel pump not running... fuel pump relay? Fuel pump fuse? That'd be my guess. Quote Link to comment Share on other sites More sharing options...
tigcraft Posted October 30, 2023 Report Share Posted October 30, 2023 As above!! Quote Link to comment Share on other sites More sharing options...
Rich Posted November 2, 2023 Report Share Posted November 2, 2023 My pd was a lovely person to start the other week, ten second cranking etc. Turns out it was the green temp sensor. Who would have thought that? Quote Link to comment Share on other sites More sharing options...
lupo 1.7sdi Posted November 4, 2023 Report Share Posted November 4, 2023 The VW lupo 1.4 tdi AMF does not have a fuel pump in the tank. Remove the plug from the coolant temperature sensor (see the positioning in the picture) and see how it starts like this (after it starts, put the plug back in) Quote Link to comment Share on other sites More sharing options...
Rich Posted November 4, 2023 Report Share Posted November 4, 2023 23 minutes ago, lupo 1.7sdi said: The VW lupo 1.4 tdi AMF does not have a fuel pump in the tank. Remove the plug from the coolant temperature sensor (see the positioning in the picture) and see how it starts like this (after it starts, put the plug back in) Essentially what I said. Quote Link to comment Share on other sites More sharing options...
mk2 Posted November 4, 2023 Report Share Posted November 4, 2023 What on earth is that whirring sound then (for about 5 seconds), when the ignition is switched on? Sounds like a fuel pump, from the back of the car? Like, what?! And you can hear slushing sounds coming from under the car (fuel return cooler). Are there different versions of the TDi? I've only ever worked on one, to fix brakes. Quote Link to comment Share on other sites More sharing options...
Rich Posted November 4, 2023 Report Share Posted November 4, 2023 Depends what the factory were chucking out that day I suppose. I definitely had a pump on the back of mine. I remember the switch/prime clearly... Quote Link to comment Share on other sites More sharing options...
mk2 Posted November 4, 2023 Report Share Posted November 4, 2023 I dunno then... I do know that all SDI's have no leccy pump. They don't need one as the cam driven distribution (VE) pump has one built in, that can dry suck fuel through the filter to a height of about 10ft. Impressive actually. Working backwards on a TDi from memory, the PDI injector pumps up to injector pressure. The booster or cam driven pump pumps up to about 3bar to supply the injectors. Then there is a filter then the tank. If the booster pump can suck from the tank without a leccy feed, I have no idea. I suspect it can, once there's fuel in the system. But dry??? Maybe that's why "some" have a feed pump from/in the tank. 🤷🏻♀️ Quote Link to comment Share on other sites More sharing options...
Rich Posted November 4, 2023 Report Share Posted November 4, 2023 The system does work without a pump unless it's ran dry. My lupo had a pump, the TT has a pump. When the pump didn't work in the TT it still ran for ages till I lost pressure. Quote Link to comment Share on other sites More sharing options...
Hulkson Posted November 8, 2023 Author Report Share Posted November 8, 2023 Hello everyone, I checked the fuses and all are ok.changed the temp sensor and the car is the same. Fuel filter gave me lots of problems this summer and the car was stopping constantly and after change the filter the car never stopped anymore however it does a ZZZZ sound sometimes. Now I think either the filter return valve is not sealing and air is getting in or like Rich mentions issues with the pump. Thank you for all replys and ideas Quote Link to comment Share on other sites More sharing options...
mk2 Posted November 8, 2023 Report Share Posted November 8, 2023 The fuel filter non-return valve T insert has two 'O' rings, to stop any air getting sucked in. Might be worth checking if they're ok. Or maybe even replace them. @Skezza did a write up on how to do that from memory... Quote Link to comment Share on other sites More sharing options...
Rich Posted November 8, 2023 Report Share Posted November 8, 2023 Filter bypass for a night. Will be reet. Quote Link to comment Share on other sites More sharing options...
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