Seat Cupra 6l crank no start

jogiahCupra

Member
Joined
Feb 12, 2024
Location
South Africa
TDI
Seat Cupra 6l 1.9tdi
Hi all ,

I'm new to the tdi world , I own a 20vt and recently purchased a seat cupra tdi ( engine code BUK ).

The cupra is straight piped, GTB2260VZK turbo , engine was rebuilt , stock injectors and internals . It refuses to start when hot sometimes , when cold it doesn't ever start, had to spray a little lubricant in the intake to get it going , idles fine, drives okay , no jerking or bucking , but I can tell it's not boosting at all.

Scanned for codes and nothing comes up , disconnected the cam sensor, still get a crank no start , same if the crank sensor is disconnected with cam sensor plugged in . Loads of black smoke when driving , however I'm expecting this without any boost , that problem i will have a look at after.


The crank no start behavior is very erratic , it will never start when cold (need to add lubricant to the intake to start ), it sometimes starts when warm. I'm led to believe it's a fueling issue , can anyone tell me where to begin diagnoses ?
 

tdi_my live

Veteran Member
Joined
Jul 24, 2011
Location
Germany
TDI
Skoda Fabia
Do you have mode software in the ECU for built-in hardware? Then you could try flashing the serial software and see whether anything changes or not. Then you can exclude the software and concentrate on the mechanics. As always, the engine needs air and diesel, both are available?
 

jogiahCupra

Member
Joined
Feb 12, 2024
Location
South Africa
TDI
Seat Cupra 6l 1.9tdi
I am not sure about the software , I bought the car as is. The fuel side I checked the return line going from the tandem pump back to the filter , diesel was flowing . Should I maybe take out a glow plug or two and try swinging to see if there is diesel going to cylinder ? Air I'm not sure if the actuator on the turbo is opening on start up, will removing the Intercooler pipe help diagnose this ?
 

tdi_my live

Veteran Member
Joined
Jul 24, 2011
Location
Germany
TDI
Skoda Fabia
No, I wouldn't do that. the buk has an electronic shut-off flap. You can check whether it opens and closes. Then the stop screw on the turbo may be open too far and it will stall itself because it is too far. do you have a tester like vcds? There are 2 codes in the file, 00102 and 00105. In the hope that both blocks have not been edited, you can switch over and then see what the start is like.
 

jogiahCupra

Member
Joined
Feb 12, 2024
Location
South Africa
TDI
Seat Cupra 6l 1.9tdi
I believe the flap is deleted , not entirely sure , but It does have an egr delete and a mafless tune. I will confirm later on today , when the car does start and drive , there's no boost from what I can tell , can a possible vacuum leak from the tandem can cause this and the hard start? Or failing veins ?
 

tdi_my live

Veteran Member
Joined
Jul 24, 2011
Location
Germany
TDI
Skoda Fabia
Of course it could be the vacuum pump if it is drawing air. I suspect the software. can you do the test with the transcoding? Test the boost pressure sensor in the MWB10. is the measured pressure and the air pressure identical? There should also be a larger sensor for this turbo.
 

jogiahCupra

Member
Joined
Feb 12, 2024
Location
South Africa
TDI
Seat Cupra 6l 1.9tdi
I'm not too familiar with transcoding ,are there any guides available ? I will have a look at measuring block 10 later on today and update you .
 

tdi_my live

Veteran Member
Joined
Jul 24, 2011
Location
Germany
TDI
Skoda Fabia
this coding is simple. goes into the engine ecu 01. then it shows the coding. probably 00102. You go to encoding 07 and type in the new number 00105. Confirm that and go back out of the SG with. Turn off the ignition for at least 30 seconds after ignition. complete
 
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tdi_my live

Veteran Member
Joined
Jul 24, 2011
Location
Germany
TDI
Skoda Fabia
you have to remember 5 numbers. You can do that, right? You can save it again at any time. My hope is that the 2nd block is series and the car starts well. then we know that you have a software problem with the tuning file.
 

jogiahCupra

Member
Joined
Feb 12, 2024
Location
South Africa
TDI
Seat Cupra 6l 1.9tdi
So I didn't have access to vcds today with the car, what I did do is check the fuel coming out of the filter to the tandem pump , slow stream but should be fine ? I also noticed that the turbo actuator nuts were extremely lose . One more thing Is that the lift pump doesn't turn on when key is on , only if engine is running does fuel come out of the pipe on the fuel filter that is usually connected to the tandem pump
 

jogiahCupra

Member
Joined
Feb 12, 2024
Location
South Africa
TDI
Seat Cupra 6l 1.9tdi
So after much digging around, I changed the injector seals and now she starts on the turn, however , I still don't have any boost, logged in vcds and saw the car is requesting boost as expected, checked the vac line to the actuator and that's fine , the adjustment rod was completely lose ,I put it together as best I could but am not sure on how to correctly set the actuator ,any tips?
 
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