Start problem vw t6 CXHA

[DXX]

Did the correct bleeding procedure tonight, but it made no difference. Took 9 sec for pressure to build up, and no start.

Also tried to bleed at the injectors as suggested by DXX, after that, pressure came up pretty fast and i believe it was closer to a start than before. I will make a new log when starting tomorrow, and bleed at the injectors one more time. I was a bit in a hurry when doing it.

You need two people to crank and bleed at the same time otherwise you’ll be some time

 

[ThorO]

Today the fuel pressure was building up almost instantly after engaging the starter, so I guess bleeding at the injectors got the air out.

Unfortunately it wouldn't start, but its sounds like its almost there. My guess now is that there is air trapped in the injectors, probably because the bleeding before first start wasn't sufficient.

I tried to do the trick i found in another thread to disconnect hpfp connector, and put 12v on the pressure regulator, but it didn't work. Pressure was never above 5 bar, don't know what I did wrong but that would maybe have forced the fuel into the injectors.

Not sure what to do next.

 

[DXX]

Are you sure the injectors are tight and you have full compression? If somebody has put grease on the seals it will have blown out and cause low compression.

 

[ThorO]

Are you sure the injectors are tight and you have full compression? If somebody has put grease on the seals it will have blown out and cause low compression.

I replaced both copper ring and O-ring, kept copper ring dry and had a little oil on the rubber o-ring. Bolt torque 8NM+270 degrees.

 

[ThorO]

Just a short update, It seems like it was air trapped in the injectors, I probably didn't do the bleeding good enough. To solve it, I got hold of 2 used injectors, was able to start and increased RPM and fuel pressure to bleed the remaining 2 original. Then swapped back and bleeded the last 2 injectors. Thank you very much to mmi and dxx for taking the time to help. Most appreciated

 

[DXX]

Just a short update, It seems like it was air trapped in the injectors, I probably didn't do the bleeding good enough. To solve it, I got hold of 2 used injectors, was able to start and increased RPM and fuel pressure to bleed the remaining 2 original. Then swapped back and bleeded the last 2 injectors. Thank you very much to mmi and dxx for taking the time to help. Most appreciated

I’m unconvinced that the VW method of letting the HP system bleed via the leak oil route works, there have been multiple Forum threads where it simply doesn’t work.
I can understand why they like to de-risk work procedures (no fuel spill) and be able to carry them out with the ridiculously placed charge air cooler in position but there’s no point if it only works in theory.
Good it’s up and running.

 

[manfrotto]

This has got me thinking - What happens if you run out of fuel? I assume you would need to do a full bleed of the system, and hope it hasn't damagaed the HPFP in the meantime?