the engine doesn't start when it's warm

[raferackstraw]

ok first off you need to buy a test guage from ebay or crazy quiffs here in england, im sure they will ship to japan. you need this guage to test the fuel pressures which will then help you to find the cause of the problem. or buy a used metering head from uk or germany ebay and get them to ship to you. for fuel to get to injectors you need to bridge fuel pump relay and lift air flap.

try messaging rubjohnny on here, he will undoubtably have some ideas for you to try

[rubjonny]

as above really! without the proper gauges you'll never know exactly what is happening inside the metering head. once you get some have a read thru these guides:
http://vwtech.no-ip.info/downloads/k-jetpressuretests.pdf
http://vwtech.no-ip.info/downloads/k-jetfactorymanual.pdf