OK so I have an AGU engine in my VW T4 Transporter. Everything has been fine for a year but recently when I turn it off when hot and then try and start it after say 10 minutes it turns over but doesn't fire. Never a misfire when running or even stuck in traffic. So something is not liking the heat build up but only on start up. Is there something that only comes into play on start up that could be failing ?