VZV520

New to list so apologies if already covered (did look!)

1. Cold Start: Perfect
2. Hot Start: Perfect
3. Leave for 15 mins when hot: No start
4. Wait 3 hours: Perfect
Note: Ambient temperature does not seem to matter, its currently 16/22 C but same at 10/12 C.

So far: Spark at plugs perfect, Replaced fuel accumulator, checked that pump runs at 2 & 3 above, no fuel getting to plugs at point 3 above even though system is pressurised.

I'm concluding its a temperature sensor but which one and how do I test or override sensors?

Optimator

Have you connected a gauge to measure residual pressure after shutoff?

jpitman2

Either fuel pump check valve (on pump obvioulsy), or accumulator - in front of RR wheel under the cover. Check this last - some have a tube going to vapour tank in top of wheel arch, others a screw. If there is wet fuel in the tube, or the screw is wet, the accumulator is gone. Its job is to hold pressure to prevent vapour locks from heat soak when shut off. Mine did exactly what yours is doing, and a new pump check valve helped some, but a new accumulator completely fixed the problem.
jp 83 Euro S AT 50k