Modern Vespa

Hi all, just bought a gts300 super that would crank but not start, fuel pump didn't run so I took the cover off the fuel pump relay and held the contact in, the pump ran and she fired straight up. The issue I've got is the relay won't do the job on its own so I imagine its not getting its own power feed I also bought a new relay, same issue, any thoughts appreciated.

What voltage do you have at the relay coil?

Have you checked all the fuses?

The relay ("Fuel injection loads control switch") coil gets 12V from fuse no.2 that's under the seat, and the ground for the coil comes from the ECU.

So check for 12V on the red/white wire. If that's there, then either there's a wiring funny from the ECU, or the ECU doesn't think the bike should run for some reason. It won't be the kill-switch as the starter works.

Manuals at: https://manuals.wotmeworry.org.uk/Vespa/GTS300%20Super/

Thanks Jim I'll give that a go

Hi Jim, checked everything, no ground from ecu as you said so I put a jumper wire from the frame to the relay and everything works perfect now, many thanks Paul.

Be aware what you've done is merely a work-around to get out of trouble. You really should try to find why the ECU is convinced the engine should not be allowed to run.