sorry for the long post in advance but Ive got a 7fgcu45 with the aisan fuel system, twc, electronic governor system. truck will start normally but as soon as you let the key go the +voltage to the lpg solenoids on the regulator drops to 0. if you hold the key to start it will stay running, also if you jump 12v+ to solenoids the truck will stay running. this truck came to my shop with the relay bypassed so when key is on the solenoids on the regulator have 12v all the time with key on. so if you leave the key on it will continue to dump fuel into the intake even if the engine isnt running. so my guess is someone had the same issue im having and instead of fixing the issue they bypassed the relay. i have removed all of the hacked up wiring but now have to fix this problem i have the wiring diagrams for this truck and have traced my problem back to the fuel relay. i have + voltage to the coil side of the relay with keyswitch on and i get the negative to the coil from the ECU but only in the start position. so for some reason as soon as i let the key go from start im loosing that negative. im not sure if the controller is bad or if there is something that the controller is seeing that is making it want to shut off fuel. it does not have one of those engine shutdown system. i have had this exact issue on a 8fgcu25 which turned out to be a tach wire broken at the distributor. i checked the tach wires on this truck and they check good. also swapped ignition coils just to make sure. that did not help either. thanks in advance for any help.