Hello I'm new to site need some information. I just finished a 89 Jeep Wrangler to M/B OM 617 Swap. I have connected vac pump line to Power brake booster then installed a Tee and when to fuel shut off solenoid and then in to heater control. Everything works as it should. But if you stall the engine and try to restart fuel is still shut off. After about 20 seconds it will restart fine.; I installed a vac gauge in line and and noticed that there is vac going to fuel pump as soon as the vac leaks off (20 sec) it starts.. Do I need to install a check valve or change plumbing ?? Any help would be great. Thanks Trans Yank