Have 7.3 diesel motor hard to crank on warm or cold day will crank if it has been plugged in overnite we changed glow plug relay and we changed intake heater relay had it in shop at the ford house had injectors replaced and glow plugs changed how do you check glow plugs. ford house was supposed to change them but not sure if they did.

You have some of the injectors that are bad Just had the same problem. Replace all glow plugs and controler check high presure oil pump and injectors and then replaced injectors and now it starts even though the injectors checked good. When heater is not plugged in it would try to start but not the ex. would blow black smoke then plugged it in for 3 or 4 hours and would start up. do the injectors save the greif of plugging it in. You have some of the injectors that are bad Just had the same problem. Replace all glow plugs and controler check high presure oil pump and injectors and then replaced injectors and now it starts even though the injectors checked good. When heater is not plugged in it would try to start but not the ex. would blow black smoke then plugged it in for 3 or 4 hours and would start up. do the injectors save the greif of plugging it in.

check and change the injectors they will over fuel and not let the eng. start. check and change the injectors they will over fuel and not let the eng. start.