OK. Here is the scenerio. I have a 1989 Formula 350 (that has a relatively stock 350TPI) that has had a hard start issue for a long time. When cold, the engine will start up with little issue and run fine. If I shutdown the engine when warm and try to restart, when warm, it will try to crank over but wont start. If I squirt some starter fluid into the throttle body, the engine will start right up and run just fine again. I have just changed my fuel pump and filter (due to the pump dying out recently) and I hear the pump prime when the key is turned on but this hard start problem still persists. Am I missing something simple to check? Please let me know. Thanks, Steve

 

Most likely, you're looking at a heat related failure of injectors. It only takes one or two on each bank to pull down the signal to all of them. Ohm test the injectors.They should test between 12 and 17 ohms. Any that are low are bad and are probably shorting out when hot. Also, just to be sure, check fuel pressure when this problem is occurring to verify 40 psi with the key on and while cranking. The pressure should also hold for several minutes with key on or off after priming. Also, try unplugging the MAF sensor when it wont start then try starting it this way. If it starts, that points to a MAF sensor or circuit problem.