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Hello My 1994 f250hd 4x4 a40d 7.3l turbo will not start when hot. The truck runs fine and starts great when cold but if it sits over 15-20 minutes it takes forever to start. Today i replaced the fuel filter and filled it with Diesel Kleen with no change. There is no smoke at all my mpg is the same the fuel cut soleinod has power with key on.The IP and injectors have about 1000 miles on them.I checked the schrader valve on the filter housing while crankig in have a good stream of fuel with no air in it.
Ok - I was going to say IP but you replaced it. If the fuel return lines are they painted "gray" ? If they are then replace. Check your Glow plug relay for time on when warm when trying to start. It should be on for at least 2 seconds then clicks a few times. Seen where it would work OK stone cold but a warm engine it didn't kick in properly.
maybe the soliniod isn't getting enough voltage when cranking over. back-probe the terminal (solinoid connected) with a voltmeter and have someone crank the engine, see how much the voltage drops from just having the key on. i don't have the spec on hand but i think you need at least 9.4 volts.
How old is your starter? when the starter is in stage failure it will draw more hot then cold and crank the engine slower.. You need the speed to make the engine start..Or the same for your batterys but my bet is starter..also bad connections positive or negitive.. either one..
Also the glow plug system is all new. The batterys are also new I think it maybe be the IP But i do not want to replace it if that is now the problem Thanks Dennis
Is it cranking good when it wont start? is it as fast as it is when it will start? are you giving it a little throttle when your trying to start it? if all that is normal try pouring a little cool water on the ip when it wont start if that makes it go.. then you have found your problem
My guess would be air in the system....I had this problem off & on till I cut and plugged the fuel return line from the filter head and the #1 injector, no problems since.