My truck is hard to crank in the morning. on 1990 Ford E-150

When I go to crank my truck in the morning I turn the switch on and I hear the fuel pump come on.Sometimes it keeps running like its not building up pressure and the truck is very hard to get cranked.When I turn the switch on and hear the pump run and cut off the truck cranks fine.I noticed the other day when I turned the switch to accessories the fuel pump come on.Any ideas would help.Thanks

Asked by for the 1990 Ford E-150
Try this. Before trying to start, cycle (turn the ignition switch) from off to run (that's when all the dash lights come on) 5 times, leaving it in the run position for 5-8 secs each cycle, then try to start the engine. If it pops right off, your fuel pump most likely needs replaced (it's in the tank). If that doesn't create a change, there is an electrical pulse issue between the crank sensor & computer (fairly unlikely), or a failing crank sensor (more likely). There is an outside chance you have injectors stuck open, causing pressure bleed off, as they drain the primed fuel (when you rotate to run & hear the pump) into the cylinders. It can be just one causing the problem, and if you suspect that, & have a multimeter, check the resistance across each injector (should be 10-16 ohms, approx). Usually if you have an injector issue, you will alo have an issue with how the engine runs, esp at idle.
Or have scan test. Unless auto savvy. Profile don't say.
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Have fuel press. test Coolant temp. sensor test,scan test.