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I have a 93 F150, it's slow to start up... The starter turns the engine just fine, it just takes about 3-4 times longer to start than should be expected, sputters then smooths out and runs perfect with plenty of power from there. My thoughts are the fuel pump? (allowing the fuel to drain back to the tank) I would like to hear others opinions before running out and buying a fuel pump? It's a the fuel injected 300-6, Thanks...
Our '88 with a 302 does teh same thing. I think it's the computer catching up to the signals... It stumbles for 5 seconds or so then smooths out and all is good.. It can take a lot of cranking to start sometimes too...
Check your fuel pressure.
Turn the key on a few times but dont start it. It should be about 55psi.
Running it should be around 50 I beleive. then pull the vacuum line from the fuel pressure regulator, fuel pressure should go up to 58 or so and there should be no gas presesent in the vacuum line or port on the regulator. Replace regulator if you see any.
Lasty turn off the engine and the pressure should hold within 5 psi for at least 30 seconds. If it doesn't you have a leak somewhere, possibly an injector.
hey all new to the forum. exact same troubles, 91 F-150 302. hard to start [after sitting], cranks a LOT, stumbles for the first while then smoothens out, Hitches a little sometimes on the road..NOT always when it does "hitch" let off the petal a bit and she pulles better., stumbles at low rpm, more so when cold. After "she "sits a couple of hours I have no pressure in the fuel rail is this normal?. I have already changed the fuel pump regulator, filter, and reg tune up...plugs wires cap button, airfilter etc. any suggestions?
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yeah I was going to say the pump. The way I know to test it is install a fuel pressure gauge. and let it sit over night. It should still have pressure on the line in the morning. if not than the oneway check valve in the pump could be bad. so you have to crank on it awhile to get the fuel back to the engine. witch is also why it would run bad at first.