FirstGen1991

Afew days ago i went to the store and left truck idling while i went in, came back out and put it in reverse and lost rpm and oil pressure. Cut the truck off and checked afew plugs and the oil, everything appeared to be fine. Tried to crank the truck again and it would turn over but not fire, but it would occasionally hit. Well after trailering it home and tinkering with it, it suddenly stopped trying to turn over and started making a high pitch whine down around starter that lasted about 5 seconds and had a sort of thud at the end. Well i took the starter off and went to the local parts store and it was shorted out and the shaft jumped in and out so i bought another, put it on and still getting nothing. Seems like something isnt getting power. Battery is charged and terminals are tight, all the interior things come on when i turn the key to on. Hope someone can help. -Thanks

j_martin

Other than guessing from your forum name, I have no idea what you're driving, what's been done to it, what yer burning for fuel, etc, so this is just a guess.

You have more than one problem, some probably self inflicted.
1. Probably fuel problem. Could be dirty fuel, out of fuel, leak in suction line, lift pump crapped out, plugged filter, water in fuel, wire loose on FSS, etc.

The squeal (hiss maybe) and thump is probably the intake air heaters cycling, perfectly normal. If that stopped, maybe the primary ignition power is now missing. If the wire fell off the fss, and shorted to ground, it would take out a fusible link, giving you all these symptoms.

Start by checking for power at the FSS. If there, then troubleshoot the starter relay and starter.

The starter motor is good for about 10% duty cycle, ie 30 seconds on, 5 minutes rest and cool down. You probably smoked it by cranking too long. The present problem is probably base power, or you mis-wired something.

FirstGen1991

Sorry bout that, got ahead of myself and left out somethings. Yes its a 91 w250 non i/c. Also when the truck would turn over and not fire it sounded like it wasnt getting fuel, but it would hit ocasionally, replaced starter last night. Has a 1/2 tank in it, and i havent messed with fuel filter yet. Any way to know if lift pump is good or bad? To just quit getting fuel like that while sitting at idle it made me think it had rattled a plug loose. But it would idle fine in park.. Tackling the problem with it not turning over at all is first priority of course. Which is obviously electrical, my fuel filter may be dirty and be the reason im not getting fuel (i hope its that simple) because i havent changed it in awhile.

thrashingcows

Replace the starter relay onthe drivers side inner fender. Could be why your starter is not working.

FirstGen1991

Took my battery to local parts store and figured out it was bad, assuming after a slow charge all night and when i took it up there it only had a 34% charge it may not have had enough power to engage the starter. But even with some jumper cables hooked up it wouldnt turn over. May be the starter relay too. But im gonna get a new battery tomorrow and hopefully itll start.