ok so heres one for all of you to work with. ok so i go to start my truck it will start but wont stay running even at half to full on the little skinny pedel. a;most like it was shut off. i cant seem to find anything wrong well that sticks out anyways. then it wont start at all acts like it has a dead battery. so i let it sit for awhile and then same thing all over again. but earlier in the day it ran just fine got me to the parts store, then quits on me. so any guesses?

 

What year? What engine? EFI or carb?

 

fuel pressure?

 

sorry i guess that would help alot... duh.
1984 f-250 carbed 460

 

Assuming you have a DSII ignition (silver sandwich-sized box on driver's side wheel
covering) take that module to an auto parts store and have it tested.

The acting like a dead battery is likely a different problem, though. Explain some more
about this - what EXACTLY happens? Do any lights in the interior or on the dash ever
come on? Does the starter ever engage when turning the key? Do yuo ever hear the
solenoid clicking under the hood? etc. etc. etc.

 

well, ill go to start it and it will staert up just fine, it will run for a few seconds then just dies, like i turned the key off. ill go to restart it, i can hear the solenoid clicking over and the engine wont even turn over a full revolution. like a dead battery. lights work the batt is still at 100% or close to. ill wait a little while 20 minutes or so and do the same thing all over again. im going out to test the hell out of wires today so ill come back and fill you in a bit more.

 

ok i know of one pproblem, the red w/yellow dashes wire went dead. i put power to it and everything was fine. power came back to it on it own, idk. so i ended up driving it to the base to put fuel in it 20 miles or so turned it off and i couldnt get it started again jump it from another battery even a car. still acted like it was dead but i know there is power it turns on the lights just fine, im replacing both batterys and the alt and starter tomorrow. but i still have no idea whats going on. im betting on that red/yellow wire. thats goes from the fuse block the oil pressure switch then to the cut off relay. thats what my lay out says (i'd post it to if i could figuer out how). but in the truck there is also a "V8 Black Box" with a number that i've had run at the parts store they have no idea and neither do i never heard of it. i opened it and it says relays but i already have relays that look like relays so what gives? umm... other then that i cant think of anything else, i'll post if i remember anything.

 

oh yes i have fuel, plenty of that... all over the place. and i have spark, but i think it is a bit weak. im thinking it is the power in on the coil. cuz i just put in a new msd coil. that helped when starting to. and what a difference altogether to... lol.

 

I have that same black box; if the part number on it is D7HF-9F441-AA it's a speed
control amplifier:

https://www.ford-trucks.com/forums/6...ml#post5318839

There used to be a pic online here but it's been deleted; mine is on the firewall just above
and to the right of the gas pedal.

The red/yellow-dashes wire feeds power to the engine solenoids.

Your starter cranking slow, that's indicative of bad or corroded cables OR bad ground
connections (including starter <-> engine block as well as battery negative cable to
engine) OR a dying starter motor. My approach would be to remove all the cables and
clean 'em as well as the grounding locations on the engine/frame, replace the cables if
they look questionable. I'd do something like that rather than throwing parts at it.
Alternators & starters can be tested at the parts store but heat-caused failures can be
hard to detect in the store.

Could also be the solenoid inside has deteriorated to the point that it will only
SOMETIMES be able to send full power to the starter, it will depend on the orientation of
a quarter-sized copper plate that crosses the two thick cables together.

Do you have a volt meter and can you measure the voltage at the battery?

You say the headlights come on but the starter has problems cranking... see if the
headlights dim when trying to crank the starter, do they dim significantly or no? If they
do, this means the starter is drawing a lot of current, further justifying paying attention to
the wiring & connections I mentioned above.

You have the 460... when you are cranking the starter, power is sent directly from the
starter solenoid on the fender to the fuel pump. After it starts, power is sent to the fuel
pump relay through an oil pressure switch on the engine (this relay burns out eventually):




Thanks for the detailed explanations, they help.

Hope the above helps ya, let us know how it goes, OK?

Look here for picture-posting help:
User Gallery & Picture Display Help - Ford Truck Enthusiasts Forums

 

lmao... that wiring diagram is the one that helped me find the first time this happend. i just find it funny... ill try those tomorrow, i was thinking of those wires as well, but i wanted to replace the starter cuz of heat problems basically when it's hot it dont run. i've heard of it before, my buddy had to leave his car running for and hour and a half while he was in walmart cuz of the same problem... stupid but funny... i still think there is something else that drawing alot of power or shorting it out because the store will charge them and theres times that i do as well and they just seem to die, but with the above heat problem it might not be the batts... humm... guess ill find out tomorrow when i wires and starter. thanks alot bud.

 

Quote:

Originally Posted by BeastF-250

...i wanted to replace the starter cuz of heat problems basically when it's hot it dont run.

I've heard of this phenomenon but haven't experienced it myself.

Quote:

Originally Posted by BeastF-250

...i still think there is something else that
drawing alot of power or shorting it out because the store will charge them
and theres times that i do as well and they just seem to die

I guess I forgot to think about or mention above, but I guess there is still a
possible battery problem. You can get a volt meter from Harbor Freight for
a couple bucks if you don't have one already, they're helpful sometimes.

 

well the starter was the problem. i would have said something earlier but i just got net again moved twice in five days out and back things didnt go right. but im back and thanks for your help, as i said the starter was the problem i'm thinking i will have to replace the alt here soon as this one seems to be going the battery is holding frim there wasnt any problems there ive checked them and had them check by pros so yea. but yea the starter one of those things you'll think wont happen to you, till it does and you forget that it was a problem for someone else. lol thanks again bud and ttyl. oh one other thing im looking for some 285's to 315's on r16's anybody knows or got some for cheap let me know need them badly.