xFF1x

1991 f250 with the 351w and auto transmission. will crank but wont start. Im at a loss. I was pulling out of a parking lot and got about 200 feet down the road and the truck just shuts off on me like someone turned the key off.

ive replaced, starter, starter solenoid,positive battery cable, fuel filter and computer power relay. You can hear the fuel pump turn on. The battery is good.. i dont want to throw any unessecary money at, the things ive replaced were all things that were replaced in the last 10,000 miles.

Modular man

Is the check engine light on and if so u pull the codes. That's were u need to start

Chris_1

iTrader: (1)

If it will crank (turn over) but not fire, the battery, starter and solenoid have nothing to do with it.
1st thing you have to do is check for spark. Take one of the spark plug wires off the plug, stick a spark plug in it and use a booster cable to ground the plug. Now crank it over and see if you get a spark. If not start going through the ignition system electrical.
Test light - with the key on, do you have power to the coil (wire closest to the driver's fender) ?
If you do have a spark, you'll probably be looking at the fuel system. A 3 second burst of starting fluid into the throttle body, then crank it over. If it starts for a second that way but won't start on it's own, you have a fuel issue. Fuel pressure gauge, test the TPS.
There's your starting point anyway.

fltdriver

Follow chris 1's advice and you should at least be able to narrow it down to a specific system (fuel, ignition).

Any starting issues when the engine turns over should be addressed by:
Pulling codes (always pull your codes FIRST-and the CEL doesn't have to be on to have codes)
Checking for spark
Checking Fuel Pressure

I would be willing to bet that you had something come off/give out preventing power from reaching the spark plugs.

xFF1x

Chris1 what is this coil? Do you by chance have a picture of it? And should i just use the booster cables for ground to test it too?

nrivera04

Follow your center plug wire coming off the distributor cap... Black or grey little box about the size of a fist.

Chris_1

iTrader: (1)

You need to use a test light to see if there is power to the feed side of the coil wiring.

xFF1x

I have no power at the ignition coil.. what would be next and how do i test it? And guys, i forgot looking at my negative cable, only looked at positive, but the negative was split and open at the frame, could that be the issue? Thank you guys for the replies so far. Im by no means a mechanic, just a kid with tools trying to save money

fltdriver

Yes, you must have proper ground for electricity to flow. No ground, no start. Fix you terminal/ground wire, clean up any chassis grounds in the engine bay, retest coil while turning it over. If still no power chase it back until you find power.

xFF1x

Hey guys, thanks for helping me out so far. It was my ignition module. So i got a new question, my truck now stalls out randomly then will start fine once i get to a stop. Could this be that i had my distributor out to change the mmodule. Help at all?