I have a 1989 ford f250 7.3 IDI diesel that will crank but not start. Not sure what the problem is and am newer to diesels so don’t know if it is just cranking too slow to start. Any information is appreciated. Thanks

 

That's not much info to work with, but here is a most basic instruction.

Check that your battery is charged, working in good condition, check battery terminals for good contact, check for loosness at the starter, if the motor is not cranking fast.

If it is cranking fast, un wire the trigger or main power to the glow plug relay.

Crank 5 seconds, and use a screwdriver or the like, and press the valve in the middle of the shradder valve, on the fuel filter base assembly.

It should squirt fuel, if it squirts air, then you have an air intrusion, and will need to get the air out of the fuel circuit. That might range, from crank - squirt, crank - squirt a few times ata minimum, or if there is big air, you will need to crack each injector line loose, and crank until they are wet, pausing to cool the starter in about 4 cycles.

If you have neither a squirt of fuel or neither s squirt of air, then you have no pressure on the incoming fuel supply, indicating a broken fuel lift pump.

If it cranks fast, you have a steady squirt of fuel coming out, and the glow plugs are disconnected, spray ether starting fluid, and the engine will start.

Note of caution. You can use one 1 or the other 1, glow plugs, or ether.

not both,

both at the same time will pre detonate and wreck your motor.

but ether is good to use if you delete or disconnect the glow plug system.

It May take extra crank or heat if it is cold where you are, they don't loke being cold, for starting, they will, but they don't like it, plug in block heater if available to boost startability.

If nothing was wrong when last you drove it, and it just needs starting with a little trouble, that's a place to start.

 

If while cranking you are getting white smoke out of the tail pipe, which is unburnt fuel, then you would likely have an issue in the glow plug system. If you get nothing out of the tail pipe then perhaps a fuel delivery issue. And yes, you do need two good batteries that will hold at least 12.6 volts in order to power the starter properly and spin the engine fast enough. Clean the heck out of your cables and terminals, and check for corrosion or broken/failing wires where the insulation has been stripped or worn away.

 

up in the stickies there are two videos in the thread how to tell a good starter from a bad one
very easy to hear the difference. a weak or bad starter will not spin the engine over fast enough for it to fire off.