Help my 7.3 Power Stroke cranks but will not start.  So lets put down that can of starting fluid and figure out why it won't start instead of causing more damage.  The first step in a 7.3 no start is to simply check the oil level.  Yes the oil level.  Your engine could be low by just 3-4 quarts causing a hard start.  Unlike other diesel engines the Powerstroke has two oil pumps.  One to lubricate the engine components and the other to operate the fuel injectors. 

    Next lets sit in the driver's seat.  Turn the key on, does the "Wait to start light" come on?  If the light does not light up check the 30 amp fuse under the steering wheel.  This fuse will operate the fuel bowl heater and a power circut for the powertain control module.  A common 7.3 PSD problem is the fuel bowl heater shorting out under the fuel filter, which in turn blows the fuse. 

   Try and crank the engine.  If you have a tach guage does it move?  If the computer does not see a tach signal it will not turn on the fuel.  The truck must also crank fast enough.  If it is not cranking fast enough it won't generate a signal for the camshaft position sensor.

  Next step is checking glow plugs.  Generation one and two powerstrokes will vary in their glow plug control, but I will keep this simple.  On most PSD on the passenger side on the engine on top there will be a relay.  This relay has four terminals.  (note sometimes there are two relays next to eachother one is for glow plugs and one is for the intake heater.  Also on some models the glow plug relay will look like a mini control module.  do not go poking around on these wires it requires a different set of tests.)  Most PSD's have the 4 post relay.  One wire will have B+ all the time, across from it on the other big post this is the feed to the glow plugs.  The Two other terminals smaller in size, One is key on power from the ignition switch and the other is a ground controlled by the Powertain Control Module.  Verify That the relay is working.  Even if it makes a click noise, verify the relay has really switched power.  Now the glow plugs will need to pull about 180-190 amps when cold.  This is total for all eight glow plugs.  Yes that is alot of amps so be sure your battery and charging system is up to par.  When your truck losses one glow plug it will become harder and harder to start.  It is only a matter of time till all the glow plugs fail.  Can't see the glow plugs.  That's because they are located under the valve covers.  AAAhhh do not use starting fluid on a hard start.  If you have only 3 glow plugs working and you use starting fluid on it you are going to cause engine damage very quickly. 

  These are just a few 7.3 Power Stroke problems issues to keep in mind on a crank no start.