I have a 1996 F-250 with the 7.3 PSD. The truck was running great and all of the sudden was hard to crank and now won't crank. The batteries, starter, altnernator are all good. The following parts have recently been replaced: IDM, CPS, glow plugs, valve cover gaskets, fuel pump, fuel filter, oil filter, key switch.

Numerous computers have been put on with no codes being thrown. Buzz tests have been run and if the test goes through it will crank and if it will not "buzz" it will not crank. It is like it is loosing it's prime but there are no leaks, and pressures all check. Does anyone have a fuel system flow chart that maybe we can start ruling out sensors.

 

Won't turnover at all (CRANK) or cranks but won't start?
Two different things.

 

Sorry I'm just an old Florida Cracker. It will turnover but won't start. Starter spins and spins and checks out fine.

 

Do you have a "Wait To Start" light?
Local Parts store CPS are crap, need one from Ford.
What is the fuel pressure?

 

Yes the "wait to start" light comes on. It has a CPS from the Ford dealer and fuel pressure is fine. Potentially we are thinking that the PCM is bad but it runs very well when it does start.

 

It should always do the Buzz test, fuel or not.

Start here ... http://oregonfuelinjection.com/pdf/f...diagnostic.pdf

 

On long cranks, does white smoke come out of the tailpipe? If no, check the voltage off the batteries while cranking.

 

Actually, check the battery voltage while cranking either way...

 

[QUOTE=Hussler;14249727]It should always do the Buzz test, fuel or not.

That is why thinking it possibly is the PCM because communication is intermittent.

 

ICP.

Unplug it.

Drivers side on top, just off the side of the fuel bowl.

Then try and start it.

 

It won't start.

 

So sometimes it passes the buzz test and sometimes it doesn't, is that what you mean? If that's the case, when it fails, does it fail to get the test going at all, or does it buzz the injectors and then report errors with certain cylinders?

 

No when a buzz test runs there are no codes but the test will not always go run, like there is no communication.

 

I would vote PCM as well. They do weird things when they die.

 

Put a new PCM in today and it still will not start.