Turbo Hot

1995 F350 7.3L Turbo. Will not start when hot or cold?

This truck will not start when hot or cold. This truck has about 300,000 miles. This all started on a cold morning when I did not have it plugged in. I knew I some bad glow plugs,but it still usually starts. It started turning over and trying to bust off but would nver start all the way, and then it just quit trying to bust off. I replaced the mechanical fuel pump located between the heads. My batteries are hot so I know that I am getting fast enough rotation. I have also checked all fuses. I'm thinking it might be the fuel injector pump. I'm reluctant to pay that much untill I'm postive that it is the problem. How can I tell if the fuel injector pump has gone out?

First off I would never put ether to an engine that has a intake heater or glow plugs. As I was reading your message I was thinking fuel pump as a first possibility, and saw you did that. That engine does not have an injection pump, it takes high pressure oil to make it run. If your high pressure oil pump isnt putting out at least 500psi it will not start. Your injection pressure sensor could be bad an cause the same problem, if you hook it up to a computer you can tell what the sensor is reading if it is. To tell if your pump is dead you need to dead-head it. You need a gauge that will go to 5000PSI, an hook it into the lines where they go from the pump into the heads, block one and hook the gauge to the other. It should if the pump is good go to about 4000PSI. If it does you have an internal leak possiably an injector.
Also could be an injector o-ring they were bad on that year. If it starts up with a radical idle they need new ones.