won't start

[scottstef]

hey folks,

i am stuck. 89 F-350, old uhaul truck it won't start.

before it wouldn't start this time, the truck has been difficult to start. typically the gas pedal had to be pushed in and out multiple times to get the truck started. when the engine was cold, i really had to pump the gas pedal. when it was wamrm and i turned the truck off, it would restart without issue. also, when the truck was running it ran great, idled properly when warm, ran smooth as cit could when war. the last few times i was working with the truck, i noticed a hissing sound when the truck was shut off.

now the engine will not start. engine cranks as it should. glow plugs are brand new. after the wait light goes off, i hear the relay click for about 30 seconds. new fuel filter. fuel gets to the injectors. when i manually move the accelerator, i can hear an air leak/hissing sound coming from somewhere around the injector pump.

any clues on what i should try next?

[cdnsarguy]

Got a C6 trans.......3 speed. Check the vacuum lines and the coffee can for holes on the bottom. The VRV on the IP has vacuum to it and I hope you did not break the fittings off.

This should not stop it from starting though, what brand GPs did you use. How long does the wait to start light stay on...... Check for power at the IP front drivers side connector, key on... disconnect and reconnect several times do you hear a click each time.

Have you done a pressure and flow test of the manual lift pump....

Important the fuel shutoff solenoid (FSS) wire on the IP should be disconnected you do not want a start just cranking. Re connect FSS after test complete.

Take the filter header Schrader valve core out and hook a hose and pressure guage to the outlet.........crank engine see what you get for pressure, should have 4-6 psi from a good lift pump.

Volume test same place hook a hose to it crank over the engine 10 seconds you should get 1/3 pint of fuel minimum.