Fuel filter change gone bad

[Spidermonkeywrench]

:confused2:I have been fixing up a 1975 Ford 7500 Backhoe for a friend and decided to change the filters all the way around. Oil, Hydrolic, Powersteering... I got to the Fuel filter today . Swapped out fine. I primed it and bled off the lines and now It wont start. I am no deisel mechanic by any means. I know my way around em and what to look for but this has me stumped. I heard people say crack the fuel line nut and crank it. Ive also heard em say to just pump it from the lift pump primer. If anyone knows of anything I mighta missed I could sure use some help.

 

[mahlers]

Did you crack the fuel lines at the injectors and bleed them off from there when you were priming? I'm not sure about the 7500, but most of the tractors I've messed with have a low pressure and a high pressure pump. The low pressure pump generally has a primer lever on it, and you've got to make sure that you get the high pressure pump fully primed - and the way I've always done it is to crack one of the inlets to the injectors and keep priming until fuel flows out. The most important thing there is that you have fuel in the high pressure pump when you start cranking it over - running that dry can hurt it fairly quick.

If it's not the fuel, I can't think of anything else that might be causing the problem.

 

[Jerry/MT]

Here's a general method for bleeding a diesel fuel system. before you start, make sur ethat you have good fuel flow from the tank to the filter. the strainer on the tank valve can clog and no ammount of bleeding will fix that.

Bleeding a Diesel Fuel System
Start at the fuel outlet of the tank (inlet to the filter). Shut the tank valve, remove the line at the filter inlet and holding a suitable container to catch the diesel fuel, open the valve. You should have a CONTINUOUS rush/flow of fuel out of the line. If it dribbles or is intermittent, check the fuel cap for a blockage of the fuel vent or the strainer upstream of the valve for clogging. The strainer/screen is attached to the shut-off valve, and is positioned up inside the tank. You will have to drain the tank and pull the valve to clean the screen.
If you have good fuel flow at that point, reconnect the line and open the bleeder screw at the top of the filter. Turn on the tank valve and wait till you have a steady flow of fuel with no bubbles at the top of the filter, then close the bleeder screw.
Your pump may have a bleeder screw. If so, open that until fuel streams out with no bubbles, then close it. If you cannot identify the bleeder screw, loosen the inlet connection at the pump and purge air at that point.
Go back and make sure ALL the fittings in the fuel delivery system are tight so they cannot suck air.
Make sure the battery is fully charged. Loosen the fuel fittings at the injectors, either one at a time or all at once. Crank the engine till you see all fuel at the injector fittings and then tighten the fittings. If you do indvidual fittings, the engine will usually start before you get to the last fitting.
Alternatively, you can "tow-start" it to save wear and tear on your starter. Leave the injector lines cracked open at the injectors at first to purge the lines. Then tighten them up and she should start.
Your injection pump puts out a very small amount of fuel (high pressure/low volume). BE PATIENT. If the lines are totally empty, it takes a lot of cranking to fill them up.
sixbales & Jerry/MT

 

[DieselMonk]

open the injector pump bleeder screw

 

[Soundguy]

check the old gasket ring.. intact? or missing a chunk?

 

[Spidermonkeywrench]

OMG! I forgot to open the bleeder screw at the front of the pump. Tons of preasure in the filter too. Took a bath and changed. Bled it at the pump and it cranked right up. Thanks guys. World class knowledge on this forum.

 

[Spidermonkeywrench]

Awesome! Got her done. Perfect diagnosis Sir.