CAT 480F IT backhoe no start

[bsamot69]

Our CAT 480f backhoe will not start. It cranks. The machine has been operating pretty flawlessly since I replace the transfer pump some months ago. One morning I tried to start it and the battery was dead. I removed battery and recharged it. Now, it will crank but not start. When the key is turned on the fuel pump runs and keeps running. The machine does not start. I believe the fuel pump initiates for a few seconds then turns off prior to charging battery. I have an inline clear fuel filter installed and it showed barely a trickle of flow. The tank is near full. I noticed the fuel line from tank to pump had a small tear so was pulling air. I repaired that and pulled the filters, which had fuel in them, then reinstalled them. Turned key on and filters filled up but the ful pump continues to run until key is turned off. The machine still cranks and does not start. I checked all the fuses and none were blown. I should mention that before I replaced the fuel pump months ago I had filled the filter and seperator with fuel so machine would run so I could move it to the repair area. Now, it will not start with fuel filters filled. The return line into tank has good flow. I am not sure the direction to go to diagnose problem. On this machine, does the fuel controller turn on and off the pump? Is there a sensor or other input to check? Is there a wiring diagram available so I can check the controller input/output? The power and grounds? I'm waiting on replacement fuel filters just in case it is a plugged filter. Any advice or suggestions are greatly appreciated. The serial number JWJ01898

 

[Nige]

Is there a wiring diagram available so I can check the controller input/output?

Keep an eye on your messages.

 

[Coytee]

I'm not a mechanic.... nor, did I stay in a Holiday Inn last night.

Seems to me you need two essentials.....fuel and compression. Presumably you have compression so I'd look at fuel first. On my JCB, if I have ANY breaks in the fuel line, I'm dead in the water until I break/bleed the fuel line at the injector and crank it over. Have you done that?

In my case, I simply crack/loosen one or two or three (of the four) injectors. Don't have to back them off much, just get it to loosen. Crank engine over.....are you getting fuel spurting out? If yes, tighten one a bit. In my case, I only do one/two and when I see fuel start to spit out, it usually starts to cough and will start BUT, run very rough. As I tighten them down, the rough idle smooths out and I'm good again.

Are you getting ANY puffs of smoke out the stack?

 

[Nige]

Seems to me you need two essentials.....fuel and compression.

That only applies to a mechanical engine. In the case of an electronically-controlled engine the free passage of electrons also come into the picture. Hence the first thing he needs is an electrical schematic.

 

[bsamot69]

I made a mistake on the model...it is a 420f. My bad.

 

[Nige]

I made a mistake on the model...it is a 420f. My bad.

Don't worry, the schematic I sent was based on your actual Serial Number so it will be the correct one.

 

[thepumpguysc]

I’ve seen some mdls of supply pumps that quit pumping/ticking when they reach a certain pressure and start back when that pressure drops..
Which leads me to think the overflow banjo bolt might be broken.?? The banjo bolt holds about 25 psi before it opens..
It’s just a thought..

 

[heymccall]

"I have an inline clear fuel filter installed"

Where is it installed?
Is the OEM steel inline filter still in the system?
The one circled below...


What "clear inline filter" are you using? Part number, please. If it is not a "screen", but rather cellulose, that's gonna be an issue.