Cat 1986 426 Backhoe Loader Won't start , again

[Rocket Man]

Hello all. Been sometime since my last post. This time my 426 will not start. History is the injector pump went out couple of years ago and replaced it and all kinds of fuel problems that i finally straightened out. This is the Cat 426 model and sn is 7BC00580. I managed to clear up all the problems and the machine has been doing good until yesterday when i was spreading gravel on my driveway, which is now blocked with 2 piles of material plus the 14 000 pound machine. It actuall died all of a sudden and would not start. It is getting fuel to the pump as i have an electric pump low volumn on it. I cracked the injector lines and nothing come out. The return line has only a drop or two coming out. The electric solenoid is disabled so i have to shut the engine off using the manual toggle each time. SO when trying to start the engine it acts just like it does when i forget to return the manual toggle to the run position. So question is, did something go wrong under that top cover of that pump? Could the arm for that toggle be stuck? I have never torn one down so don't know what there. Maybe somebody has had this problem before?

 

[thepumpguysc]

What kinda pump is it..
Get mdl off tag on side of pump.

 

[Rocket Man]

It is a Lucas Cav 54W 3343F742

 

[thepumpguysc]

There is a filter in the inlet side of the pump..under the big nut 15/16..
Remove the nut, the copper gasket, and the large spring..
Be careful when you remove the spring, parts WILL stick to the bottom of it..
Next, hold down the rest of the guts in the end plate with a screwdriver.. & with a 90* pick/scribe fish the plastic filter out from the side of the hole..
BE SURE TO HOLD DOWN THE GUTS..
Blow off the filter and reinstall.
Let me know if it was dirty or not.

 

[Rocket Man]

Ok! sounds good to me. I never thought of that. Yes it does get fuel to the pump but nothing seems to be coming out. So that just may be the problem. Thanks so much.

 

[Rocket Man]

BTW, what happens if i do accidently let the guts out? Can i put them back or?

 

[Rocket Man]

There is a filter in the inlet side of the pump..under the big nut 15/16..
Remove the nut, the copper gasket, and the large spring..
Be careful when you remove the spring, parts WILL stick to the bottom of it..
Next, hold down the rest of the guts in the end plate with a screwdriver.. & with a 90* pick/scribe fish the plastic filter out from the side of the hole..
BE SURE TO HOLD DOWN THE GUTS..
Blow off the filter and reinstall.
Let me know if it was dirty or not.

Ok did all that and the filter was clean. The spring and that little plunger thing was dirty and i cleaned it best i could but looks like they had rust on them. Results: still wont start and still no fuel from return line. Tested it at tank and the pump. Has good flow to inlet of the pump too.

 

[thepumpguysc]

Did u change the main engine fuel filter.??

 

[Rocket Man]

Did u change the main engine fuel filter.??

been working on it and still no start. And yes all filters are clean and when i loosen the inlet line by that big nut, there is a good stream of fuel out. squirts out.

 

[Rocket Man]

Did u change the main engine fuel filter.??

is it possible that the manual shutoff linkage inside that top cap has broken? came loose? cause when trying start it the engine sputters and trys to start just like it does when i forget to return that toggle back to run mode?

 

[thepumpguysc]

Have u bled the air at the bleeder by the name plate.??
Have u loosened ALL the lines AT THE INJECTORS.??
Is the nut tight on the shut off lever AND throttle..??
Don’t snap it off..

 

[Rocket Man]

Have u bled the air at the bleeder by the name plate.??
Have u loosened ALL the lines AT THE INJECTORS.??
Is the nut tight on the shut off lever AND throttle..??
Don’t snap it off..

yes,there are 2 bleeder screws on the pump. The lower one runs freely and has plenty of volume. The top one has no fuel coming out of it, maybe a drop or two. There must a passageway that is plugged within the pump.

 

[thepumpguysc]

One last test..
Remove the inlet fitting if it’s a 90*..
Fill the inlet hole with fuel to the top..
Crank the engine over a couple revolutions.. now go look at the fuel in the inlet hole..
Is it still there or did it get sucked down..??
If it’s still there,‘u have problems..

 

[Rocket Man]

One last test..
Remove the inlet fitting if it’s a 90*..
Fill the inlet hole with fuel to the top..
Crank the engine over a couple revolutions.. now go look at the fuel in the inlet hole..
Is it still there or did it get sucked down..??
If it’s still there,‘u have problems..

I already know it will not suck that fuel in. So what kind of problems is there?

 

[thepumpguysc]

The insides aren’t turning..
(Seized)

 

[Rocket Man]

The insides aren’t turning..
(Seized)

doesn't sound very good. does that mean the shaft is twisted in two , its not rebuildable?

 

[thepumpguysc]

To b absolutely sure, u can take the 4-5/16 screws out of the “end plate”, remove it and bump the engine to see if the center turns..
All it takes is a “bump” to tell.

 

[Rocket Man]

To b absolutely sure, u can take the 4-5/16 screws out of the “end plate”, remove it and bump the engine to see if the center turns..
All it takes is a “bump” to tell.

Ok will try that tomorrow as it is dark here now. Is that plate on the back of the pump? and are there any parts that will fall out i need to look for?

 

[Rocket Man]

To b absolutely sure, u can take the 4-5/16 screws out of the “end plate”, remove it and bump the engine to see if the center turns..
All it takes is a “bump” to tell.

also, what is next step if it turns? or if it does not turn.

 

[thepumpguysc]

Either way u have to pull it off..

If u just BUMP THE STARTER, nothing will jump out atcha.
U just wanna see if the pump will turn..