Cat 259B3 fuel issue when hot

[Frank Nesbitt]

I recently acquired a early (YYZ05843) CAT 259B3 skid steer. When cold, the machine cranks and runs fine. Lots of power and no skipping, smoke...nothing out of the ordinary. After running just 5 minutes or so if the engine is cut off it will crank back up if tried in 10 seconds or so. Wait any longer and forget it. Acts and sounds like no fuel. I have checked the electric primer pump and verified fuel is getting to the injector pump. I have opened an injector connector and get almost nothing in the way of fuel except a spit or two. I would assume (yes I know what this means) the high pressure pump has issues. Since I have never torn into an injector pump does anyone have any suggestions? Is there something else I could check before spending $ on pump? Thanks for all relevant suggestions

 

[heymccall]

The achilles heel in that fuel system is that the primer pump and filter can have their inlet plugged.
2nd issue is the accidental omission of the Oring between filter and bowl assy.

Very common.

Here https://www.heavyequipmentforums.co...ss-of-power-moving-forward.78699/#post-832995

Here https://www.heavyequipmentforums.com/threads/cat-226-fuel-problem.78929/page-2

 

[Frank Nesbitt]

Heymccall, thanks. I have replaced all fuel lines and checked the filter head and chrck valve. I will remove the bowl tomorrow and make sure it is installed

 

[heymccall]

"Checked filter head?"

Unless you physically verified no debris between inlet elbow and the concentric tube (by removing inlet fitting, primer pump, filter element, and entire head assembly), then you haven't checked it to my satisfaction.

I only emphasize this because I don't have enough fingers and toes to count the number of times that I've been dragged out to a machine that has been checked over "thoroughly" only to find a missing bowl Oring, or debris blocking the filter inlet.

It's your machine.

Also, electric pump "prime" enable is stupid weird, and not like in the book.

So, next time...
When you think it's not getting fuel, enable the "prime pump" by leaving the seat bar up and turn the ignition to crank for a second, then leaving it in run for, say 20 seconds.
Now, retry starting it (sitting in seat with bar down).

In other words, the electric pump won't run if the key is only turned to RUN.

 

[Frank Nesbitt]

Yes, head was completly removed, fittings and filter. Taken off the machine and verifird no blockage. Like i said in first post i verified fuel to the injector pump. No air in sample taken at pump just good clean fuel. Not getting from banjo fitting at inlet to injector. I did verify fuel returning to tank from system when running the primer pump. As for the pump i did not use the switch. I wired up a hot wire to a momentary switch so i could verify what was going on when the pump was running.

Unit has sat for the last 6 hours and when tried immediately got fuel to injector 1. Tightened fuel line at injector and it fired up no skips or smoke. Ran 10 minutes and turned switch off to bleed hydraulics for attachment. Unit would not start back up.

 

[Bullseye Beaver F.]

Did you check all the filters?

 

[Frank Nesbitt]

All new fuel lines primary plastic filter and cat water seperator.

 

[heymccall]

primary plastic filter

??? I don't see that in parts manual. What part number did you use?

 

[Frank Nesbitt]

Baldwin Heavy Duty BF7863 In-Line Fuel Filter on the intake side of filter between tank and water seperator.

 

[thepumpguysc]

U don’t get fuel at banjo bolts on injectors

 

[Nige]

By "banjo bolt" do you mean the union nut in the connector for the HP fuel line on top of the fuel injector (circled) or somewhere else..?

 

[Frank Nesbitt]

My banjo connections are on the injector pump. The nut at the injector is where i get a little spit of fuel. The supply and return lines at the injector show no signs of air. ( used clear container to catch sample)

 

[thepumpguysc]

Be careful when checking anything at the return on the injector..
A> it wont tell u anything
B> some of those return lines run back to the filter head.. so if your running/diagnosing anything at the return line, your introducing AIR into the system.. thru thr filter head..

 

[Frank Nesbitt]

The return on this unit goes to the fuel tank. I'm getting some clear tubing to make sure what I think is going on is in fact what is going on.

 

[Frank Nesbitt]

Ok, finally got results. After hours of fuel line replacement, watching bubbles, changing filters, searching for someone smarter than me i have an answer. My issue with unable to do a hot start has been fixed with an injector pimp. Took mine off and had bench tested.......low pressure when hot fuel got into injecter pump. Estimate of 900 to rebuild. CAT had a sale so i got a new pimp with free shipping. All total 1300 dollars. Old CAT purrs like a kitten..... Thanks for all the informative answers on this site.