CAT 96J Fuel system Issue

WarnClub · Apr 7, 2022

Hey all,

I have a Cat 96J that one day just decided it didn't want to start. I narrowed it down to an issue with fuel pouring out of a
nozzle (circled in picture) under the fuel pump injector. I took apart the injector to look at the washers and they were in rough
shape, went to replace the washers and a whole new injector was cheaper so I ended up just getting a new injector. Ended up not
fixing the issue. I had a guy from Cat out who said that it might be the seals in the ?manifold? (arrow pointed to it in pic) next to the injector. Now he was
an old timer but admitted to not having worked on a 96j since the 70s. His fix would be quite a bit of labor so I just wanted to
see if anyone had any ideas what could be causing this before I tore the whole thing out. Thank you in advance.

This post was edited by WarnClub on 04/07/2022 at 03:51 pm.

AJ. · Apr 7, 2022

Tell us exactly what happened, did you stop the machine at night say and come back to it in the morning and it would not start, or did the machine stop of it's own accord, I cannot see from your picture what type injector pump is fitted post a picture of the whole injector pump, the part you are referring to as an injector is what we would call the priming pump, where the fuel is coming from is the bleed nipple, if the machine is fitted with the scroll metering pump it is possible the rack is stuck in the stop position, that can happen when the throttle is left in the stop overnight or when there is a sediment build up in the pump, mention this to your Cat man as the rack sticking was a common problem.
AJ

WarnClub · Apr 7, 2022

We had an issue with the transmission slipping and it ended
up sitting for about 2 months during the winter. We changed
the trans filter and oil tried to fire it up and nothing. Right
after we noticed the entire fuel tank had emptied on the the
ground by the blade. This is the best picture I have but will
get you another in the morning.

wore out · Apr 7, 2022

I wonder if the brass "nipple" is in a "weep hole" in the area between the driveshaft seal that keeps fuel in the injection pump and the driveshaft seal that keeps oil in the engine?

If that's the case, the "pump side/fuel seal has failed and fuel is draining oil the "weep hole" rather than trying to find it's way into the engine crankcase.

Likely, the "nipple" originally had a plastic line on it the hung down a ways.

AJ. · Apr 8, 2022

All I can suggest is you find the source of the leak, repair it, bleed the system and try for a start, I find it very confusing that you had a Cat engineer look at it and he does not know what's wrong as that engine was very common to loads of Cat equipment, from trucks to loading shovels, dozers to excavators very common.
AJ

WarnClub · Apr 8, 2022

This is exactly what we thought. We checked the seals (I called them washers in original post) and ended up replacing the whole thing since the seals were $300.

WarnClub · Apr 8, 2022

This post was edited by WarnClub on 04/08/2022 at 07:17 am.

AJ. · Apr 8, 2022

Am I to take it that now the leak has been repaired the filters clean and system bled but still no start, has there been smoke coming from the stack when the engine is cranked over, what does the discharge show on the ammeter when you are holding it on heat, the discharge should 27/28 amps or there abouts if all the glow plugs are working, if there is no smoke coming from the stack it means there is no fuel been injected, it has either air in the system or like I said before the rack in the pump is stuck in the stop position, that is a job for the mechanic.
AJ

CAT 96J Fuel system Issue

WarnClub

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AJ.

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WarnClub

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wore out

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AJ.

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WarnClub

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WarnClub

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AJ.

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