Hello All
On Sunday I noticed the fuel pressure drop and before the engine stopped I shut it down. Assuming it was low fuel I refilled the diesel tank and primed the system. I restarted the engine but now I cannot get the transfer pump to pump fuel.
I can keep the engine running and the fuel pressure up with the hand pump but as soon as I stop the fuel pressure drops. I took the top off the fuel filter housing and watched the supply from the transfer pump while I turned it over and there was no movement.
Looking at the parts book there is a check valve after the transfer pump in the fuel filter housing but I can't see that being the cause
I am thinking the next step is to pull the cover off the transfer pump and turn the engine over to make sure the gears are turning. I did not check to see if it actually ran out of diesel I just added more so maybe the reason the fuel pressure dropped was an issue with the transfer pump.
Before I dig deeper is there anything else I should check.

Regards

Phil

Does your 944 have the small screen in a bowl at the transfer pump? If so remove and check it, and replace the bowl gasket. Start at the tank first. Is the fuel cap venting? Then begin by checking the lines for fuel flow to the transfer pump. In the transfer pump there is a small keyway in the shaft, I have seen those sheared off. Also could be the pump seals failing. However, again, make sure you got flow from the tank.

don't know if the transfer pumps are similar but on my D3B (3204) there is a filter screen inside the inlet fitting that gets clogged and inside the transfer pump are 3 little plastic check valves that can fail---check your parts book

Hi Team,
my 43A 944 grey OMI (Form No FE33619 - 8 ) tells us that "the primary fuel filter is mounted on the left hand side frame directly in front of the radiator"
As described above it should be directly below the fuel transfer pump and injection pump which are on the engine.
Loosen the large bolt head on top of the unit and remove the can which contains a fine mesh screen to filter out large debris.
Wash the element with cleaning fluid and refit using a new rubber gasket (should be a 8H2778) in the groove under the top of the unit--maybe cooked a bit hard and difficult to remove in-situ--remove the top cap and work on it on the bench if needed.
Bleed the system again after refitting.
Cheers,
Eddie B.

Hello All
Thanks for the replies. The filter is located as Eddie said but it is new and is before the tee that supplies both the hand primer and the transfer pump.

Today I took the cover off the transfer pump and made sure the gears turned when I turned the engine over. There was no fuel in the pump. I checked all galleries were clear and squirted some oil in there with an oil can and reassembled the pump. Used the hand pump to get fuel back up to the main filter and tuned the engine over again. The pump appeared to be pumping so I put the top back on the filter and started the engine. Fuel pressure went back to the normal range and the engine ran fine.
I don't know if it had an airlock or the pump has a little too much clearance (hence the reason I added oil) but either way it is working now and hopefully it stays that way:)

I priced a new pump from Cat and it is $3172.57 Australian dollars. A lot of money for a little gear pump.

Regards

Phil

The transfer pump is a pricey item. You should be able to get a 24v electric transfer pump and install it in-line to help the original transfer pump. Over the years I have done this for several machine owners. I just wired a switch to it, so that the electric pump can be switched on a few seconds before cranking the engine. Just a suggestion !

I'm taking a guess at part number but I believe your looking for a 9M4953 pump.
Runs about $400 to $500 for an aftermarket version.

Hi Team,
my 43A1-up Parts Book (PB) shows a 8H9794 Transf. Pump, and my 43A3012-up PB shows a 9M4943 Transf. Pump.
Both use same internal gears, main bodies at least have different P/No's and the 9M4953 has provision for a service meter on the cover/end plate.
I stand to be corrected.
Cheers,
Eddie B.

Hello All
Eddie my parts book shows a 7M9090 pump for my serial number 944's original engine. It has a different mounting for the hour meter than the 9M4953. The engine now in mine is out of a 950 so it has the 9M4953 pump.
At this stage I think it was an air lock as the pump is pumping at full pressure when running and even at low idle the pressure stays in the green zone.

Regards

Phil