Caterpillar 907H fuel priming strategy

[XSKIER]

S/N SJM1
I changed the filter, but did not receive automatic priming via the electric fuel filter mounted pump. Assy 232-5877 I've found this system to work ok on other equipment equipment of the era, and seems like there is a 10 second timer in the ignition on position for this purpose. I've checked the fuse, swapped the A/C relay with the fuel relay, and ensured that the pump works by direct wire. What I can't figure out is how the timed cycle gets to the relay. Although it could be entirely possible that a wire is broken from the relay to the pump, as I have had some broken wires on this unit before. If there is a wiring schematic out there, I could sure use it on this one.

 

[XSKIER]

Additionally, is there any harm to running the machine without the priming pump functional at each key on? Always fires right away and has full power. Another peculiar strategy on this unit is a 10 second dwell on the work tool coupler pins. I'm thinking that the relay for the coupler and the fuel pump could be crossed?

 

[heymccall]

On my 248b, to prime a new fuel filter, the machine needs a failed, brief, crank attempt.

Change filter(s), turn key on, bump the key switch to crank briefly, then leave in run. The fuel pump priming sequence then begins.
Normal starting doesn't require this procedure. From the moment the ignition switch engages "crank", the electric primer pump comes on.

 

[Nige]

If there is a wiring schematic out there, I could sure use it on this one.

Serial Number above or below 208.? There are two different schematics.

 

[XSKIER]

Serial Number above or below 208.? There are two different schematics.

462

 

[Nige]

Sent you a PM.

 

[XSKIER]

On my 248b, to prime a new fuel filter, the machine needs a failed, brief, crank attempt.

Change filter(s), turn key on, bump the key switch to crank briefly, then leave in run. The fuel pump priming sequence then begins.
Normal starting doesn't require this procedure. From the moment the ignition switch engages "crank", the electric primer pump comes on.

This "failed attempt" strategy is the way the 907H works too. I have a 279C2 that the priming pump works at key on. Most other tier3 equipment I have owned has had key on fuel priming. My mistake on the 907.