Thursday, February 22, 2007

Cummins ISC Diesel Engine-Installing Complete Fuel Transfer Pump on a Thomas School Bus

Cummins ISC Electronic Diesel Engines installed in a Thomas School Bus have a few accessibility problems.

Replacing the fuel transfer pump is one component that requires some removal of surrounding parts behind the transversely mounted radiator and charge air cooler.
This photo shows the transmission cooling line, power steering hose and radiator support brace removed.

The fuel transfer pump is mounted at the left rear of the engine block above the starter.

There are five fuel connections at the fuel transfer pump manifold and the wiring bulkhead supplying the engine ECU [electronic control unit]

As noted in the previous post the pump and motor assembly cannot be inter-changed with the old housing.
Here you can see the difference and why leakage is guaranteed since the new rubber formed gasket will not seal properly.
This the only difference from the change-up on design, obviously an improvement from previous problems with leakage.
The larger orifice on the original housing is the output side.

The transmission cooling hose and power steering hose to the fan motor have been re-installed including the radiator to frame support brace.
Removal was required to gain access over top the frame.

This is the best and the quickest way to replace the fuel transfer pump on a Cummins ISC Diesel Engine on a Thomas Pusher School Bus.

School Bus Mechanic on my "Squidoo" Lens


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Hmmm... this is the first time I read about "Cummins ISC Diesel Engine-Installing Complete Fuel Transfer Pump on a Thomas School Bus". so interesting! Thanks for sharing this post. I enjoyed reading it. Keep posting!


Scott Gounaud said...

My late father told me once that there really isn't anything new under the sun - meaning if you have an issue with something, someone else has probably had it too.

Some great info on the Cummins ISC fuel system, which I am currently VERY interested in as my 2007 Monaco Knight will not start after primary fuel filter replacement.

Is there a procedure to re-prime the fuel system? I've tried suction and pressure on the lines to no avail. The 'lift' or transfer pump seems to be working for 30 seconds each time you turn the ignition on, but after multiple tries the %$#^& engine still will not start...

John Whelan said...

The primary fuel filter (between the tank and the transfer pump)must be primed before installation. If you've done this then the transfer pump may be weak & there is still air in the system. Pressurizing the fuel tank helps as well with a shop towel wrapped around an air nozzle into the filler tube. Not too much pressure...

The secondary fuel filter does not need priming since the pump will fill it up easily. It may take 2 cycles to get the engine going.