cummins fuel filters change out

Good idea to have a warm engine first for easier starting. Maybe not hot depending upon where your filters are located.

BTW Neither my ISC or ISL stumble when the filters are changed and the pump is used to purge the filter air. Apparently the lift pump takes care of the air and the fuel in the pump/injectors is not affected.

My 330 ISC lift pump would run for 30 seconds after the key was on. Change both filters, 4-5 cycles with the key and it will start right up.

But then Monaco moved the filters on my 04 Endeavor to a locker so it took about 15 cycles.

BTW Key on, head towards the engine and you'll hear the pump running and then shut off.

I also like to warm up the engine a little before starting fuel filter change. Not enough to get it hot, just enough to get the cylinders warmed up some, so it starts easier

As soon as the engine starts, take it to at least 1/2 speed. Rev it up, so if it stumbles a little, a better chance of keeping going. Another reason to have it warmed up a little, so not revving on a cold engine.

I can only give you information based on my 07 ISB in an 08 HR. First determine if your secondary/chassis filter has a priming pump on it. If it does replace the filter, cycle the key a few times and then pump the primer knob until you feel the system pressure build up. Fire the RV up and set the fast idle, see owner's manual. Let the vehicle run for a bit. At one point you will feel it stumble as any air in the system passes through the injectors. When the engine smooths out disengage the fast idle and shut the engine off. Remove your engine cover in the bedroom, locate the primary fuel filter which is on the engine and replace the filter. Cycle the key a few times then head back down to the secondary filter and pump the primer until you feel the pressure build up in the system. Repeat the start up procedure used for the secondary filter.
If you replace both filters simultaneously you will have start up issues.
Randy

See page 213

07 Ambassador Owners Manual