Community Forums

Mblake1 · 08-19-2019, 04:29 PM

I have a 2002 Monaco Windsor that will intermittently not start due to power not getting to the lift pump. This has caused an issue several times and the coach is currently stuck in Wyoming at a Cummings repair shop. Incidentally the coach has been at Cummings for over a week and I'm trying to get back to Georgia sooner than later.

During my last trip to Cummings they could not recreate the issue and said the pump checked out and updated some type of software on the computer.

Does anyone know if there is a relay that could possibly be sticking? If so, could you please identify the relay?

Thank you in advance for any help!

Matt

Smitty77 · 08-19-2019, 10:23 PM

First, welcome to IRV2 - and great era for Monaco Windsor'sL)!

Second. Clean all of the electronic connections to the Lift Pump. Have someone else turn on the key, and make sure you hear if it's kicking on.

I'll assume that a Cummins shop will know that 2002 CAPS era Lift Pump fed ISC's and ISL's - had known problems gasket leaks from the shift to ULSD(?). So normal diagnostics should look for any signs of leakage, and or excess air getting in via the short period of time the Lift Pump is running.

No real rocket science on Lift Pumps. Key goes on, juice flows to the Lift Pump to say run and lift the fuel to the CAPS - and boom X's 6 Cylinders as the engine fires up. The Lift Pump's time is complete on the lifting of fuel at start up - and power shuts off, and it goes dormant. The CAPS takes over and 'sucks/vacuums' the fuel it needs to send on down to the cylinders.

It's either on, or off, or failing when on due to air leakage, or intermittent electric juice.

Best of luck to you, and please comeback and share the final outcome, as it could help someone else in the future.

Travel safe, have fun,
Smitty

TR4 · 08-20-2019, 07:07 PM

Looking at a wiring schematic for my coach, the lift pump gets power directly from the ECM. I would think you would get a CEL if power was not detected. Since it’s at Cummins, they’ll probably just replace the lift pump. Could be a bad ECM, but not likely. Let us know what they find and welcome to irv2.

Bill

hypoxia · 08-21-2019, 06:04 AM

Not uncommon for the pump motor to be intermittent, it is just a 12 volt motor with brushes.

ladagobago · 08-22-2019, 06:03 AM

I would be looking at the ecm connections and also there should be a fuse in line that might be intermittent. I have seen fuses look good and test good but still be defective.

Mblake1 · 08-27-2019, 05:26 PM

Thank you all for your input! In the end the Cummings mechanic found the issue, which was a lose wire. The wire that was lose is shown in the picture I'm trying to attach. It was located in the box on the side that houses the on off switches for the batteries.