97 Monaco Dynasty Fuel Issue

[wolfman73]

Hi Group,
New to the RV world and I recently picked up a 97 Monaco 32' RV. Has a Cummins (not sure on the model though) with 19k miles. Its having a fuel issue and I am thinking its the fuel transfer pump/lift pump but wanted some opinions. If I pour fuel in the water separator or clear filter just before the main fuel filter it starts right up and runs til the fuel runs out. After doing this a while and using the primer bulb I was able to get fuel to continue to flow for a little while and was able to drive it to the gas station and fill it up. However, when I went to start it back up the issue re-surfaced. I spoke to my local Cummins service rep and he is thinking a transfer pump as well. Anyone have any experience in replacing these or is it better to let the service dept do it? Also, anyone have any info on the engine?

[jacwjames]

Really need to know the engine model to confirm.
But, I have a ISC 8.3 Cummins. It may be similar to yours.
The fuel transfer pump is mounted on the passenger side of the engine above the starter towards the rear of the engine(which is toward the transmission).

You should be able to hear the fuel pump start when you turn your key on, it will run for about 30 seconds to push fuel to the injector pump.

The transfer pump has 3 bolts that hold it together, these bolts have been known to loosen up, which lets the pump suck air and leak fuel. First thing I'd do is try tightening up these bolts.
Next check the fuel filter. Note that some fuel filters come with a small gasket that fits up over the threaded portion, make sure someone hasn't left an extra one on.

Change both fuel filters, perfill the filters with clean fuel, best to plug the center hole and pour fuel in the outside holes.

Try turning off and on the ignition 3-4 times to get air out of the system, then try to start.



You can join the Cummins Quickserve site, setting up the account is free. Once you have an account you can put in the SN of your engine and then can look at what resources are available, you can look up maintenance information, parts etc.



My fuel transfer pump number is 4935005, you can do a search and see what it looks like. Cost is ~$300

[153stars]

The gaskets for the transfer pump have discontinued OEM but have been reproduced by a couple small parts guys for around 10 bucks.

[Skip426]

Welcome to iRV2.

Sorry your first post is about problems .

Unfortunately your coaches year and the changes the Cummins went through in the 97/98 production years lead to many information issues.
You have to know if your engine has a fully mechanical injection pump; 12 valve engine; or is one of the very first ISC 8.3 L engines with the CAPS ( Cummins Accumulator Pump System ).
If you've been working on the engine can you identify the type of fuel injection pump from these two pictures .
First is the mechanical P 7100
Second is the semi electronic CAPS used on the first ISC.
Different issues for both fuel systems can give the problem you describe.

[veraken]

Get your ESN (engine serial number) and go to

https://quickserve.cummins.com/info/index.html

Register your vehicle. It's a great source for info on replacement parts. You can also call Cummins Customer Service ( 1-800-343-7357 ) and give them your ESN

This will tell you where to find your ESN :

https://www.dieselpartsdirect.com/fi...-serial-number

[Ivylog]

On a 97, I doubt you have a lift pump which you can hear run on the engine for about 30 seconds when you turn the key on.
The grey electric solenoid in the first picture ^^^^ is a common problem... does not pull the fuel shutoff all the way open. You can manually help it.

[RKins]

Hmmm, I can hear something purring for about 30 seconds. When I turn the key the engine starts right up, no delay.

[Skip426]

Originally Posted by RKins

Hmmm, I can hear something purring for about 30 seconds. When I turn the key the engine starts right up, no delay.

If your in the drivers seat and hear purring , at key on, there's a good chance that what you can hear is the dash HVAC unit's vacuum pump.

OR; I suppose there is a chance that a PO , added and electric lift pump near the fuel tank to help get the fuel back to the engine's mechanical lift pump.

Look on the outside of the fire wall for the electric vacuum pump pictured below , disconnect it and see if you still hear the purring at key on.

[Gary RVRoamer]

Wolfman73's '97 Dynasty almost surely has a mechanical lift pump rather than electric, but that's the first thing to verify (see others replies on how to do that). The info I have says the Cummins 5.9L "B" and 8.3L "C" engines use the same lift pump. A Dynasty might have the "L" engine, though, and that is a different fuel system.


I'd be looking at the possibility of a collapsed fuel line from lift pump to tank or a clogged intake on the lift pump (it has an intake screen). There is also the possibility of a leaky pump gasket or simply loose mounting bolts. Work all of those possibilities before deciding the pump itself is bad.

[cry42]

My 1997 Dynasty is a Cummins C8.3 mechanical engine. Has a mechanical fuel transfer pump bolted on the passenger side of the engine block, just below the Secondary Fuel Filter. Fairly easy to change out. Also may wish to insure Fuel Cut Off Solenoid is staying open.

[u8at711]

on my 97 signature, the fuel shut off valve failed last fall, would run for a few seconds the motor would quit.