Lift pump on 8.3

[gerdutch]

Has anyone removed the screen in the lift pump while operating and relied on the filter/?

[wolfe10]

Are you suggesting that the screen is clogging up? Micron rating of HUGE.


It is there to catch the "rocks", not 5-30 micron contaminants.


Can't imagine removing it.

[dons2346]

I have torn apart a lift pump with about 60K miles and the screen was perfectly clean

[gerdutch]

Yes, the screen got clogged after 155000 mi range. Had Algea in fuel. After having fuel polished took lift pump apart and cleaned the screen.
Consulted with RV friends who eliminated the Algea with additives and changing filter several times until residue apparently was filtered out. But they had Cat Engines.
Thought was if the crud could reach the filter, for changes, is a lot more convenient that overhauling the lift pump. On a 2002 model cummins, the cost of a Fass System seems excessive, so i was soliciting thoughts on my theory?
Thinking i cant be the first thinking of it. I have not found any comments from owners of Cummins Engines with the two filter setup, before and after the pump. Suggesting they may not have the same issues.?

[jacwjames]

My Moncao with Cummins engine had the primary fuel filter before the lift pump, fuel was pulled through the primary and then sent through the secondary filter before the CAPS pump.



Have you traced your fuel lines to confirm the routing of the fuel.

[Alpine36]

“ On a 2002 model cummins, the cost of a Fass System seems excessive, so i was soliciting thoughts on my theory?”

My thoughts? Not nearly as cost excessive as a new CAPS pump installation. Fuel starvation and cavitation is the number one killer of them.

[gerdutch]

Originally Posted by jacwjames

My Moncao with Cummins engine had the primary fuel filter before the lift pump, fuel was pulled through the primary and then sent through the secondary filter before the CAPS pump.



Have you traced your fuel lines to confirm the routing of the fuel.

How was your Lift pump experience so far,having before and after Filters?

[gerdutch]

Originally Posted by Alpine36

“ On a 2002 model cummins, the cost of a Fass System seems excessive, so i was soliciting thoughts on my theory?”

My thoughts? Not nearly as cost excessive as a new CAPS pump installation. Fuel starvation and cavitation is the number one killer of them.

Thanks Alpine, you are correct.
However i am wondering if WITH before and after filters, the current lift pump serves as well as the FASS , polishing the fuel? soliciting info. for my theory!

[dons2346]

It's not the filtering problem. It is the fact that the lift pump only "lifts" for less than a minute and after that all that pumps fuel from the tank is the high pressure pump. If that fails, it is roughly 6-8 grand to replace it. A FASS is cheap insurance to save the high pressure pump from fuel starvation.

[Alpine36]

Originally Posted by dons2346

It's not the filtering problem. It is the fact that the lift pump only "lifts" for less than a minute and after that all that pumps fuel from the tank is the high pressure pump. If that fails, it is roughly 6-8 grand to replace it. A FASS is cheap insurance to save the high pressure pump from fuel starvation.

Exactly 100% correct.
On our FASS system it pre filters the fuel before delivery to the OEM FS1022 filter, then on to the CAPS pump under a constant 17psi. Original lift pump has been bypassed. Nothing is filtered on the return side, with the exception of what the Titanium Series FASS pump doesn't deliver downstream to the CAPS pump.
The ISC OEM lift pump/fuel delivery system was never designed to pull fuel from 30' away. A major snafu overlooked by nearly all coach manufacturers.
The FASS upgrade is money well spent.

[Alpine36]

Originally Posted by gerdutch

Thanks Alpine, you are correct.
However i am wondering if WITH before and after filters, the current lift pump serves as well as the FASS , polishing the fuel? soliciting info. for my theory!

The problem with your theory is multifaceted.
One, the stock lift pump only runs for a minute or less. Think of it as a priming pump only.
Two, after the lift pump shuts off the CAPS pump operation takes over the “pumping” duties, while the fuel supply lines operate in a negative pressure (vacuum). This is where the CAPS pump is vulnerable to many things trying to destroy it. Any leak will introduce air (cavitation). The lift pump three loose bolt issue introduces air. (ever try to drink a milkshake thru a cracked straw?)
Any slight restriction in the filters will cause fuel starvation. Adding multiple filters has the potential to multiply that restriction with just the slightest amount of particles in the filter media. This is why stock setups require fuel filter replacement at every oil change, or more often depending on the health of your fuel tank. In your situation I wouldn’t hesitate to add the FASS asap.
It’s a classic pay now or pay a whole bunch more later waiting to happen.
FWIW, I haven’t heard of one CAPS pump failure running a FASS or AirDog system upgrade. As Don says, it’s cheap insurance.

[SafariBen]

I'm ambivalent about the FASS or Airdog systems, easy to say with a P-pump. Lots of those CAPS pumps never had any problem, but enough did to make for a bad reputation. As mentioned, air is the problem, and the FASS deals with that by having a return to the tank bypassing the engine, and hopefully being mounted near the tank, it will pressurize most of the fuel system. Having the stock pump start leaking (sucking air) is bad enough, adding a filter on the suction side introduces more restriction and more potential leak spots, for worse air leaks.

[gerdutch]

Thanks Everyone for your input.

Decided to go with the FASS option after considering all the advice.

Thanks again. Great response and it helped me decide