Community Forums

Raybo · 06-01-2017, 09:42 PM

Just finished installing new fass fuel pump with two filter system. I disconnected the wires going to the old lift pump. The fass system needs a switchable 12 volt to it. I wired it all up that way, but now the check engine lite and busser comes on. I believe it is from the disconnected fuel lift pump wire. Does anyone know to fix this

funjnt · 06-02-2017, 04:00 AM

I think I have read somewhere, probably in the repeating caps failure thread, you have to install a resistor in line with the original lift pump positive feed. This tricks the ecm into thinking the juice is flowing into the lift pump. Tell me about your install I am interested in doing it to our coach. Did you by pass the lift pump on the supply side? How did you route your lines? Thanks!

jleamo1 · 06-02-2017, 07:05 AM

Raybo, go to an autoparts store and pick up a fog lamp or a 12v relay. Connect the wires from the old pump to the coil circuit on the relay, this will energize the relay (and do absolutely nothing as nothing is being turned on by the relay) The ECM needs to see the resistance of the coil in the relay and clear the fault code.
I bought a fuel pump extension harness and put the relay in the electrical bay, here's a picture.

Raybo · 06-02-2017, 07:43 AM

Ok thank you

jleamo1 · 06-02-2017, 12:07 PM

something like this relay, connect to pins 85 and 86. You might have to clear the codes in the ECM but that will fix you up.

TE Connectivity - 1432785-1 - AgSnO Form C 12 V PI MINI-ISO Relay - Allied Electronics

Raybo · 06-02-2017, 08:23 PM

Funjnt
I reused the supply pipe from the tank. I look all over for small strainer that people talk about being above the axle but could not find any on built 2003 spartan. The supply pipe to the lift pump is the one farthest from the engine. My unit only had one fuel filter between the lift pump an high pressure pump. I removed it installed titanium 95 gph. There is a pipe chase on curb side starting above the axle but I could not get a fish tape through I was working by my self only. I ran the return pipe from filter base under the storage area and attached it to a channel running front to back along with wire for pressure gauge. Fass wants the return line run into tank fill hose with a supplied fitting but it's for a 1 1/4" hose. My fill pipe is 2" I D so I made one from 2" OD COPPER TO FIT THE 1/2 ID return pipe. I left the return pipe from the disconnect lift pump in place. If you have further questions let me know. Raybo

funjnt · 06-03-2017, 05:48 AM

Yes I have another question. Do you need to bypass the stock lift pump? If the mechanical pump pulls fuel through the factory lift pump why can't you push fuel through it? I am asking this as it would very easy to just put a pump in between the fuel filters in the filter bay without having to run and splice lines etc. Also, where did you get the switched lead?

TR4 · 06-03-2017, 08:57 AM

funjnt,

Yes, bypass the lift pump.
Disconect fuel line from primary filter to lift pump and cap it.
Install new fuel line from primary filter (outlet side) to Fass pump inlet.

Disconect fuel line from secondary filter to lift pump and cap it.
Install new fuel line from secondary filter (inlet side) to Fass pump outlet.

This is for the Fass pump without filters.

Bill

Raybo · 06-03-2017, 08:02 PM

I have my old lift pump it looks like there is restriction in it that's wye I did it though I guess you could leave it. I soldered a wire to the red wire going to the heater in the air drier. The ignition switch pulls in a relay that sends 30 amps to that heater the pump uses 4.5 amps it should handle it. If the return pipe starts to sag after use I will strap a length oh 3/4 " PVCpipe and run the rubber return pipe through it

funjnt · 06-04-2017, 06:21 AM

Well that certainly sounds quite easy. Where did you tie in the electric?

funjnt · 06-04-2017, 06:22 AM

Got it didn't see reply. Could also put in a relay off of the heater wire and use separate supply to pump that way. Thanks..

79cvx20 · 07-11-2017, 12:40 PM

Does anyone have directions and fuel hose routing diagram for installing a Fass fuel pump that comes with the two filters?

79cvx20 · 07-11-2017, 12:47 PM

Does anyone have directions and fuel hose routing diagram for installing a Fass fuel pump that comes with the two filters? It also seems like the fuel pump would work best at the fuel tank and I have a whole lot more room there anyway. The main problem I have is that I have 3 fuel lines coming from the engine. Two of them go to the bottom of the tank and one of them goes to the top of the tank . A little hard to tell which one goes where because the two that are from the bottom of the tank and the one that goes to the top of the tank go up into the tunnel . One of the ones that go to the bottom of the tank is slightly smaller than the other . I'm also thinking about installing a sump pick up . The 4th hose is for the generator.

jlckmj · 07-13-2017, 12:38 PM

OK,
I am about to start getting the pieces together to install the FASS pump, before I end up having to replace the CAPS system, but I have a few questions.

I am thinking about installing a Davco filter at the tank and then mounting the Fass pump. If I do this, do I need the titanium series with the filters, or just the pump?

OR

Do I just mount the titanium 90GPH pump with filters at the tank, eliminate the primary filter in the rear compartment, and the filter on the motor? or just the primary filter and leave the secondary filter that is mounted on the motor?
(it looks like the titanium filters clean to 2 or 3 microns, just like the secondary Cummins filter does?)

Or do I need to leave the second OEM filter on the motor?

I see that the Titanium series pumps have a return on the housing, do I plug that and keep the original return system in tact from the original pump manifold?

90 GPH and 17 PSI is really not high pressure can I get by with steel, aluminum, or copper line for the main sections and use the appropriate (flared) end fittings and hose clamps? or do I need to have fuel lines made up with crimped ends to eliminate leaks?

I will probably run new lines because mine are 17 years old, do you recommend running feed and return?

What diameter line do I need? 3/8, 1/2, or 5/8 inch? Do I need the same size for both feed and return?

I am sure that there will be more questions as I get further into this, so thanks ahead of time

Jim