Community Forums

bubby124 · 12-21-2020, 08:53 PM

Bought a fass fuel pump with filters I plan on installing it by fuel tank if for no other reason its easier to find a pressure leak than a vacuum leak. I also plan on eliminating the OEM lift pump. My question is the ecm is cooled by the fuel were is it at I don't want to loop around it by mistake

R.Wold · 12-21-2020, 11:38 PM

post this question here:

https://www.irv2.com/forums/f115/dea...ad-516487.html

there’s about a dozen old diesel mechanics following FFFranks’s tales of woe.....I’m sure you’ll get some good answers fast.

rikadoo · 12-21-2020, 11:56 PM

Hey Good for you, I just completed my installation about two months ago and love it. I took out the primary fuel filter and put the pump in its place. To enhance the install I put a Max tow fuel pressure gauge that connected right to the pump. Now prior to the install I had tightened the 3 bolts on the lift pump and had no leak, however after the install I ended up with a pretty good drip from the lift pump. So I had disconnected the fuel line as it enters the lift pump, then I removed the steel pipe coming out of the lift pump going to the high pressure pump. I went to a local hose builder and had him build me a 12 in hose to bypass the lift pump. Then I capped off the pump and left it in place due to it has the return lines from the injectors and pump. My biggest struggle was creating the electrical circuit to operate the pump.
Have you decided how your going to deal with the return line to the tank? I also cut the wires to the lift pump and installed a relay to trick the ECM.

Ljwt330 · 12-22-2020, 12:03 AM

Quote:

Originally Posted by bubby124

Bought a fass fuel pump with filters I plan on installing it by fuel tank if for no other reason its easier to find a pressure leak than a vacuum leak. I also plan on eliminating the OEM lift pump. My question is the ecm is cooled by the fuel were is it at I don't want to loop around it by mistake

Cummins engine, right? By eliminating the oem lift pump, I assume you mean to leave it on the engine but by-pass it with the fuel supply lines. If you simply connect the fuel supply line from the tank/FASS pump to the fuel line from the lift pump outlet, you will not be disturbing any other fuel flow to the CAPS or to cool the ecm.

The ecm is located about half way between the lift pump and CAPS pump, bolted to the block, with some large wire looms attached.

bubby124 · 12-22-2020, 11:38 AM

Yes I'm going to leave the oem pump just not run the fuel through it. Thanks for the ecm location what relay did you use to fool the ecm.

Ljwt330 · 12-22-2020, 11:41 AM

Quote:

Originally Posted by bubby124

Yes I'm going to leave the oem pump just not run the fuel through it. Thanks for the ecm location what relay did you use to fool the ecm.

Any simple relay from an auto parts store. You only need a current draw from the coil in the relay, terminal 85 and 86, to fool the ecm into thinking the lift pump is still in the circuit.

Alpine36 · 12-22-2020, 11:45 AM

One of these "Bosch" type relays or similar, hook the two ECM wires to terminals 85-86.
Polarity makes no difference, you're simply energizing the coil for the ECM to sense a load.
https://www.parts-express.com/pedocs...tion-guide.pdf

Edit...or what Larry said

bubby124 · 01-08-2021, 08:11 PM

Well have my new fass pump ready to install my Windsor has a connection on drivers side and passenger side does anyone know which side is supply side and return line

jacwjames · 01-08-2021, 09:15 PM

I have been collecting information on a Fass install, I had downloaded this from a post. I have not done the install so can't guarantee accuracy. Keep us posted!

rikadoo · 01-09-2021, 12:26 AM

Heyy bubby so ya know, fass doesnt recomend conneciting the FASS teturn to the engine return line. I took out the connector to my vent line, put the current vent line to the side of the “t” fitting then ran the fass return from the top of the “t” it works GREAT, no tank pressure an no vacum lock in the tank

veraken · 01-09-2021, 08:01 AM

I have an older MH. Has anybody installed a Fass system on a mechanical engine?

bubby124 · 01-09-2021, 09:37 AM

Yeah I'm not going to tie into the factory return line I just need to identify the supply line to hook to the new pump

rikadoo · 01-09-2021, 10:26 AM

What I know of fuel lines is the supply line is almost always bigger of the two, and because of reducing the amount of "slosh" they always place the pick up and return in the center between the tank baffles.

Trexoffroad · 01-20-2021, 07:21 AM

Quote:

Originally Posted by jacwjames

I have been collecting information on a Fass install, I had downloaded this from a post. I have not done the install so can't guarantee accuracy. Keep us posted!

If I am reading this diagram correctly, the FASS provides the pressurized fuel to the factory lift pump? Does this mean the lift pump remains “functional” and no wiring “tomfoolery” is required?

Does the lift pump create any issues for the FASS system?

And On a different note:
When installing the FASS...how much fuel is spilled? I want to install my own but need to do it at my storage area and I’m sure they wouldn’t appreciate, or tolerate, me making an obvious mess.