Lift Pump and Sump Install Issues

[Jake707]

Ok I installed my new FASS 150 lift pump in the LLY and put in a sinister diesel sump kit at the same time. I followed the directions on both as well as a couple videos I watched. Everything went together nice and I let it sit over night with a full tank to ensure no leaks.

Started it up and it all sounded good, slight hum like a normal fuel pump up close but nothing I would cal loud. Drove it about 50 miles that day then it sat for two days. Went to start it up and it’s making a nasty grinding type sound which, from what I can read is a cavitation type sound. If I loosen the water filter screw while running the sound goes away then after awhile it will come back. All the lines are tight, I primed the fuel filter by loosening it, running it till gas came out then tightening up the filter, I even cracked the bleeder valve and completely covered myself and engine bay with gas haha. Still making this noise.

 

[Jake707]

Here’s two videos I made

https://youtu.be/zHXbtkuVTlE


https://youtu.be/TLC6Y7dbkMI

 

[Jake707]

Here’s a few pics of the install I took from when I thought everything was all good haha. I even cut down some cheap mud flaps to fit in the rear wheel wells to protect it since I used the bed bolt close to the wheel so I could tuck it higher up.

 

[Jake707]

More pics

 

[2004LB7]

Looks like a nice installation.

The sound to me sounds like its running dry or it got some junk in it. Reminds me of a bushing bearing that is worn out, makes a similar sound

 

[Bdsankey]

Are any of your lines kinked?

 

[Jake707]

Nope. No kinks in the line. All connections are tight so it should be sealed up

 

[TheBac]

Moved to Fuel Pump section. Nice job on the install.

 

[rmallen30]

Have you hooked a gauge up to it to see what the actual pressure is that it’s putting out .

 

[Jake707]

On the CTS2 it shows at idle right around 5k. While going down the road it’s high teens and in the 20s for sure. Not sure exact other than idle right now. But I know idle is 4.8 to 5 pretty steady. I believe that’s in the normal range right?

 

[rmallen30]

I mean the lift pump pressure. Not the rail pressure.

 

[Jake707]

Oh no I don’t have a gauge on that. Not even sure where I would put one?

 

[rmallen30]

You can buy a fitting that screws into the bleed screw on the factory filter housing , or put one in line , I can’t remember on the Fass but I know on my air dog there’s a built in port.

 

[LBZ]

Also the test port under the hood by the alternator works if you have the fitting for that.

 

[Jake707]

Ok I tried to test the pressure at the shrader valve by the alternator but none of the fittings in the fuel pressure tester kit at the local autozone fit. It’s def different than what I’m used to so not sure if diesels use a special gauge and fitting?

 

[Jake707]

Another thing I noticed is that plunger to prime the fuel above the stock filter housing was able to press down a few pumps. My understanding is this should be and should stay rock hard once primed right? I shouldn’t be able to press it down at all? It’s hard to tell the amount of pressure people use in the videos I’ve watched for priming fuel lines

 

[2004LB7]

If your lift pump is working properly the priming bulb sould be rock hard or at least difficult to press down. With the engine running it may be easier. If the pump is not working then you should be able to prime it up and then it will start to get very hard to press to the point it can feel solid. When the engine is running it will get soft again

 

[Jake707]

Ok got a cheap fuel pressure gauge for now to test the lift pump. It’s at or over 10 psi. Here are some videos of the gauge and the sound both running and just key on. I pulled the inlet hose from filter head in the engine bay and had suction on my finger when I pumped the primer. So just in case I replaced the inlet hose since I had extra hose.

https://youtu.be/bBuyhAlKeE8

https://youtu.be/Uq0eydZz_3g

https://youtu.be/EOIyLL9_WgA

 

[KyleC4]

To me it sounds like as if there is a restriction or it’s pulling in aerated fuel.....? When I first installed my FASS I had a surge issue and pump would make some weird noises. Pressure was erratic and would get to 12psi at times. I removed the fuel return fitting to inspect the spring and check ball. Didn’t notice anything and when I reinstalled it, all was better for whatever reason. Pressure gauge then showed only 9psi. I had it on a beans sump single port first, now it’s on a dual port. Mine is only a 95 though.

 

[Jake707]

I ran the “bucket test” after talking to the folks at FASS and the sound went away. The surging didn’t but the sound did. So that led me to believe something was would be wrong with the supply side. I noticed when I took the hose off the sump and slide a cap on to plug the tank, fuel did come out but not what I would think to rush out would look like. So when putting it back I shoved an end of an old wire hanger in there and poof all of a sudden gas came shooting out all F’in over me haha. I think what happened is some of the RTV I put around the sump to ensure a seal got in there a clogged up the port a some and was causing the suction side of the pump to work too hard. Inlet about 3-4 gallons pour into a bucket to get whatever broke free out of the tank. The sound seems more on point now and FASS will be calling me back tomorrow about a fix for the surging. So might be going the right direction now.