My fuel pressure is at 0, thought the gauge was fried, but the truck runs great.

Complete new gauge/sender and still 0

Then I remembered how the fass would whine a couple seconds, waiting for the heating elements, before start up, plus usually you can hear while the truck is running, but nothing now!

Whats going on, the high pressure pump cant be pulling fuel through the fass can it?

 

I do believe that the FASS is setup to allow the CP3 to pull fuel through it if it is not pumping. I am no expert on anything, but you should be able to disconnect line from FASS to filter or cp3 and turn key to on and see if your pumping fuel. Maybe the FASS man will chime in soon and really help.

 

[QUOTE]but you should be able to disconnect line from FASS to filter or cp3 and turn key to on and see if your pumping fuel. [QUOTE]

Just let the fuel hit the ground, right, Ill try it right now.

 

The fass has a internal bypass . If you don't hear it running I guess it isn't right? Where is the fass feeding, the cp3 direct or the stock fuel canister? Do you have the full fass with filters or just the pump. Where are you tapped into for your fuel pressure? Try doing the bucket test, disconnect the out feed from the fass and put the line in a five gallon pail. More information is available in detail in the fass manual or on their web site. My thought is don't run your rig without a transfer pump to the cp3. The dodge unlike the chevy has smaller diameter fuel feed lines that cause the restriction. Yes the cp3 will pull diesel from the tank......AMAZING!

 

Just as I figured, there was nothing,

I didnt think the cp3 could pull the fuel at all. When my stock LP died, so did the truck.

Diesel Dan is the guy to talk to right?

 

Diesel Dan is the FASS guy.

 

N.Johnson- The fass has the filters, directly to the cp3, there is a T in the line 6" away from the cp3,

I must have put on 3000 miles without the fass, truck ran like a champ, just thought the fuel pressure sending unit crapped the bed,

I cant believe I didn't even think about the noise it usually makes, when running. Hope I didnt wreck anything, does it still filter the fuel when not pumping?

 

The CP3 is supposed to be able to pull fuel through the FASS even if it's not working. Make sure your wire running to the battery has not come loose and of course check the factory wiring plug...

 

Yes the FASS has a by-pass built into it. The CP3 is not as sensitive as the VP-44....if you didn’t try to brake any 1/4 mile records...you are ok.

NOW for the FASS issue. What you need to do is check all your wiring. Batt Connections, Plug ends, and Fuse. Check with a test light at the pump. Remember that you need to bump the engine to get power back to the FASS...and that only lasts for 20 seconds or so. Having some help would be best. What is your Serial Number? This will let me know how old the unit is.


New Motor (SN: 4930 and higher):

If you have power up to the motor, try to wiggle the wires going into the unit. If power comes on intermittently to the frequency of your...well.... wiggling, the solder connection at the brush plate might have broken. We have seen this in a very small number of motors. Other than that, these motors don’t quit. That we have seen yet at least.....

Older Motor (SN: 4929 and lower):

BRUSHES. Try to tap on the side of the motor housing with power applied to the unit. If the unit starts, you have a brush contact issue. What you will need to do is remove the brushes and inspect the condition. Make sure the spring and wire are not burned up. IF all looks good, get some 3M Scotch Brite maroon pad and clean the top metal tab of the brush. Make that thing shine. (This is where most stop and the issue will continue on....but from my testing here, i have found this to be a good fix) Then cut a 5" x 1/4" strip and install in the chuck of a cordless drill so that about 4" of the strip is sticking out. Spin the drill at low speed and feed the strip down into the brush orifice of the motor. Once in, spin the drill for about 10 seconds in both directions. This is honing out the brush guides and making a good connection to the Brush tab you already cleaned. Once you get both sides done. Get some silicone and apply to the threads of the brush caps. Reinstall the brushes and caps. DO NOT OVER TORQUE! They are easy to brake/strip. The motor should run fine after this.





Something else that might be the issue, is a piece of debris might have lodged its self in the Gerotor. This is an easy fix. Loosen the 4 horizontal bolts holding the motor to the T-block. Try to run the unit. If it runs, tighten up the bolts as its running. This will allow some movement of the gear to pass the debris into the fuel filter. If it still won’t run. You can remove the motor and pump section to inspect the gear and clean. There may be a small ball and spring that is between the ware plate and T-block. It’s not hard to get back in, just be aware of it. Place some card board under you if not on concrete. Do this after you check for power to the motor.

Let me know if this helps and what else I can do for you.

 

Dan, the serial # is a 5891

I got a code also, p0628, low voltage lift pump etc.

and no power coming off the original lp harness, coming off the engine, hooking up the the fass connector, any idea why?

 

HUM.....check your onboard fuses. Look at your fuel pump relay....(DO 04.5's have them...i know 05's do.......). Definatly somethings not right if you are not getting power from the stock harness. ECM not giving a signal for some reason. You have a tuner on the truck? Something that can flash the ECM? Might try to put it back to stock. Make sure you bump the key and such....or run the engine when you check it (Just dont get wrapped up in the belts!).

We can get power to the FASS temporarily by moving the trigger wire on the FASS relay to a fuse. Hot in Run and Crank. Its the red wire between the FASS relay and stock harness.

 

I got it figured, we swapped the relay with the one off my BD brake, and tapped the pump a couple times with a heavy chisel and it fired right up. (Used an ohm meter deal, and checked the stock lift pump hook up, it was fine)

I thought only the older models had the brush contact issue? Should I clean it out like the older models anyway?

 

You cant clean the motor like the older ones. Are you sure that the relay want sticking....did the tapping cause the motor to start running?

Devon, Contact NAPT and have them call me for some options on this.