Not sure if this should go in general, but it imvolves accessories mostly. When I had the FASS brush wear out, the company said that this usually comes from poor ground. Recently I replaced the brushes at home and was dissatisfied with the wear of the same brush. My unit is grounded to the frame. I now have an expensive vacuum pump on the truck that has brushs.

I am a ham operator for years so have some knowledge of filters, but thought I would run it past the board. What kind of filter would insure clean DC to the pumps. I am more associated with noise filters. How about a diode and cap across the input. What filter would you recommend and the values? I do get quite a bit of hash noise in my system. Not concerned with the noise here, just the clean DC for the units.

 

I'd go for a cap across the poles of the motor to reduce brush firing. Diode won't be necessary IMHO.
Sizing of the cap depends on motor amps, volts and frequency of the rotor field changes.
I am not an electronics guru!
HTH
AlpineRAM

 

have you checked the voltage drop @ the FASS? I have heard of voltage loss, poor circiut completion ie; bum ground, dirt,bad bushings, and over load causing brush wear, but are you sure there is not a lame brush holder or is the armature rough? I would be mad as a hornet if I had to install hash filters and caps and such, I think you are trying to build a trouble free fuel system not a nasa comunication system, haulin' thanks for having luck so bad it makes mine good

 

The ground is direct to the frame close to the pump, the hot wire is direct from the battery through a relay fired from the ASD relay. I am just looking to ease the system just in case. I was run a few months with the power coming from the stock harness and this probably started the problem.

Alpine... The design of the brushes are a complete unit, spring, wire lead, and a contactor that it clamped in place by the plastic brush screw that holds it in. I had one brush go out and stop completely so I am sure there is some damage to the armature, but a new motor is $250, don't need to go there unless I have to. I am setting up a stock lift pump with 3/8 fittings so that if I do have it go out or have to rebuild the motor, I will have a back up while it is out. I figured a cap across the leads would smooth it greatly, guess I will have to drag out the books and figure the mfd for it. Also am considering a direct ground wire to the battery, that may be better than a cap.

 

Also, the diode will have a .7 volt drop across it. So, don't do that.
Theses trucks need noise filters. build your own. Run the power thru a coil with caps to ground on each side of it, you will need to figure out what sizes work best.
Also make sure the ground at the frame is clean and tight.

 

try running a ground wire straight to the battery
Clark

 

I noticed that at idle the voltage is dropping, used to stay at max at idle. So I went back to Advanced where I purchased the alternator and they are going to swap out the alternator. Looks like I am getting AC in the system from a bad diode. When I get the chance I will also run a direct ground wire as that should help also.

 

I'm with High country, do a voltage drop check,after you install the Alternator, from the Neg. battery to engine, chassie,body and any component you are having problems with.

 

Yip a bad alt will induce noise. Like stated, check the volt drop across ground wires. Being electron flow, all the current leaves the negative side and enters the positive side.