Diesel-Dan

Chris,

If you can, get a 7/16th/11mm Gear wrench and pull the T-block/Motor off the top of the FASS Base. That is a pic of the older motor...but its all the same. You can do this in the truck. Check to see the condition of the o-rings and check ball. Make sure that the ball has no debris where is needs to seat. You are getting air leaking in somewhere....

Water Sep. tight? Check thoes things.......

Stamey

I just changed the filter and sep. I made sure they were tight then, and loosened the sep today as I went through the instructions, and of course, tightened it back up.
I will try your suggestion tomorrow evening.
There are just 2 7/16" bolts hold the the T-block to the base, then the 2 bolts holding the motor bracket?
I am thinking I can just loosen the clamp that holds the motor and slide it out. Does this sound right?

Thanks,
Chris

Diesel-Dan

Depends if you have the new or old motor.

Old motor: remove the 2 bolts out of the pressure manifold. do not loosen the clamp. Then remove the 3 short bolts on the base of the t-block and on long one going through to the bracket.

New Motor: Loosen the 3 short bolts and one long one on the base of the t-block. No motor clamp.

Stamey

I have the old motor. Found it easiest to take the bracket loose from the frame, then I could see the top of the pump, and what might fall out, and the dirt that can get in, when I pulled it apart. This allowed me to clean it off before pulling it apart also.
The ball looks like a little black rubber ball, and seems concentric. The O-rings look fine.

What's next?

Thanks,
Chris

Stamey

Pics of the pump under the T block:







Thanks,
Chris

Diesel-Dan

You need the 5/8" Ball update.......that there is the 3/4" ball. They had issue of sticking under the T-block. This would cause the pump to hesitate to build pressure until the check ball is reseated. BUT would not cause the unit to loose prime per say. Its just by-passing the pump. Contact a dealer for the ball.

PN of the 5/8" Buna Ball: 1901-625-5939

Have you looked into our motor update program that is going on now?

Torque for the T-block bolts to 110 in/lbs

I really dont see anything in the T-block/Pump causing a loss of prime........Just work your way back to the tank and recheck all the connections.......Try to just hose clamp the suction line stright to the tank fitting. Take the Quck Dissconnect out. See if that helps.

Once you get fuel pressure, is the truck starting right away?

Stamey

The engine starts without fuel pressure, or that little pressure the pump puts out until the engine is running. It seems like something downstream in the fuel system will not allow the air to purge and the pump can only get the pressure up to 3-4 psi until the engine is actually running. As I said, I have 3-4 psi until the truck is running, then it jumps up to 15+ psi. The time it takes to jump up varies, depending on the level of the tank.
I am not using the quick connect to the tank. That leaked like a sieve out of the box so it was eliminated for a clamp at installation time. At this point that hose is irrelevant as I am sucking from the bucket right now.

Chris

Diesel-Dan

Did you ever by-pass your gauge isolator? Very strange issue you got going on here. Ill keep thinking on this end.......

Stamey

No, no bypass of isolator.

Thanks,
Chris

Diesel-Dan

Try that and see what your gauge does. Would like to elimate the gauge/isolator as a possable cause 100%.

Stamey

I feel like that's not it because the motor noise is also different when this is occurring. The tone goes down, and the motor suddenly sounds like it's working when the pressure comes up.
Is this your phone number on the side of the FASS? I'll give you a call.

Thanks,
Chris

Diesel-Dan

Chris,

If you call here, you will be directed to the dealer that sold you your unit. If you need to talk to me directly, i ask we keep it on the forum...Brad wanted it on a public forum so others that may have issue can be helped. If you call me on the phone, it cuts my dealers and others out of valuable information that might help someone else with a similar issue.

What is your SN#? I would recommend replacing all the o-rings and gaskets just to get the unit back up to 100% in that sense. I would also give that motor update some serious consideration. That would freshen up the upper half.

tenmile

Rather then create my own thread, i'll jump into this one.

I'm experiancing something similar- my pump used to (when new, about 9 months ago or so) push out around 19-20PSI, and only slowly lose prime (I could watch my mechanical FP gauge-no isolator, which is tapped in right at the port on the FASS slowly drop from 20 down to 0 over the course of a minute or so (seems like this was too fast apparently?)) . Recently about two months ago, the pump started wavering in it's fuel pressure- the gauge started jumping from 16-18, but wouldn't not keep it steady. At the same time, I began noticing a small leak coming from the FASS. I checked all the lines, fittings, filters, the whole bit, and it wasn't leaking from there at all. It seems that it was leaking from in between the two 'plates' that hold it together. I have not taken the whole thing apart, but are the odds that one of the O-rings is bad or something similar, and causing the whole getup to fail? And if so- are these parts covered under warranty? I'm embarking on a 15k road-trip in the truck here in a month and want to get all the issues squared away before I take off! It's a new-style pump, if that helps!

Thanks!
-Mack

Diesel-Dan

Mack,

Usually if you have such a leak that would cause a pressure drop.....you would have a puddle under your truck the size of Texas! haha....BUT with that being said......the unit might be sucking air rather than leaking fuel...which could be causing a pressure fluctuation. My suggestion is first confirm your gauge operation. Even though there is no isolator....your gauge could be telling you funny things. I was always taught when I wrenched for a living, never assume anything, always test it. Once that is confirmed good, try the 5 gallon bucket test. Make sure you have no restriction issues with the tank. As for the leak, I can get you any o-ring through a dealer if you so choose to tackle replacing them yourself. If you have a unit with no seal (wire and lead seal), its a cake walk. BUT if your leak is coming out of the weep hole, you will need to get with your selling dealer and talk with him. Give him your SN# and he will call me to discuss your options.

Clean the pump up with some brake clean to start from square 1. Then run it and get an exact place the pump is leaking from. Keep an eye on the weep hole. Let me know if that helps......

Dan

zukgod1

Sure is nice to have you here Dan.
Hope I dont ever need your help but it's nice to know your around if I do.



dan