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Archived Fass System Failure!

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I have a FASS 150/150 - 1008 pump that is 2 years and 4 months old. I changed the filters about 5 months ago. I have an Auto Meter fuel pressure gauge (Full Sweep Electric # 6161) that is just before the injection pump.



Today on the way to work my gauge was reading 0 psi. It has always ran at 12-15psi.



Truck ran fine but i was very easy on it. I did not want to damage the injection pump.



So i shut the truck off turned the key back on and did not hear the pump, so i bumped the starter (not starting the truck) and did not hear the pump.



I checked the fuse and it was blown (15amp fuse). So i put in a new 15 amp fuse and bumped the starter, the pump ran for about 5-10 seconds then popped the fuse.



I went and checked all the wires and relay, they checked out good. I then used an amp meter inline and ran the pump it was pulling 24 amps. When it was running it put put 11-16 psi and was jumping a lot (truck was off).



I did the test on the FASS web site where it said to loosen up 3 of the 4 bolts and run the pump to remove any trash that could have gotten in the pump. Still the same thing.



With no other option I use a 25 amp fuse and drove the truck home (only a few miles). Soon as I got home I checked the pump motor and it was not to hot, I could hold my hand on it.



Im going to go and do the bucket test to make sure theres no restriction and see if it falls back under 15 amps.



I dont want to drive it until i get this fixed and its my only thing to drive.



What can i do to get this thing going? :confused:



Sorry for the long post, any ideas would be a help! Thanks!
 
I just ran the bucket test and still the same thing. The pump also sounds really slow compared to what it use to sound like. With fuel in the bucket it was pulling 24 amps and when it ran out it was pulling 22 amps.



Maybe this info can help some.
 
Can you get the truck to a heated building or garage? I am thinking you may have a piece of ice stuck in the system somewhere. Not very likely but worth eliminating the possibility.
 
I thought about that but my truck is garage keep and heated to at around 65.



I just called the number on the side of the pump and spoke to dan. Them and Advance Diesel Service (whitch is the FASS dealer in anchorage) are going to set me up with a new top section of the pump.



Thanks for the help and ill let you know how it turns out.
 
With no other option I use a 25 amp fuse and drove the truck home (only a few miles). Soon as I got home I checked the pump motor and it was not to hot, I could hold my hand on it.



TTerry,



This won't help you with the pump, but it might give you some insight into the fuse issue.



The 15 amp fuse is not there to protect the pump itself. It's there to prevent the (probably 14 gauge) wiring from being overloaded. Wires of different sizes are rated for different currents (amperages). You already knew that. A 15 amp fuse is installed in 14 gauge circuits to prevent that wire from carrying 20 amps (or more). If a circuit is designed to pull 20 amps it will use at least 12 gauge wire and have a 20 amp fuse.



When you checked the pump itself and thought that everything was okay because the pump wasn't hot you only evaluated half of the problem. Was the wire hot? If it was a 14 gauge wire and if it carried 24 amps for a while, chances are it was hot. You risked melting the insulation on that wire and shorting it to ground. That can create a spark with the resulting problems.



At least you didn't bypass the fuse entirely. If the wire shorted to ground with NO fuse, it would have continued to heat up until some part of the conductor melted. At least with a fuse, even a 25 amp one, it would blow the fuse with a direct short to ground.



The point of all the above:

Before you replace a fuse with one of a higher amperage, be sure your WIRE can carry it.



I'm glad you are getting it taken care of and that the FASS people are backing up their equipment. Best of luck with the replacement.



Loren
 
Loren thanks for the information thats good stuff that people should know before they mess with electronics.



I was worried about over loading the wiring for the fass system so I had stopped on the way home and checked the motor and a few places on the wires and the relay to see if they were hot. I also carry a fire extinguisher in the truck too.



I got a chance to pull down the pump last night and found out that a few of the windings in the motor had burned up. The brushes look like they had a lot of life left in them and the copper on the wires comming in to the pump looked good so i dot think i overloaded the wires. Im not sure yet what caused the windings to burn up. The bearings turn nice and free, the pump rotor and housing was smooth no burs or any thing to get hung up on. Maybe it was just a faulty winding.
 
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