Archived FASS help

[cwarner]

My FASS died on the way to work today. It is blowing the main fuse. Since I'm at work at the moment there isn't much I can do. I replaced the fuse and it ran for about 10 minutes and blew the fuse again. When it was running it was putting out the proper amount of pressure. The filter has been replaced within a month.

The problem is I am leaving for vacation Wed. morning for a week. The truck will be sitting for that time so I would like to have this problem fixed. I only have a short time tommorrow to diagnose this , due to a tight schedule and work.



About a month and a half ago I did the check ball upgrade, and brush cover upgrade , and replaced the one brush with the one supplied. Everything was fine after that until about two weeks ago. Then the pump would run intermittiently. I then took the brushes out and cleaned the contacts, due to some damage on the new brush ( my fault) I had to replace with the old. I also then cleaned all the electrical connections.

The pump worked flawlessly until today when the fuse popping issue started.

Anyone have any ideas as to what this could be ?

 

[SRadke]

Poor/corroded wire connection? Is the motor or wiring harness getting abnormally hot anywhere?



-Scott

 

[cwarner]

I just went thru all the connections (under the truck) about a couple of weeks ago. I need to look at the underhood connections in the morning. I will try another fuse and see if anything is getting hot.

 

[Mundgyver]

The FASS uses brushes in the motor. Those need to be inspected and replaced if badly worn. You might also need to use some low air pressure and gently blow out the brush housing to get rid of the dust build up. My bet is the brushes are worn down.

 

[cwarner]

I think what I'm going to do is make up a pigtail and plug the Fass in using a battery , if it still pops the fuse then I know it's in the pump and not the truck wiring.

 

[cwarner]

Due to trying to get ready for vacation tommorrow morning I've only been able to swap the fuse out. And again pump worked fine, for about 10 minutes. I was able to feel the pump after it blew the fuse and it did feel warm to the touch. I have a doctors appt. in a half hour and after that I will try the pigtail thing. The worst part is I have to drive this truck, so it's killing me and probably the VP seeing no fuel pressure. I've already gone thru 3 fuses this morning.

 

[cwarner]

I have a pigtail hooked up and the pump is running, pressure is fine but the pump is very hot. Almost too hot to touch. Is this normal ?

 

[SRadke]

Doesn't sound normal. The pump should be cooled but the flow of fuel shouldn't it?

 

[cwarner]

Well I think I've solved the problem, thanks to Josh at Diesel Performance Solutions and Rebecca at DPP.

After running the pump off the battery using a jumper harness for 15 minutes with no problems , it obviously points to the wiring on the truck. Everything looked good but I did notice some rust around the relay under the hood. Swapped the relay out and the pump stayed working all the way to work which is 16 miles.

Apparently the 150 pumps do run pretty hot. Which kind of surprises me , I didn't think an electric motor creates heat like that unless there is a problem.