FASS siren
 

About three weeks ago my FASS 150 started changing pitch (whine) relative to throttle position. It is very noticeable when I am driving, not to mention annoying! I have had the pump/filter system for a little over 1 year without having this symptom. The only thing I did different at the same time I started noticing the variable whine was install Smarty. Another thing it (FASS) started doing at the same time was cycling for the full 20-30 seconds every time I cycle the key. It used to run only for a few seconds unless I bumped the key.

I set the truck back to stock software, but no change. When I put 12 volts to the FASS, it sounds like it normally did/does when the key is cycled, but now when the truck is running, the pitch of the pump increases with throttle position. IT SOUNDS LIKE THE COPS ARE AFTER ME and its driving me CRAZY!

Has anyone ever heard of such a thing? Is it possible for the pump to get more than 12 volts? That's what it sounds like is happening.

Joe

No but mine surges really bad, I was told when they do that it will not last much longer, thats been about 10 months ago, FP stays normal.

The FASS should not act any different with the engine running or not. Its more or less a separate system that all its own.

You say the sound modulates with pedal input. Is it quiet at idle? Then, say when boost builds it starts? You might check your boost clamps on your intercooler hoses and see if they are tight. I have seen this a time or to before.

NOW one other thing is when the heater grids function, the draw a lot of amps. When the grid shuts off, the pump will race due to the regulator in the alt being a tad lazy in compensating for the voltage drop. Try disabling your heater grids and see if this stops the noise you are hearing.

BUT this doesn’t explain the pitch increasing with throttle position….that is why I suggested the boost leak….

You can also get a volt meter out and monitor the pump. That might help pinpoint the cause as well.

My FASS is loud and also surges up and down. Kinda annoying sound and I even had the pump replaced one time already for the same issue. Fass stated to me that the old pupms did this and they sent me a new pump and after a few months, the sound and surge is back. Im calling them again. Let you know what happens. My psi is good, so go figure....

My FASS 150/95 has been on for over 3 years now. For the first 2 years you could not even hear it run period. I had read a lot of complaints about being loud, but mine very quiet. Then about a year ago it just started being loud, the normal pump motor whine loud, I figured it was getting ready to fail. But other than getting loud enough to hear all the time, it has never missed a beat. No surging, FP stays constant at same rate as when new.

It does almost sound like a 6.0 powerjoke turbo at idle though.

Thanks for the responses. I am thinking that it may be a boost leak now, although that does not explain why the FASS cycles for the full 30 seconds all the time now...

Im thinking the Smarty reflashed your ECM and its running the lift pump circuit a tad different. IIRC, i believe that dodge came out with an update back in 06 to run the lift pump longer due to they were having hard start issues on the ISBe engines. I bet this update is incorporated into your Smarty software.