Put a fass platinum on this last weekend everything was good and. Had 16 lbs fuel pressure. Now after a couple days, its being inconsistant jumping up and down from 10 to 17 and all over in between at an idle. No leaks anywhere. Am i sucking air?? I put my mechanical gauge on to double check and its bouncing too. Any help much appreciated. Thanks in advance

 

is your pump noise changing with the pressure reading? If youre sure you are not sucking air you could have a prob with the check ball in the pump. Take your pump return line connection line off at pump and remove the fitting in the pump and pull out the spring and check ball, if you have the black rubber type ball check it for indentions, usually the spring side will be indeted but you dont want an indention on the part where it seals against the pump. Either replace the ball with the white plastic ones or get a new black one.

 

Ill check that cause i did have to tke it off when first got it so thats a good start. It does have different pitches in the sound of it too. Sorry about the heading just noticed it. Guess my phone couldnt keep up with my typing this morning

 

Usually if the pitch is changing with pressure fluctuations the ball is junk, Ive had to replace a few after a new install. The ball gets messed up from being seated in the pump for so long while its sittin on a shelf somewhere. I think they should let whoever installs the pump put the ball and spring in.

 

do you possibly know what size they are and the best place to get one in town or if i have to order it thats fine too

 

You should be able to get them from a local fass dealer or through fass.

 

You could contact our technical support department and we can help you make sure that the ball is the issue. If it is, we can get one shipped out for you as well. The number is (866) 769-3747. Have you tried to perform a "bucket test" to eliminate the problem of a restriction in the fuel tank? Here is a link on how to do that as well and hopefully it helps you out.

 

It sounds like your cavitating the pump...

 

what should the fuel presure read with this pump? I changed the stock filter earlier this week cause i plumbed it thru the stock one also, and that got the gauge to read a steady 15 at idle. But the pump still doesnt have a steady tone to it. It doesnt sound anything close to that video, just not a steady, a slight higher pitch for a sec and back down for a bit. but the pressure doesnt change. it stays constant. ??

 

That sounds more like your sucking air, does it maintain a steady noise if you back off the water seperator? while its running also loosen the fuel filter some and see if the fuel is foamy. Sometimes you can tighten and loosen the fuel filter a few times and itll clear up, make sure you put a pan down and dont loosen it a whole bunch, just till fuel sprays out and then retighten.