HFS-4 pump vibrating
 

I’ve got an HFS-4 kit with the Howerton twin tank. My car has been down for the better part of a year for engine rebuilds and many other changes.

I actually had it on the road for about a month; I was getting ready to tune so I was testing the Aquamist kit and ran into an issue with a diode on the controller board that Richard (Aquamist) helped me sort out... thanks again for that!

Right now, the only outstanding thing is that the pump is vibrating and is quite loud. I connected a 6” hose to the outlet of the pump and cycle it for a while, here are a few videos to show the symptom.

https://www.youtube.com/playlist?lis...zFzJ1mAn14606d

Video 1: Controller jumped to SYS.
Video 2: Controller jumped to SYS, after cycling for about 4 minutes.
Video 3: Controller jumped to SYS & FAV.

In all the pump was cycled for about 5-6 minutes and the vibrating persisted. The last time the car was running with the injection tuned in, it would only make a hissing sound when spraying... so the vibration is concerning me. Getting the car ready to fire again this week, I would appreciate any assistance.

It was suggested from my local distributor/vendor, Howerton Engineering, to "remove the pump from the unit and turn while running, outlet up, to get all the air out"; is this OK to do?

Re: HFS-4 pump vibrating
 

The most likely cause is air in the pump head.

Try this:

Use a short length of 6mm hose, connect it between the pump and tank. Let it cycle for a minute at a time. Make sure the return end of the hose does not spray directly at the outlet. It will create even more trap air into the pump.

Re: HFS-4 pump vibrating
 

Thanks Richard.

To clarify; I'm to attach a 6mm hose from outlet of the pump to the filler hole on the tank?

If so, that's what was happening in the video - the line coming from the outlet of the pump was going back into the top of the tank, which was baffled and had about 3/4 gal of water in it. We cycled it for a couple minutes, turned it off via the gauge, then cycled it again for a few more minutes.

Is it OK to do as suggested by Howerton? "...remove the pump from the unit (tank assembly) and turn while running, outlet up, to get all the air out."

Re: HFS-4 pump vibrating
 

That will be my next suggestion.