Need Help, Fuel draining back

[Rawze]

That clears up a lot,.. thanks. This thread was beginning to be very cryptic, hard to follow.

Some things to check,...

If the level of the davco is falling off after you fill it up with fuel, it is either sucking air somewhere, or the filter is bad. I had someone not 3 days ago have the same issue with their davco unit and power loss. The fuel level would drop to BELOW the filter itself (actually, the very bottom metal edge of it). It was a cracked filter,.. and ironically, they had changed it twice.

I have also seen this happen if someone forgets to take off the black rubber gasket for the old filter, because it is very common for it to stick to the stem on the davco unit, then stack the new filter on top of it, making for 2 gaskets at the bottom of the filter. When you remove the filter,.. there should only be the bare metal stem sticking up where the filter sits, and the rubber gasket is part of the new filter at its bottom. I also recommend to others to always use a 10-micron filter instead of the Bulls$#T 50 micron one. 50-micron filters offer very little protection towards keeping ashfaultine and algea buildup out of the fuel system.

I have also seen people install the o-ring for the clear plastic bowl on the wrong side of the flange for it. Very easy to make this mistake. It will suck air and have problems, and the next person who changes it, puts it back on the same way,.. solving nothing. The o-ring goes between the clear bowl abd the top of the metal flange of the davco unit.

Here is the correct way to install it (at 2:15 in the video)...




Next,.. ensure you didn't accidentally leave the rubber gasket for the old through-flow filter (the white filter on the engine itself) stuck up into the housing where it mounts. This is a very common mistake too. I see them do this all the time at speedco. Then you put on the new filter,.. and you get double-gaskets,.. and you get engine starting problems just like you are describing. It is very possible that it can be done 2 or 3 filter changes ago, and the problem only showing up now. I have seen this more than a few times where someone has double gaskets by mistake. The only way to check this, is to remove the filter and look up into the mount to make sure it is not hidden up in there.

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If you are getting air in your suction system, (lots of bubbles coming into your davco) then it is either the davco itself, the lines (pressurizing them will find leaks),.. or in the pickup tube(s) in the tank itself.

As well,.. you may be facing multiple problems. It could very well be that you are chasing some air bubbles, but you may have bigger issues like a failing shutoff solenoid, a stuck pressure relief valve, or a bad fuel/gear pump. The IFSM is designed so that if a bit of air gets into the fuel, it will be bled off through several small leak passages throughout the IFSM before it reaches the injectors unless it is excessive.