Conversions & Hybrids - external fuel pump location problems

Right now my walbro external pump is located above the feed from the sump in the tank. At first it seemed to work fine but now the pump is making a much louder high pitch whine sometimes. I am thinking either the fuel filter is becoming clogged or the location of the pump is starving it for fuel. Also when it does make this high pitch whine the car barley runs from loosing fuel pressure. Anyone else have this issue?

do you have a prefilter? I have one on mine and it did get clogged and acted the same, and my walbro pump is about 4 feet out of the tank, so starving shouldn't be an issue.

I installed a 10 micron prefilter thats cleanable, works great.

No prefilter since I use the corvette filter/ regulator. Everything is new but maybe the filter got clogged from the gas tank sealer that might have came loose.

Its a good idea to run a prefilter, especially on a high pressure fuel pump, as most anything that goes through them will cause increased wear and reduce the pump life, unlike the old diaphram style pumps.

I run one like this, http://www.summitracing.com/parts/SUM-230102/, 40 micron, not 10 like I said before. But easily cleanable and fairly cheap.

I will go ahead and get that filter and install it before the pump to prevent this from happening again. Hopefully the pump is fine and only my filter is clogged up.

Sounds like you might be onto the problem. You definitely need a prefilter, especially right after a new build. I scored and ruined a $250 Mallory pump when junk from the new build got into mine. What really sucked is I did have a prefilter, but somehow rust particles got past it and into the pump.

From what I have read most manufactures recommend a 100 micron filter in front of a rotary vane pump and the 40 micron in front of a georotor pump. The georotors have finer tolerances so they need the finer filter. You want something with low head loss. Can't afford much pressure drop before the pump. Definitely get something that is easy to clean, then clean it often for the first couple of tanks.

I would also pull that pump off and back flush it to clean out whatever may be in there. Some have a metal screen at the inlet.

I would also be a good Idea to mount the pump as low as you can safely mount it.. The gravity and siphoning effect will help feed the fuel to the pump.

As you should know that fuel pump are designed to push fuel and sucking/pushing fuel is not one of its better features..

Thanks for all the replies guys! Should have everything fixed by the end of the week. Its sucks I have to spend so much replacing the filters. 40$ for my current filter/reg plus 30 to 40$ for a pre filter...

Thanks for all the replies guys! Should have everything fixed by the end of the week. Its sucks I have to spend so much replacing the filters. 40$ for my current filter/reg plus 30 to 40$ for a pre filter...

the prefilters are cleanable, so once you have one no need to repalce them and should really save the life of the Corvette filter.

I know your trying to save some money.

http://www.aztpi.com/product.php?productid=25&cat=8&page=1

These clear nylon filters work great as a pre-filter to the Walbro in-line fuel pumps. The element is not quite as fine as the other filters shown here but they are perfect for protecting the pump from potentially damaging debris. Another benefit is that, because the housing is clear, you can visually inspect the state of the filter. These filters should never be used on the pressure side of any fuel injection pump! They are designed for very low pressure applications. For high-pressure applications try our G6332 Filter.

Danno74Z

Although a pre-filter is a great idea, it may not be the cause of your problems. Do you know if your Walbro is a self-priming fuel pump? Weldon makes some that are self-priming, but the popular Aeromotive A1000 isn't. If you read Aeromotives installation instructions, it states that the pump has to be below the fuel supply. The reason fuel pumps that are not self-priming have to be mounted below the fuel supply is because if they're not, then every time the vehicle is turned off, the fuel in the feed line drains back downhill into the tank. When you start the car, the pump is running full speed while completely dry until it sucks fuel back up from the tank resulting in excessive wear.

I have no idea if the walbro pump is self priming or not. I need to find out...

Update and my fuel pump problems. I removed the tank and the pump. I looked in my tank and most of the tank sealer I had used had came loose in chunks and was floating in the tank. I then looked in the pump and it was full of that sealer. It was completely clogged. I cleaned out the tank and the pump and tested it out. The pump was nice and quiet and worked fine. Now after a few days it has started whining loudly again.... I did install a clear prefilter so I can easily check it out. I think my enitre fuel system is setup wrong. I have a sump in which the inlet and return and right next to each other. I think the return pushes the fuel away from the other port causing issues as well. I will post some pics later of the fuel system.