OK, so I bought a 1987 E30 for enduro duty, and I’m still going to buy at least one more for a sprinter.
I want the 87 enduro car to be able to pick up all of the fuel, and I obtained lots of useful help here. It seemed like a lot of folks didn’t know why 55l cars starved for fuel, and the only known fix seemed to be a new tank and crossover tube. If you’re on a budget, let me help you along and tell you why things really aren’t working.
First, this car has two fuel pumps. In the tank, on the passenger side, is a low pressure feeder pump. This pumps fuel to the high pressure pump, which is on the driver side of the car, on the frame rail. The low pressure pump gets fuel from both halves of the saddle tank through a crossover tube that runs at the very bottom of the tank.
I’ve owned two 1987 cars. It seems the passenger side saddle on the tank always gets dented in, whether it be by running something over, or a 2 post lift hitting the tank. When this happens, depending on where the dent is, it can ram the fuel pump assembly with its carrier into the top of the tank and bend or break something, so pull the fuel tank and carrier and look at it all. I’m also learning that you can’t trust whoever worked on the car before you, as when I pulled the in tank low pressure lift pump today, I found a Walbro GSS 307 pump where the low pressure pump should be. This, friends, is a 255lph big daddy pump. It should never be here. On top of that, they used fuel hose to connect the outlet of the fuel pump to the nipple on the top of the fuel plate. This sounds like a good idea, but regular fuel hose is meant to carry fuel, not be submersed in it. If you need hose that can be submersed, you need submersible fuel hose, which is rare. Regular fuel hose can be used for a month or two, but eventually it delaminates in the tank, and the fuel flows out the hose casing instead of where it is supposed to go.
All of that said, here’s really why things dont work. First, lots of these tanks have crud and rust in them, and sometimes, the crossover tube is nasty. So, most people clean out the crossover tube, and things get a little bit better, but not all the way better. Here’s why. The passenger side low pressure lift pump sits down in the middle of a little bowl that tries to keep fuel on the low pressure fuel pump. This little bowl has sides that are about two inches tall. That little bowl, however, has to get fuel in it, and it only has one really small 1/4 inch hole in the front of the little bowl that allows fuel from the tank to fill the bowl. If you had crud in your crossover tube, you most certainly have crud in this little hole, and your bowl isn’t getting independent fuel flow from the tank. When the tank is full, this doesn’t matter, as the fuel level is above the sides of the bowl, so it doesn’t matter. But if this little hole is plugged when the fuel level is equal to or below the sides of the bowl, your low pressure pickup pump does not get any gas unless some sloshes into the bowl, or unless a few drops make their way through the crud into the bowl. Long story short, work a little pipe cleaner in there and clean out the hole in that bowl. If you have a clean crossover tube and a clean little hole in the bowl, things will work as intended and you will be able to pump a good bit of the fuel in the tank.
If you need to pump all of the fuel for an endurance car, stay tuned, as I’m setting up the enduro system now and will hopefully have something positive to say about it soon.
-Scott