Electrical Upgrade/Adjust Fuel Sending Unit

[TSB8C]

So I started noticing my fuel gauge acting weird. I have a Dakota Digital gauge setup, so I knew it wasn't the gauge. Attention turned to the fuel level sending unit in the tank. I put in a new Crown unit about 4 years ago when I started this build, including an electric in-tank pump for my fuel injected engine. So a bit disappointing to start having issues with the sending unit after only 4 years. Thankfully I had made a cutout panel in the floor to access the tank opening without dropping the tank. So an easy-peasy work effort at least.



Once I removed the fuel level/pump assembly from the tank, I immediately saw the issue. The cheap Crown plastic float had gas inside it. There is a small pin hole or hairline crack somewhere that is letting fuel seep in. Strange however that squeezing the float wouldn't force any gas back out so I could see the hole or crack. Nevertheless, it has to go.



So I ordered a brass float, Scott Drake Part # C0AZ-9202-B off Amazon for about $8. This is an exact size and shape replacement that clips right into the float arm loop on the Crown assembly.



And while I had it out, I double checked the resistance readings using my multimeter to ensure that the adjusting tabs on the assembly were set correctly so that full and empty (the full travel of the float arm) gave the proper readings. These stop tabs are easily bent slightly left or right with some pliers to allow or restrict how far the float arm can travel at both extremes (empty and full).



With the new float clipped in and the tabs adjusted and the readings verified, all ready to go back in.

For anyone interested, that's a Walbro GSS342-400-791 electric pump supplying the 58psi for the engine. It comes with the rubber isolator (for sound) and the intake filter on the bottom. Just remove the stock sock filter and cut the pickup tube to length, put some rubber fuel line and clamps rated for fuel injection using a length that lets the new filter sit 1/4 inch or so off the tank bottom.

 

[Patrick]

Your fuel pump is four years old. Replace it.

 

[TSB8C]

Your fuel pump is four years old. Replace it.

These pumps are rated for well over 75K miles, depending on fuel quality and whether you keep it submerged in fuel (stay above 1/4 tank or so) or whether it's allowed to run more often while not submerged. Gas acts as a coolant for the pump if it remains submerged in fuel most of the time. So running your tank low frequently can reduce the lifespan. My tank was also new 4 years ago, so no real dirt/debris to worry about either. I have about 25K miles over the past 4 years since it was installed. I certainly expect another 30K - 40K miles before any issue with the pump itself. And with the access panel in the floor, easy enough to replace when the time comes. This job of replacing the float took all of about 1 hour, including the meter readings and adjustments made.

 

[Project86]

Good call on the brass float and sending unit access. I'm gonna order a float for when that comes. I did send unit access on the first two jeeps we built. I used the Holley external pump, simply because it would be easy to change if needed. Guess what? It was needed one day on the side of the road in blistering heat. Glad I had a backup and tools needed.

 

[Armyvet25]

I hate those plastic ones, always fail, good catch
what's a good external pump to use for a carburetor, do you still need a pressure regulator?

 

[TSB8C]

I hate those plastic ones, always fail, good catch
what's a good external pump to use for a carburetor, do you still need a pressure regulator?

You looking for an electric pump for carb use, or a mechanical engine-driven pump? I prefer Holley pumps. They make a number of options for carb use in the $50 - $100 range, depending on your GPH need. Pressure wise, about 4-7 psi is needed for most carbs. No separate regulator needed. They do also have mechanical engine-driven pumps, but I think those are overrated for most people's needs. Holley's #12-427 is a great electric choice for carb use at a good price and can be used for all gas types (different grades, ethanol blends, additives, etc).

 

[Project86]

I hate those plastic ones, always fail, good catch
what's a good external pump to use for a carburetor, do you still need a pressure regulator?

If I remember correctly, I used the Holley 2225. I'll verify that before lunch tomorrow. No regulator.