Author Topic: Fuel tank problems!!!  (Read 86 times)

Offline silverchev08@gmail.com

  • Newbie
  • Posts: 23
  • Newbie
Fuel tank problems!!!
« on: April 14, 2019, 08:43:33 PM »
85 K20....
Need help troubleshooting the following:
1. After I fill up the truck will die as I pull out once the fuel runs down the truck runs great. sometimes after the truck sits it loses prime as well.
2. As the fuel sloshed around in the tank my needle on my gauge bounces back-and-forth while driving.
3. what is the recommended fuel sending unit ? I am replacing the metal tank with a poly tank and want to get a good fuel sending unit.
4. Truck is a dual tank assembly. Deleted driver side tank and am just going to upgrade the passenger with a 20 gallon. Removing fuel valve and just running straight lines . Any best practices or thoughts on this?

Thanks

Offline 75gmck25

  • Frequent Member
  • **
  • Posts: 326
  • 1975 GMC K25 Camper Special, 350/TH350/NP203
Re: Fuel tank problems!!!
« Reply #1 on: April 17, 2019, 05:42:21 AM »
I looked up the sending unit choices online (just match the number of ports and the side it is on), and then searched locally for the same item.  I don't think there is any big difference between brands.  I recently replaced both sending units in my truck when I cleaned the gas tanks, and I don't have any problem with slosh causing a change in reading.

I recommend also switching to rubber fuel hose that meets SAE J30R9 (high pressure) or SAE J30R7 (low pressure) standards.   This is sold as fuel injection hose, but the key feature is that it holds up much better to the ethanol used in modern gasoline.  I also used fuel injection clamps, which have full circle clamping without cutting into the hose.

My first guess for you would be a bad fuel pump or a clogged filter that is affecting flow. You might also have a float level set too low, but that is usually more evident during higher throttle.

Bruce

Offline silverchev08@gmail.com

  • Newbie
  • Posts: 23
  • Newbie
Re: Fuel tank problems!!!
« Reply #2 on: April 17, 2019, 06:42:01 AM »
Thanks Bruce. Any thoughts, best practices or recommendations on a poly tank versus steel? Gonna pull the feel system apart this weekend and put in a new fuel pump and lines and delete the dual tank valve. But I'm also contemplating removing the metal tank and putting in a poly tank . Other than not having to worry about it rusting out are there any other benefits of the poly tank versus the steel tank.