MSU studies E20 effects on fuel pumps, sending units

By Erin Voegele | March 05, 2009
Web exclusive posted April 7, 2009, at 4:00 p.m. CST

A study recently conducted by the Minnesota Center for Automotive Research at Minnesota State University, Mankato has found that increasing the amount of ethanol blended into gasoline from 10 percent to 20 percent causes no significant change in performance of automotive fuel systems. The study, which examined the impact E20 on the endurance, wear and performance of automotive fuel pumps and sending units, is fourth in a series of research projects conducted to determine the effect of E20 on fuel system components.

The study looked at eight models of fuel pumps and three models of sending pumps. Three identical versions of each model were run for 4,000 hours using one of three different fuels - gasoline, E10 or E20. The 24 pumps were selected to represent a variety of manufacturers, model years, common vehicles and designs. Gasoline and E10 were used in the study as reference to identify what effects two accepted fuels would have on the pumps and sending units. According to the study, fewer sending units were tested than pumps due to the similarity in the silver alloy resistive contact strips.

Only electric automotive fuel pumps and sending unites were tested. Performance data was collected before the study started and then every 500 hours until the study's conclusion, at which time the pumps were disassembled and inspected for wear.

The eight models of fuel pumps that were tested include:
  • • Volkswagen Passat 93-94

  • • Jeep Wrangler 99-00

  • • Ford truck 90-93


  • • GM TBI tuck pump 87-92

  • • GM PFI early 90's rollervane


  • • GM port pump 00-02

  • • Toyota Camry LE 02-05

  • • Honda Accord 98-02


  • The three models of sending units that were tested include:
  • • Jeep Wrangler 99-00

  • • GM port pump 00-02

  • • Honda Accord 98-02



  • The study found that the pumps showed significantly less wear when tested with E20 than with gasoline, and concluded that overall E20 did not have any greater negative effects than gasoline or E10 on the fuel pumps tested. It also showed there were no substantial differences in the performance of the sending units tested in the three different fuels. Furthermore, the study found the cleansing affect of the ethanol fuels was very apparent. The pumps and sending units immersed in gasoline were coated with residue, while the same items in E10 or E20 displayed little or no residue. While some pumps tested in E20 had light surface corrosion, they were not corroded to the extent that function would be affected.

    According Renewable Fuels Association President and Chief Executive Officer Bob Dinneen, the results add to the growing body of evidence that is proving the efficacy of higher level ethanol blends in vehicles on American roads today. "The State of Minnesota continues to lead the nation in a renewable fuels revolution, passing the first mandate for the use of 20 percent ethanol blends and continuing to provide the scientific evidence to support it," he said. "Increasing the amount of ethanol utilized in American gas tanks is essential to the goals of reduced foreign oil dependence and increased green economic activity. This report helps move the dial in that direction."

    Minnesota State University, Mankato conducted the studies as part of the process to receive a federal waiver from the U.S. EPA. The waiver is necessary for the state to proceed toward the mandated goal that ethanol comprise 20 percent of nearly all gasoline sold in Minnesota beginning in 2013. The study was based on nationally recognized standards and protocols to ensure research quality. Support was provided by the Renewable Fuels Association, Minnesota Corn Growers Association and the Minnesota Department of Agriculture.