How to: Change an NC's Fuel Pump

Pump Assembly
Pump Assembly The Pump assembly pulled apart Area behind passenger showing the uncovered fuel tank

20 June 2014 / Guy Coles

Replacing the Fuel Pump / Filter in an NC

DISCLAIMER
The MX-5 Club of NSW does not warrant that this procedure is correct and is meant as a guide only. If you have any reservations about the procedure or your ability to carry this out, consult a professional mechanic

ATTENTION :  All entries in CAPS are non negotiable  you MUST have these or do not even bother and pay someone professional to do it.

You will need:
WELL VENTED AREA
a low fuel tank fill – do not proceed with a full tank. Low to empty recommended
10mm open ended spanner for the battery
Medium Phillips screwdriver
Medium Slotted Screwdriver
QUICK RELEASE FUEL LINE TOOL  (preferably the Mazda tool)
DENSO 38mm FUEL PUMP or better. Don’t buy a cheapo Chinese knock off.
GENUINE OEM FUEL FILTER PART NUMBER LFB6-13-ZE1 – nothing else will fit ($29.65 from Mazda).
Pump Assembly

Warning – this is a procedure that will have you in touch with an open fuel tank and fuel fumes. Make sure that you are away from flames or sparks and in a well vented area. If you feel light headed or effected by fuel fumes, immediately cover the area and seek fresh air.  Have a Fire extinguisher and fire blanket nearby.

Procedure:

  1. Disconnect the battery and isolate
  2. Slide both seats forward to the full extension and tilt forward (or remove – recommended)
  3. Remove the center console
  4. Remove the front Style Bar Covers
  5. Remove the sill plates
  6. Remove the seat belt covers
  7. Remove the Plastic rear door jamb plates
  8. Remove the Plastic panel behind the seats
  9. Clean the area behind the LHS seat where the access panel to the Fuel tank is. Recommend MAF sensor cleaning spray and a clean rag. Be VERY meticulous, you don’t want rubbish falling into the tank while it is open.
  10. Remove the 3 screws on top of the Fuel pump cover and place cover carefully
  11. Using the quick release tool, remove the fuel line from the fuel pump housing. Be careful not to break either the fuel line or the plastic connection on top of the housing
  12. Remove the electrical connection
  13. Remove the 8 screws holding the housing in place and slowly raise the housing out of the tank allowing the fuel to drain back into the tank. You will have to compress to sprung top section to clear the inside of the style bar.
    Area Behind Passenger
  14. Place the housing on a clean rag and allow excess fuel to drain off
  15. Place a rag over the exposed fuel tank
  16. Remove the float, the clip is located on the side
  17. The Fuel pump is located in the cylindrical white tube inside the housing and is held on by 3 clips.  Gently undo the clips and remove
  18. At the base of the fuel filter there is a plastic cap with the filter that is held on by 5 or 6 clips. Using a flat edge screw driver, undo the clips and remove. If you are replacing the filter at the same time (recommended) it doesn’t matter if you break the clips and the new filter comes with a replacement cap.
  19. Slide the fuel pump out of the housing and remove the white plastic spacer from the top to use on the new pump
    Dis assembled Pump

 

Re assembly is the reverse of the previous procedure with attention to the following:

  1. The fuel filter requires quite some force to get all the clips in, don’t worry you won’t break it
  2. Make sure that you clean both the top of the fuel tank as well as the seal on the housing so that there are no leaks.
  3. When placing the housing back in the tank, feed the float in first and compress the housing to clear the style bar
  4. Once the housing has been screwed into the tank and before fixing the top plate, it’s a good idea to connect the battery and start the car to check that it’s all connected correctly and that there are no leaks around the quick release fitting